2026 Southeastern Residency Conference

Authors: Cameron Howell, PharmD; Layla Marefat, PharmD 

Background: Asymptomatic bacteriuria (ASB) is the presence of bacteria [>100,000 colony forming units per milliliter (CFUs/mL)] in the urine without associated genitourinary symptoms.  Up to 60% of patients with ASB [and an additional 40% with asymptomatic pyuria and/or nitrituria (ASPN)] receive antibiotics when not indicated. Reflex urine culture algorithms are a tool used to decrease urine culture rates, which reduces unnecessary antibiotic use. Typically, the reflex criteria for these algorithms include urinalysis components, of which pyuria is the most reliable for predicting a clinically significant urinary tract infection (UTI). In 2018, reflex urine cultures were implemented at the Baptist Health System using a traditional cutoff of >5 white blood cells per high power field (WBC/HPF) for pyuria. A recent study found that <10 WBC/HPF has a similarly high negative predictive value for UTI than less stringent cutoffs. Thus, in July 2025, the definition for pyuria was refined to >10 WBC/HPF, leading to a threefold increase in overrides of the algorithm.  The aim of this study is to evaluate the impact of delivering education to providers on adherence to a urine culture guidance algorithm.
 
Methods: A retrospective chart review was conducted on adult patients at a community hospital who had a urine culture obtained from an override of established reflex criteria. The primary outcome was the percentage of inappropriate urine culture overrides. It was assessed for a pre-intervention phase from January 1, 2025, to April 30, 2025, and compared to the post-intervention phase from October 1, 2025, to January 31, 2026. Education was provided to hospitalists, emergency medicine providers, and intensivists.  Secondary outcomes included hospital length of stay (LOS), days of therapy (DOT) for patients with an inappropriate urine culture override that received antibiotics for UTI, and concordance of provider inputs for symptoms or "At Risk Population” on the urine culture order with patient chart documentation.

Results: 76 patients were evaluated in the pre-intervention group while 175 patients were evaluated in the post-intervention group. Most urine cultures obtained from overrides resulted in no growth or normal urogenital flora (76.3% vs. 62.3%, p = 0.030). Despite a reduction in inappropriate urine culture overrides compared to the pre-intervention phase, this difference was not statistically significant (57.8% vs. 48.0%, p = 0.15). Hospital LOS, DOT for those with inappropriate urine culture overrides, and concordance of provider inputs for symptoms on the order with patient chart documentation also were not significantly affected. The concordance of provider inputs for “At Risk Population” on the order with patient chart documentation was significantly higher in the post-intervention group (14.3% vs. 68.8%, p < 0.001).

Conclusions: Pharmacist education to providers was not effective in reducing inappropriate urine culture overrides. However, significant limitations were present, especially the difference in reflex criteria between groups. Nevertheless, most urine cultures did not yield clinically significant growth. Additional interventions must be pursued in addition to education to target higher adherence to a reflex urine culture algorithm.

Evaluating Antibiotic Overuse at Hospital Discharge for Uncomplicated Community Acquired Pneumonia and Urinary Tract Infections: A Retrospective Review
 
Blake McClellan, Sarah Grace Gunter, Noah Sanford, Braxton Clines, Elizabeth Covington

Abstract
Purpose: Inappropriate antibiotic prescribing at the time of hospital discharge represents a significant challenge to antimicrobial stewardship. Antibiotic overprescribing can carry serious consequences, such as antimicrobial resistance, adverse drug events, and increased healthcare costs. Studies have found high percentages of patients discharged with antibiotic durations exceeding guideline duration for urinary tract infections and community acquired pneumonia. This project evaluated discharge antibiotic prescribing at a community hospital located in the southeastern United States.

Methods: This retrospective chart review was approved by the Institutional Review Boards at East Alabama Medical Center (EAMC) and Auburn University. Study participants were screened from a pre-existing dataset of patients with infectious disease tests resulting post-discharge from August 2022 through October 2024. Inclusion criteria were as follows: findings consistent with uncomplicated urinary tract infection or community acquired pneumonia, discharged alive, and inpatient encounter with microbiology testing performed at EAMC. Exclusion criteria included patients with blood or urine culture contamination, Candida sp. growth in sputum, Pseudomonas sp. growth in stool, vaginal Group B Streptococcal swabs, no inpatient encounter, transfer to another facility at discharge, death prior to culture result, or classification as vulnerable population (<18 years or incarceration). The primary endpoint was percentage of patients with antibiotic overuse post-discharge based on the Vaughn et al. definition: unnecessary antibiotic use, excess duration of antibiotic use, and/or suboptimal use of fluoroquinolone therapy. Secondary endpoints included individual components of the antibiotic overuse definition, median days of antibiotic overuse after discharge, total antibiotic duration, duration of inpatient versus outpatient antibiotics, percentage of antibiotic course accounted for by outpatient antibiotics, percentage of patients with antibiotic order changes during hospital stay, percent overuse based on discharging services and presence of infectious diseases consult. Data were analyzed using descriptive statistics for the overall cohort, with additional comparative analyses performed between patients with and without antibiotic overuse using SPSS (IBM Corp., 2024).

Results: Nearly half (47/100, 47%) of patients experienced antibiotic overuse at hospital discharge. Overuse was driven primarily by excess duration of therapy, while unnecessary antibiotic initiation and suboptimal use of fluoroquinolones was less common. Among patients with overuse, the median number of excess antibiotic days was 3 days (IQR 2,5). The median total duration of therapy was 8 days (IQR 7,10), compared with a median ideal duration of 5 days (IQR 3,7). Most antibiotic exposure occurred in the outpatient setting (78%). When comparing patients with and without antibiotic overuse, there was no difference in overuse based on diagnosis, demographics, insurance status, or discharging service. More patients who experienced antibiotic overuse received a dose in the emergency department (17% vs. 3%, P = 0.044).

Conclusions: Antibiotic overuse at discharge for uncomplicated infections is common at this institution and is primarily driven by excess duration of therapy. The findings from this study help support prior literature and highlight opportunities for antimicrobial stewardship at transitions of care. Direction of future studies may include pharmacist-led interventions at the time of discharge to influence durations of therapy, and further evaluation of predictors of antibiotic overuse at discharge.

Clinical Management and Outcomes in Patients with Coagulase-negative Staphylococcus spp. in Lone Blood Culture Sets
Benjamin K Battle, Andrew B. Watkins
FMOL Health | St. Dominic
Background/Purpose:
Blood cultures remain the standard for diagnosis of bloodstream infections, but blood culture contamination may lead to inappropriate antimicrobial use and increased risk to patients. Contaminants are often skin flora organisms, and coagulase-negative staphylococci (CoNS) are the most commonly identified microorganisms found in contaminated blood cultures. Differentiating contaminants from true pathogens proves a challenge as these microorganisms could potentially cause true infection. This diagnostic uncertainty and desire to treat may lead to unnecessary or inappropriate antibiotic use and/or Infectious Diseases (ID) consults, which result in clinical and economic burdens for the patient and hospital. St. Dominic Hospital has placed an emphasis on reducing blood culture contamination based on an increase in contamination rates over the last year. This study seeks to characterize the clinical management and outcomes of patients with CoNS growing in lone blood culture sets at St. Dominic Hospital, as well as to analyze overall contamination trends and financial impacts of these potential contamination events.
Methodology:
This single-center retrospective observational cohort study includes patients admitted to St. Dominic Hospital from January 1, 2025, to August 31, 2025, that are of at least eighteen years of age with CoNS on one set of blood cultures. Patients with blood cultures positive for Staphylococcus lugdunensis or prior blood cultures with CoNS in multiple sets during admission are excluded. The primary objective is to evaluate the use of antibiotics in patients with CoNS in lone blood culture sets. The secondary outcomes include reviewing the overall trend in hospital blood culture contamination rates, frequency of infectious diseases consults, costs attributable to potential contamination events, impact of contamination on pharmacist workload, and outcomes between patients receiving antibiotics for greater than three days compared to those receiving antibiotics for less than three days.
Results:
A total of 100 patients were included for analysis, with 56 (56%) receiving antibiotics for coagulase-negative Staphylococci spp. in lone blood culture sets, vancomycin serving as the most prevalent antibiotic administered. In the scope of hospital contamination rates, a total of 409 blood cultures in 2025 were characterized as contaminants, accounting for 2.22% of the total blood culture collections. There was no significant difference in mortality regarding patients that received antibiotics for three days or less when compared to patients that received a duration of antibiotics exceeding three days; however, patients receiving a short duration of antibiotics had a significantly shorter length of stay. Infectious disease consults were ordered in 39 patients, with recommendations for ceasing antibiotic use in 19 of the 39 consults. Costs attributable to contamination events were approximately $107,000 per year for the hospital. The increase in pharmacist workload on vancomycin management for patients with potential contaminations neared 18 pharmacist hours per year.
Conclusions:
Of the patients with CoNS in one of two blood culture sets, vancomycin was the primary agent utilized. The estimated costs attributable to contaminated blood culture sets were primarily driven by laboratory costs. Extended duration of antibiotics did not show improvement in mortality, and shorter treatment durations were associated with overall decreased lengths of stay. Future considerations will be educating on identify potentially contaminated blood cultures, and informing care providers on the outcomes of this study in regards to length of stay and mortality.

Background: Methicillin- resistant Staphylococcus aureus (MRSA) nasal Polymerase Chain Reaction (PCR) screening is an evidenced based diagnostic tool that can guide decisions regarding the need for anti-MRSA therapy. This evaluation aims to assess the correlation between positive nasal PCR results and culture confirmed Staphylococcus aureus infections. The utility of this screening method will be assessed for skin and soft tissue infections (SSTIs), bacteremia, wound, and urine cultures. These findings may help determine if the use of nasal PCR can be expanded beyond pneumonia to serve as a tool for guiding antimicrobial therapy in suspected MRSA infections at our institution.   

Methods: This is a single-center, retrospective study conducted at a 312-bed academic teaching hospital. Hospitalized patients 18 years of age and older who had a positive nasal PCR screening with a corresponding blood, urine, and wound culture outcomes. The primary outcome is to evaluate whether nasal PCR screening demonstrates a predictive value in relation to culture-confirmed Staphylococcus aureus infections. The data will be grouped for each set of cultures and will determine a negative predictive value. The study protocol is designated exempt from review by the Hospital Corporation of America (HCA) Institutional Review Board (IRB).  
 
Results: Based on the blood, urine, and wound culture data, the wound data had the greatest negative predictive value. Overall, 1000 patients were screened, 495 patients were excluded due to the lack of additional body sources. Out of the 505 patients, 52 were excluded due to lacking a blood, urine, or wound culture. There were 453 patients that were then included overall in the data collection. Blood cultures had a negative predictive value of 68.5%, urine cultures 66.1%, and wound cultures 76.2%. 
 
Conclusion: Based on the results from our institution there is correlation that having a negative MRSA Nasal PCR would likely result in negative MRSA/MSSA blood, wound, or urine cultures. The highest NPV was for wound cultures at 76.2%. Further research is needed to assess a larger population and potential impact of antimicrobial agents initiated prior to MRSA Nasal PCR for future studies. 

Background: Daptomycin and ceftaroline combination therapy (combination therapy) has been used as a salvage treatment of persistent methicillin-resistant S. aureus (MRSA) bacteremia for its synergistic effect, with promising clinical data when compared with monotherapy. The ideal duration of combination therapy is currently unclear.


Methods: A retrospective, multi-hospital healthcare system, observational cohort study comparing adult patients with persistent MRSA bacteremia that cleared blood cultures while receiving daptomycin and ceftaroline combination therapy. Patients were grouped into those who received ≤ 7 days of combination therapy after blood culture clearance (short duration group) and those who received > 7 days of combination therapy (long duration group). The primary outcome is a composite of 30-day all-cause mortality and recurrence of MRSA bacteremia. Secondary outcomes include adverse events, 90-day all-cause mortality, 90-day recurrence of MRSA bacteremia, and hospital length-of-stay.


Results: 94 patients were included, with 55 patients in the short duration group and 39 in the long duration group. Within the primary outcome, 10 patients in the short duration group and 7 patients in the long group experienced mortality or MRSA bacteremia recurrence within 30 days of the end of treatment (18.2% vs 18%, p=0.98). The short duration group experienced numerically more 90-day all-cause mortality events than the long duration group (29.1% vs 25.6%, p=0.71). There were similar rates of 90-day MRSA bacteremia recurrence between groups (3.7% vs 2.5%, p=1). The long duration group had a longer median overall hospital length-of-stay (LOS) (40 vs 22 days; p=0.002) and a longer median hospital LOS post-blood culture clearance (13.1 vs 34 days; p=0.001). There was no statistically significant difference in incidence of adverse events. The long duration group had numerically more instances of thrombocytopenia (5.5% vs 18%, p=0.09). Two cases of C. difficile requiring treatment occurred, both in the long duration group.


Conclusions: Among patients with persistent MRSA bacteremia, duration of combination therapy after blood culture clearance had no difference on 30-day mortality or recurrence. Results may help reduce unnecessary antibiotic exposure and hospital length-of-stay.

Abstract 
Title: Cefazolin vs. Clindamycin for Surgical Prophylaxis in Patients with a Beta-Lactam Allergy 
Authors: John Otasowie, Plamen Mangarov, Daniel Rogers, and Mydien Tran 
Background 
About 20% of all healthcare-associated infections are due to surgical site infections (SSIs), representing a substantial clinical and economic burden with an estimated annual cost exceeding $3.3 billion. Despite advances made in infection control practices by the implementation of preoperative prepping and prophylactic antibiotic administration, SSI remains a significant cause of morbidity and mortality. Appropriate use of perioperative antibiotics is imperative to reduce the rate of SSIs. For most procedures, cefazolin is the drug of choice for surgical prophylaxis due to its proven efficacy and safety, a desirable pharmacokinetic profile, an ideal spectrum of activity against commonly encountered organisms during surgery, and a relatively low cost.   
However, penicillin and cephalosporin allergy labels remain a significant barrier to cefazolin use. Approximately 10% of patients report a penicillin allergy, and 2% a cephalosporin allergy. Studies suggest that over 95% of patients labeled with a penicillin allergy do not have an actual immunoglobulin E-mediated allergy and could tolerate penicillin. However, clinicians often utilize alternative agents like clindamycin in the presence of a documented β-lactam allergy. Nevertheless, clindamycin use has been linked to higher rates of SSIs and Clostridioides difficile infection (CDI). Despite these concerns, clindamycin remains a popular prophylactic option for patients labeled with a β-lactam allergy, even when cefazolin may be safely administered. This study evaluated whether patients receiving cefazolin for surgical prophylaxis had comparable outcomes to those receiving intravenous clindamycin in the setting of a documented β-lactam allergy. 
Methods 
This single-center, retrospective cohort study included patients aged 18 years or older with a documented β-lactam allergy who received either cefazolin or clindamycin for surgical prophylaxis between October 1, 2022, and March 1, 2023. Patients were excluded if they received antibiotics for any indication other than surgical prophylaxis, underwent procedures requiring broader prophylaxis, or lacked documentation to assess 30-day post-op outcomes. The primary outcome was the incidence of SSI within 30 days post-surgery. Secondary outcomes included the incidence of CDI within 30 days post-discharge, the 30-day post-discharge rehospitalization rate, the percentage of perioperative anaphylaxis among cefazolin recipients, and the rate of inappropriate clindamycin use based on β-lactam allergy classification per Emory Guidance. Continuous variables were reported as median (interquartile range); categorical variables were reported as frequencies and percentages. Categorical outcomes were compared using Fisher’s exact test or chi-square based on observed cell frequency; statistical significance was defined as p<0.05. 
Results 
A total of 233 patients were included: cefazolin (n=139) and clindamycin (n=94). Baseline characteristics were comparable between groups. The 30-day SSI rate was significantly lower in the cefazolin group compared to clindamycin (0.0% vs. 4.3%, p=0.025). No cases of CDI within 30 days post-discharge were observed in either group. The 30-day rehospitalization rate did not differ significantly between groups (5.0% vs. 6.4%, p=0.773). No perioperative anaphylaxis events occurred among cefazolin recipients. Per institutional β-lactam allergy guidance, 93 of 94 clindamycin recipients (98.9%) had a cefazolin-indicated allergy classification, representing inappropriate clindamycin use; only 1 patient (1.1%) had a true contraindication to cefazolin. 
Conclusion 
Cefazolin demonstrated a statistically significantly lower 30-day SSI rate than clindamycin in β-lactam-allergic patients, with no perioperative anaphylaxis. The absence of CDI and comparable rehospitalization rates further support the safety of cefazolin in this population. Nonadherence to institutional guidance, underscores a substantial stewardship opportunity. These findings support initiatives to reassess β-lactam allergy labels and prioritize cefazolin for surgical prophylaxis in appropriately selected patients. 
 

AUTHORS: Brittany Shellhouse, Eric Shaw, Amy Taylor

BACKGROUND: National Healthcare Safety Network (NHSN) defines a surgical site infection (SSI) as an infection that was not present at time of surgery but occurred within 30 days post-operatively. Due to their significant effect on morbidity, hospital length of stay, and costs, national guidelines recommend initiation of most pre-operative antibiotics within 60 minutes of surgery. They also include specific guidance on the choice of agent to use with the various types of procedures, as well as dosing recommendations and re-dosing strategies. The purpose of this study was to examine if there is a correlation between timing of pre-operative antibiotics on the development of post-operative infections, and to examine other potential risk factors for the development of SSIs.

METHODS: This study was a retrospective, single-center, case-control study, which took place at a level-one trauma academic medical center in the United States. It included adults who received pre-operative antibiotics for colorectal and/or hysterectomy surgeries between January 1, 2023 through September 26, 2025. Patients were excluded if they had infections documented as present at time of surgery, or if they were pregnant or incarcerated at time of admission. The event group included patients with NHSN defined SSIs. The control group was matched 1:1 based on surgery type and consisted of patients who did not have a documented SSI. Patients were identified with assistance from the Infection Prevention Workgroup’s data collection of all surgical procedures.

The primary endpoint compared association of antibiotic timing with incidence of post-operative infection. Secondary outcomes included the comparative risk of antibiotic(s) selection, surgery type, emergent versus scheduled surgery, administration of repeat dosing during surgery, continuation of post-operative prophylactic antibiotics, and personnel present at surgery.

RESULTS: This study included 96 total patients matched 1:1 with events versus controls within each group for hysterectomy, colorectal surgeries, and colorectal plus hysterectomy surgeries (40 patients, 52 patients, and 4 patients respectively). For the primary outcome, the median time of antibiotic start and completion prior to surgery was 23 minutes and 15 minutes for the control group and 15.5 minutes and 9 minutes for the event group.
While all antibiotics selected for hysterectomy procedures were correct per guidelines, there was a numerical difference in optimized dosing for the control versus the event group (85% vs 65% respectively). Similarly, all patients were in compliance with repeat dosing per guidelines, but zero patients in the control group received antibiotics post-operatively compared with 5% of patients in the event group.

Appropriate antibiotic selection for colorectal procedures was 65% versus 54% for the control versus the event group; optimized dosing per guidelines was 67% versus 77% for controls versus event group. There was a numerical difference for control versus event group in required repeat per protocol (91% vs 70%), bowel prep administration (58% vs 19%), and use of post-operative antibiotics (27% vs 58%).
For combination colorectal surgery plus hysterectomy, there was a numerical difference in incidence of emergent surgeries for control versus event group (0% vs. 50%). However, this difference was inverse for antibiotic selection with 50% versus 100% compliance for control versus event group.

CONCLUSION: There was a numerical difference in perioperative timing of antibiotics, but no definitive trend in additional factors for increasing risk of SSI development. Limitations to this study were small sample size and inclusion of only two surgery types. Further research across various surgery types may be beneficial in distinguishing perioperative antibiotic timing.

Title: Micafungin Treatment Failure in Obese Patients: Standard versus Body Mass Index-Adjusted Dosing Regimens

Authors: Helene Gao, Zachary Halbig, Caroline Gresham, Qian Zhong
Piedmont Athens Regional Medical Center - Athens, GA

Background: Obesity (BMI ≥30 kg/m²) affects more than 40% of adults in the United States and is associated with altered pharmacokinetics, creating uncertainty around optimal antifungal dosing. Micafungin, an echinocandin, is commonly used for invasive Candida infections, with standard dosing recommendations of 100-150 mg daily. However, pharmacokinetic and pharmacodynamic studies suggest that higher doses may be necessary in obese patients to achieve adequate drug exposure. Despite these findings, clinical outcome data supporting dose adjustments remain limited. Existing studies have largely been small, model‑based, or lacking comparison groups, leaving the real-world clinical impact of higher micafungin dosing unclear. This study aimed to compare clinical outcomes in obese adults receiving BMI-adjusted micafungin dosing (150-200 mg daily) versus standard dosing, with a primary focus on treatment failure.

Methods: This IRB-exempt, single-center, retrospective study evaluated obese adult patients admitted to Piedmont Athens Regional who received micafungin for ≥3 days as empiric or definitive antifungal therapy. The BMI-dose-adjusted group consisted of 19 randomly selected patients admitted between October 1, 2020, and October 30, 2025, with a cohort of 19 obese patients receiving standard micafungin dosing. Exclusion criteria included outpatient micafungin initiation, missing weight data, dose changes after ≥2 days, or <3 days of therapy. Data collected included demographics, comorbidities,infection‑related risk factors, key laboratory values, and micafungin treatment characteristics. Clinical variables evaluated included critical‑care interventions, hemodynamic support, and the presence of polymicrobial infection. The primary outcome was treatment failure, defined as all‑cause inpatient mortality or transition to comfort care before discharge. Secondary outcomes included micafungin duration, total hospital length of stay, and occurrence of adverse drug events involving hepatic, renal, or hematologic function. Categorical variables were analyzed using Chi‑squared or Fisher’s exact testing as appropriate, and continuous variables were analyzed using the Mann‑Whitney U test. A multivariable logistic regression was performed to adjust for confounders.

Results: Unadjusted outcomes revealed that treatment failure occurred in 36.8% of patients in the BMI-adjusted group and 42.1% in the standard-dose group (OR=1.25, 95% CI=0.34-4.59; p=0.74). The median duration of micafungin therapy was 5 days in the BMI-adjusted group and 7 days in the standard-dose group (p=0.12), while median hospital length of stay was 16 versus 23 days, respectively (p=0.11). Adverse drug reactions occurred in 36.8% of BMI-adjusted patients and 26.3% of standard-dose patients (p = 0.49). After adjusting for confounders, including SOFA score, number of comorbidities, and polymicrobial infection, there was a trend toward fewer treatment failures in the BMI-adjusted dosing group (OR=0.22, 95% CI=0.03-1.58;p=0.13). Within the observed range of SOFA scores, each 1-point increase within 24 hours of micafungin initiation was associated with approximately 40% increased odds of treatment failure (OR=1.40, 95%CI=1.12-2.47; p=0.002). In exploratory subgroup analyses, BMI-adjusted dosing was associated with 45% lower odds of treatment failure in ICU patients (OR=0.55, 95% CI=0.12-2.47; p=0.43) and 44% lower odds in patients with candidiasis (OR=0.56, 95% CI=0.07-4.76; p=0.59).

Conclusions: In obese adults receiving micafungin, BMI-adjusted dosing was not associated with a statistically significant difference in treatment failure compared with standard dosing. However, accounting for confounders, the analysis demonstrated numerically lower odds of treatment failure with BMI-adjusted dosing, with only SOFA score remaining significantly associated with treatment failure. Furthermore, exploratory subgroup analyses showed a consistent directional association favoring BMI-adjusted therapy. Limitations include the retrospective design, small sample size, and limited power to detect differences in outcomes. Larger, prospective studies are warranted to further evaluate the clinical effectiveness and safety of BMI-adjusted micafungin dosing, particularly in ICU patients.

Authors: Jada R. Guilford, PharmD; Taylor J. Merritt, PharmD; Sarah B. Green, PharmD, BCIDP, AAHIVP; Sujit Suchindran, MD, MPH; Benjamin Albrecht, PharmD, BCIDP; Emory University Hospital, Atlanta, GA  

Background: For more than 60 years, Vancomycin has been used to treat a variety of infections due to gram-positive organisms. Vancomycin has the potential to be nephrotoxic and ototoxic, subjecting patients to possible adverse events, and requires frequent monitoring to ensure appropriate use, increasing healthcare costs. Clinical guidelines currently recommend utilizing the ratio of 24-hour area under the curve (AUC) to minimum inhibitory concentration (MIC) for as the therapeutic target for dosing and monitoring, as this method improved patient outcomes in methicillin-resistant Staphylococcus aureus (MRSA) infections by ensuring adequate drug exposure while minimizing side effects. Currently, target AUCs range from 400-600 mg*hour/L for MRSA infections, assuming an MIC of ≤1 mg/L; however, there is limited data to support an AUC-based dosing strategy for non-MRSA gram-positive bloodstream infections. The purpose of this study is to assess the differences in select patient outcomes, particularly mortality and adverse events, by comparing time to blood culture clearance in patients with a vancomycin AUC ≥ 400 mg*hour/L and those with AUC <400 mg*hour/L within 5 days of therapy for non-Staphylococcus aureus and non-Staphylococcus lugdunensis gram-positive bloodstream infections.
Methods: This is an Institutional Review Board (IRB)-approved, single center, retrospective observational study. Patients were included if they were 18 years or older with a blood culture positive for a non-Staphylococcus aureus or non-Staphylococcus lugdunensis gram-positive organism and received IV vancomycin between May 1, 2024 and April 22, 2025. Patients were also included if they received ≥120 hours of vancomycin, had at least 1 vancomycin level, and vancomycin was still included in the antimicrobial regimen within 48 hours of culture clearance. Patients were excluded if the vancomycin indication was CNS infection, osteomyelitis, or endocarditis or if they did not meet the criteria for use of the Emory Healthcare AUC dosing protocol: on hemodialysis, peritoneal dialysis, or CRRT, had an acute kidney injury (AKI), weight >250 kg or BMI <20 kg/m2, or a peri-operative indication.
Results: A total of 55 patients met inclusion criteria, including 32 patients with an AUC <400 mg*hour/L and 23 patients with an AUC ≥400 mg*hour/L. There was no difference in the primary outcome of time to blood culture clearance between groups. The average time to blood culture clearance was 34.7 hours for AUC <400 and 37.1 hours for AUC ≥400 (p=0.515). More patients in the AUC ≥400 mg*hour/L group experienced acute kidney injury, but this difference was not statistically significant (17.4% vs 3.1%, respectively). Toxicity is typically seen in AUC > 650 mg*hour/L, and median AUC for each group was 293 mg*hour/L and 519 mg*hour/L respectively. There were no incidences of ototoxicity and one case of inpatient mortality in both groups. Inpatient length of stay was a median of 11 days (IQR 7-21.5) for AUC <400 mg*hour/L and 27 days (IQR 9-43.5) for AUC ≥400 mg*hour/L.
Conclusions: Both AUC groups had similar times to blood culture clearance without significant rates of adverse events or all-cause mortality.  Lower AUCs were associated with decreased length of stay; however, due to low rates of adverse events, and no matching for acuity beyond exclusion, this difference may not be related directly to different AUCs.

Title: Comparative Outcomes of Oral Beta-Lactams Versus Fluoroquinolones or Trimethoprim-Sulfamethoxazole for Step-Down Therapy in Enterobacterales Bacteremia Secondary to Urinary Tract Infections

Primary: Taylor Hewitt
Secondary: Jordyn Meredith, Joseph Crosby, Courtney Zeigler

Background: This single-center, retrospective, observational cohort study was conducted at St. Joseph’s/Candler Health System to assess treatment failure in patients with Enterobacterales bacteremia secondary to urinary tract infections (UTIs) who received oral step-down antibiotic therapy. The study included patients hospitalized between January 1, 2022, and August 1, 2025, identified using ICD-10 codes for bacteremia. Electronic medical records were reviewed to confirm infection from a urinary source, requiring matching positive urine and blood cultures for Escherichia coli, Klebsiella spp., or Proteus spp. Eligible patients were adults (≥18 years) who received parenteral antibiotics during admission, followed by oral step-down therapy with either a beta-lactam, fluoroquinolone (FQ), or trimethoprim-sulfamethoxazole (TMP-SMX). Exclusion criteria included polymicrobial bacteremia, absence of oral step-down therapy, discharge to hospice, or pregnancy. Patients were stratified into two groups: those who received oral beta-lactams versus those who received FQ or TMP-SMX. The primary outcome was treatment failure, defined as a recurrent positive urine or blood culture for the same organism within 60 days of the initial diagnosis. The secondary outcomes included duration of therapy (both parenteral and oral), and hospital length of stay. Descriptive statistics summarize baseline characteristics and outcomes. Continuous variables were analyzed using Student’s t-test, and categorical variables using chi-square tests or appropriate non-parametric alternatives. Analyses were performed using Microsoft Excel, with statistical significance defined as a two-sided p-value < 0.05.

Results: Thirty-eight patients were enrolled in this study, including 11 patients who received oral beta-lactams and 27 patients who received fluoroquinolones (FQ) or trimethoprim-sulfamethoxazole (TMP-SMX). The primary outcome of treatment failure occurred in 7 patients (64%) from the beta-lactam group and 1 patient (4%) from the FQ/TMP-SMX (p=0.00004). No significant difference was found between the two groups for secondary outcomes duration of therapy and hospital length of stay.

Conclusion: In this study assessing treatment failure in patients with Enterobacterales bacteremia secondary to urinary tract infections (UTIs) who received oral step-down antibiotic therapy, a higher percentage of patients experienced treatment failure in the beta-lactam group compared to the FQ/TMP-SMX group.  The secondary outcomes of length of hospital stay and duration of therapy were similar across both groups. Potential limitation factors include inability to assess adherence to antibiotic therapy outpatient and step-down to oral therapy occurring at different points within the hospital stay. Future studies should target a larger population with only in-patient stepdown therapy due to the traceability of patients receiving antibiotics.

Title: Effectiveness of Amoxicillin-Clavulanate for the Treatment of Extended-Spectrum β-Lactamase-producing Enterobacterales (ESBL-E) Urinary Tract Infection

Author: Haseeb Ahmed, Nicholas Rosen, Ryan Tilton, Olivia Randazza, John Williamson, Charles Hartis, Michael E DeWitt, Alexandria Taylor, Jennifer J Wenner, Mary Banoub

Background: Urinary tract infections (UTIs) are among the most common bacterial infections worldwide, with Enterobacterales being the predominant pathogens. The rise in prevalence of extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) has led to increased antimicrobial resistance and recurrence rates. This prompts evaluation of alternative treatments such as amoxicillin-clavulanate, in which clavulanate may restore amoxicillin activity against common ESBL enzymes. The IDSA 2024 Antimicrobial-Resistant Gram-Negative guidelines recommend against its use but fail to cite high-quality evidence studying its efficacy in UTI caused by ESBL-E. Other studies, limited by small sample size, suggest clinical efficacy of amoxicillin-clavulanate in the treatment of UTI caused by ESBL-E. This study attempts to bolster the pool of data showing amoxicillin-clavulanate can be as effective as standard of care (SOC) antibiotics for treatment of UTI caused by ESBL-E.

Methods: This multi-site, retrospective cohort study is approved by the Institutional Review Board. Adult patients (≥18 years) with either uncomplicated or complicated UTI with a urine culture positive for ESBL-E (confirmed with susceptibility testing) treated between April 1, 2024, and July 1, 2025, at Atrium Health Wake Forest Baptist facilities were included. Patients must have received at least 72 hours of amoxicillin-clavulanate or SOC therapy. Patients were excluded if they had concurrent bacterial infections, polymicrobial urine cultures, a previous UTI within 90 days already captured in the dataset, anatomic urinary tract abnormalities or instrumentation, renal abscesses, prostatitis, receive in-vitro active antibiotic lead-in therapy for >50% of treatment duration, were immunosuppressed or use methenamine or antibiotics for prophylaxis. The primary endpoint is clinical failure within 90 days, defined as retreatment with antibiotics and either recurrence of UTI symptoms or a repeat urine culture positive for the same organism as the index infection. Secondary endpoints include time to clinical failure and recurrence of resistant organisms (carbapenem-resistant Enterobacterales, SOC-resistant, or amoxicillin-clavulanate-resistant strains) within 90 days. Chi-square or Fisher’s exact tests tested categorical variables, and t-tests or Mann-Whitney U tests will test continuous variables. Kaplan-Meier survival analysis and Cox regression modeling will assess time-to-event outcomes, and multivariable analysis will be used to identify patient factors associated with clinical failure.

Results: A total of 447 patients were screened, of whom 274 patients met inclusion criteria and were analyzed. Fifty-four patients were included in the amoxicillin-clavulanate group, while 220 patients were included in the SOC group. No statistically significant difference was observed in the primary outcome of treatment failure between the SOC and amoxicillin-clavulanate groups (p = 0.11). Patients with prior history of ESBL infection had more than twice the odds of treatment failure (OR 2.09; p = 0.04), a finding that remained significant after adjustment for antibiotic selection and type of UTI (OR 2.11, p = 0.047). Additionally, the use of sulfamethoxazole-trimethoprim for treatment of the index infection was associated with an 82% reduction in clinical failure compared to amoxicillin-clavulanate (p = 0.01).

Conclusions: Among patients treated with antibiotics for urinary tract infection caused by ESBL-producing Enterobacterales species, we were unable to detect a difference in treatment failure within 90 days between amoxicillin-clavulanate and SOC. This indicates that within the limits of this study, amoxicillin-clavulanate may have comparable effectiveness to other agents used to treat urinary tract infections caused by these resistant organisms.

Background/Purpose: Antimicrobial-resistant organisms are a growing public health threat and contribute to increased morbidity and mortality, longer hospital stays, and higher healthcare costs. In particular, the utilization of anti-pseudomonal beta-lactam antibiotics significantly contributes to the development of resistance in addition to increasing the risk of complications such as Clostridioides difficile infections. The purpose of this study is to review and evaluate the effectiveness and safety of empiric cefepime and piperacillin/tazobactam de-escalation through an implemented Pseudomonas aeruginosa risk stratification tool utilized by the antimicrobial stewardship team.  

Methodology: This study is a single-center, retrospective cohort study including patients admitted to St. Francis Hospital Downtown from January 2025 to August 2025. Data for this study was obtained from the electronic medical record, which includes clinical, pharmaceutical, and laboratory information. Patients were identified via antimicrobial stewardship intervention notes for P. aeruginosa risk stratification. The primary outcome sought to elucidate effectiveness, defined as re-escalation of antibiotics due to infectious cause or clinical deterioration. Secondary outcomes were centered around safety, defined as total days of antimicrobial therapy, development of Clostridioides difficile infection, readmission rate within 90 days, and NHSN Standardized Antimicrobial Administration Ratio (SAAR) data pre and post intervention. Patients were included in this study if they had an active order for cefepime or piperacillin/tazobactam, are 18 years of age or older, and have documentation of completed screening by the antimicrobial stewardship team. Patients were excluded if they had positive microbiological results at the time of audit before de-escalation by the antimicrobial stewardship team, duplicate patients, or de-escalation not pursued. The impact of antimicrobial stewardship intervention on the utilization and de-escalation rates of antipseudomonal beta-lactam antibiotics were evaluated using descriptive statistics. 

Results: A total of 523 patients were screened for inclusion, of which 278 were included in the analysis for the primary and secondary outcomes. The most frequent indication prompting anti-pseudomonal beta-lactam de-escalation was intra-abdominal infection (104/278, 37.4%). The mean duration of broad-spectrum anti-pseudomonal beta-lactam therapy prior to intervention was 2 days (SD 1.95). The total number of days on de-escalated therapy was 751 versus the total days of anti-microbial therapy (de-escalated + initial + re-escalated) was 1513 days. For the primary endpoint, 15 patients (15/278, 5.4%) required re-escalation of anti-microbial therapy. The most common regimen used for de-escalation was ceftriaxone plus metronidazole (104/278, 37.4%). The most common reason for re-escalation was suspected worsening infection or clinical deterioration (13/15, 86.7%), and the most frequently used medication for re-escalation was piperacillin/tazobactam (8/15, 53.3%). Regarding the secondary endpoint of safety, 1 patient developed Clostridioides difficile infection after intervention. Additionally, 106 patients (106/278, 38%) were readmitted within 90 days from initial admission.  

Conclusion: Based on the primary outcome findings, empiric de-escalation of anti-pseudomonal beta-lactams using risk stratification appears to be effective, as only a small proportion of patients (5.4%) required re-escalation of antimicrobial therapy. These results are consistent with previous studies demonstrating that patients without risk factors for Pseudomonas aeruginosa are unlikely to have infection with this organism and therefore be appropriately managed with narrower spectrum antimicrobial therapy. Regarding secondary outcomes, only one patient developed Clostridioides difficile infection following de-escalation. However, a relatively high readmission rate (38%) within 90 days from initial admission was observed. This may be attributed to factors such as inadequate source control and re-escalation of antibiotics initiated in the emergency department and continued during subsequent admissions. Future investigations evaluating further de-escalation beyond ceftriaxone may be warranted, given its relatively broad spectrum of activity compared to other antimicrobial options.

Authors: Emily Gunselman; Linda Johnson; Rachel Anderson; Bradley Proctor


Background/Purpose: Asymptomatic bacteriuria (ASB) is defined as “the presence of one or more species of bacteria growing in the urine at specified quantitative counts (>105 colon-forming units [CFU]/mL or >108 CFU/L), irrespective of the presence of pyuria, in the absence of signs or symptoms attributable to urinary tract infection (UTI).”.1 Urinary tract infections (UTIs) are a clinical syndrome that should be diagnosed based on symptoms such as dysuria, urgency, frequency, suprapubic pain, flank pain, and costovertebral angle tenderness  with or without systemic signs of infection such as fever, chills, rigors or hemodynamic instability.2 The Infectious Diseases Society of America (IDSA) recommends against screening for and treating ASB, except in pregnant patients or prior to a planned urologic procedure.1 Treating ASB in patients, aside from the aforementioned exceptions, has shown lack of benefit and has also lead to increased risk of harm including: development of symptomatic UTI, colonization with multi-drug resistant gram negative rods, and increased risk of developing Clostridiodes difficile infection (CDI).3,4,5 The Emergency Department (ED) is the most common location for the ordering of urine cultures and early treatment for a suspected UTI. In August of 2025, CHI Memorial Hospital approved an Expected Practice document providing leadership support to not treat ASB.6 Additionally, a guidance document on the management of UTIs was created which detailed empiric treatment recommendations with regards to drug, route, dose, and duration based on national guidelines as well as local antibiogram data for both patients discharging from the ED and those being admitted. Didactic education was provided to the ED clinicians and the guidance documents were made available. The goal of this project was to evaluate appropriateness of ED antibiotic use for ASB and suspected urinary tract infections pre- and post- stewardship intervention. 


Methods: This is a single-center, IRB approved, quasi-experimental study. Adult patients seen in the ED with positive urine cultures showing a uropathogen were included. Patients were excluded if they had an outpatient diagnosis of UTI, another suspected source of infection, or neutropenic fever. The primary outcome of this study is to evaluate the appropriateness of empiric antibiotic therapy pre- and post- intervention. Secondary outcomes include safety of intervention, new positive cultures showing resistant organism growth, CDI, and re-presentation to the ED with the same diagnosis within 30 days.

Results:
Primary Outcome: Appropriateness of empiric antibiotic treatment choice for UTI did not improve post-intervention. However, the number of patients who had ASB and received antibiotics did decrease post-intervention.
Secondary Outcomes: There was no shown difference in development of symptomatic UTI, development of CDI, or re-presentation to the ED within 30 days for the same diagnosis between patients that were appropriately treated vs not. However, more patients developed new resistant organism growth in subsequent urine cultures in the group of patients that were not appropriately treated.
No values were found to be statistically significant.

Conclusion: 

• The educational intervention was not effective at guiding provider empiric antibiotic choice in the ED

• ASB was often treated in the pre- and post-intervention periods

• The expected practice document was not an effective tool in altering clinical behavior in the ED

Title:
Daptomycin Combination Therapy with Ceftaroline versus Anti-Staphylococcal Beta-Lactams for the Treatment of Persistent Methicillin-Resistant Staphylococcus aureus Bacteremia

Authors:
Christopher Staten, PharmD
Kelvin Gandhi, PharmD, BCIDP
Lindsey Moeller, PharmD, BCPS

Background:
Persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is poorly defined and not well established; recent literature characterizes it as a bloodstream infection with ongoing positive blood cultures for two or more days despite receipt of targeted therapy against MRSA. Persistent bacteremia may occur in up to 39% of S. aureus bacteremia cases, and has been associated with increased mortality, risk of metastasis, and incidence of microbiologic relapse. Traditional pharmacotherapy includes either vancomycin or daptomycin, however when persistent MRSA bacteremia is present, synergistic therapy is oftentimes explored to assist in microbiological eradication. Combination therapies of beta-lactams with daptomycin are currently being clinically evaluated due to their theorized enhancement of daptomycin binding based on data from in vitro studies. Beta-lactam synergy with daptomycin may increase depolarization of the bacterial cell wall to improve daptomycin efficacy and bactericidal activity. Despite strong in vitro data, the in vivo data is inconsistent when demonstrating impact on clinical outcomes. Ceftaroline is most commonly utilized in clinical practice as the synergistic adjunctive agent of choice with daptomycin due to its strong in vitro data, however it is more costly compared to other studied adjunctive agents such as anti-staphylococcal beta-lactams (ASBL).

Methods: 
This was a retrospective multicenter cohort study that included hospitalized adult patients with at least one blood culture positive for MRSA from September 1, 2022 to October 31, 2025 at AdventHealth East Florida Division hospitals. Patients were allocated into two groups, either daptomycin plus ceftaroline (DPT/CFT), or daptomycin plus an ASBL (DPT/ASBL), which included cefazolin and oxacillin. Patients were included if they received 72 hours of combination therapy in either group. Excluded patients were those under 18 years of age, pregnant, or received less than 72 hours of combination therapy. The primary outcome was composite clinical failure; composed of 60-day mortality, 60-day recurrence, and persistent bacteremia at day five of combination therapy. A non-inferiority threshold was set at 10.0% based on incidence rates demonstrated by pertinent literature. A multivariate logistic regression was performed on the primary outcome to assess possible confounding variables.

Results: 
A total of 53 patients were investigated in this study, 41 in DPT/CFT and 12 in DPT/ASBL. The primary outcome of composite clinical failure was met in 13 (31.7%) in the DPT/CFT group and 3 (25.0%) patients in the DPT/ASBL group (ARD 6.71). The difference of 6.71% did reach the threshold set for non-inferiority of 10% difference. A multivariate logistic regression analysis showed no statistically significant associations identified for the primary outcome by ICU admission, Charlson Comorbidity Index (CCI), time to source control, and duration of combination therapy.

Discussion:
This retrospective analysis comparing daptomycin plus ceftaroline (DPT/CFT) to daptomycin plus ASBL (DPT/ASBL) for persistent MRSA bacteremia, demonstrated that DPT/ASBL was non-inferior to DPT/CFT. Of note, patients in the DPT/CFT arm were generally more critically ill; though not reflected in the differences in APACHE II score, CCI, or Pitt Bacteremia Score, they had more complicated sources of infection, higher ICU admission rates, and increased clinical instability, potentially impacting outcomes.

Conclusion: 
Nonetheless, our findings ultimately suggest that DPT/ASBL combination may be an alternative regimen to DPT/CFT in a select clinical context. This combination could provide an alternative option for persistent MRSA bacteremia, but prospective studies are needed to better define the comparative clinical efficacy and safety in different patient populations.

Oral Beta-lactam (BL) Versus Fluoroquinolone (FQ) or Sulfamethoxazole-Trimethoprim (SMXTMP) in Uncomplicated Gram-Negative Bacteremia (uGNB) Jared Robbins, Tyler Baumeister, Tracey Bastian Williamson Medical Center - Franklin, TN

Background/Purpose: Gram negative bacteremia is associated with significant morbidity and mortality. Historically, uncomplicated gram-negative bacteremia (uGNB) has been treated with highly bioavailable oral options like fluoroquinolones (FQ) or sulfamethoxazole/trimethoprim (SMX-TMP). This is primarily due to pharmacokinetic concerns and questionable bioavailability of other agents such as beta-lactam (BL) antibiotics. Therefore, optimal oral step-down agents for uGNB remains highly debated. The unfavorable safety profiles of FQs and SMX-TMP have sparked interest in investigating safer alternatives. Current literature including systematic reviews, meta-analyses, and cohort studies suggest beta-lactams may be an efficacious and safe alternative for uGNB. This study aims to compare the efficacy and safety of BLs versus FQs/SMX-TMP for oral step-down therapy in uGNB in a community hospital setting.

Methodology: This was a single-center, IRB-approved, retrospective study conducted at a 337- bed hospital in Franklin, Tennessee that evaluated clinical failure rates of 100 patients receiving either BLs or FQs/SMX-TMP for the treatment of uGNB. Eligible patients admitted between August 1, 2023, and August 1, 2025, who met inclusion and exclusion criteria were identified for analysis. Baseline characteristics included age, sex, weight, Charlson comorbidity score (CCS), and PITT bacteremia score. The primary outcome was a composite of clinical failure, defined by having 1 of the following; 30-day hospital readmission due to antibiotic intolerance, 30-day recurrent bacteremia caused by the same microorganism, or escalation in therapy. Secondary outcomes included individual components of the primary outcome at 90 days, 90-day incidence of Clostridioides difficile infection (CDI), duration of therapy (summative and breakdown components of IV/PO groups), and hospital length of stay. Safety outcomes included rates of hyponatremia, acute kidney injury, and hyperkalemia as primary cause of re-admission at 30 and 90 days, and a composite of these components.

Results: This trial included 100 total patients, 58 designated in the BL group, and 42 designated in the FQ/SMX-TMP group. Baseline characteristics were comparable between groups, with the exception of age (78.8 years vs 71.3 years, in the BL vs FQ/SMX-TMP groups, respectively; p=0.004) and CCS (5.2 vs 4.2, in the BL vs FQ/SMX-TMP groups, respectively; p=0.04). The primary outcome of 30-day composite clinical failure occurred in 4/58 patients (6.9%) in the BL group, and 4/42 patients (9.5%) in the FQ/SMX-TMP group. (RR 0.72; CI 0.19-2.73; p=0.72). For secondary outcomes, the 90-day clinical failure composite outcome occurred in 3/58 (5.2%) of patients in the BL group, and 4/42 (9.5%) in the FQ/SMX-TMP group. (RR 0.54; CI 0.13-2.3; p=0.449). Average length of stay, IV antimicrobial duration, and oral antimicrobial duration were similar between the two treatment groups. CDI did not occur in either treatment group. The 90-day composite safety outcomes occurred in 0/58 (0%) patients in the BL group, and 2/42 (4.8%) in the FQ/SMX-TMP group (RR 0.15; CI 0.007-3.02; p=0.174). Of the two events in the FQ/SMX-TMP group, both were due to hyponatremia leading to re-admission and occurred within 30 days post-discharge.

Background: Acute pyelonephritis is a common and potentially serious bacterial infection of the upper urinary tract that frequently results in emergency department (ED) visits and hospitalizations. The most recent Infectious Diseases Society of America (IDSA) guidelines for the management of complicated urinary tract infections (cUTI), include levofloxacin, ciprofloxacin, and sulfamethoxazole-trimethoprim as first line options. Rising antimicrobial resistance among Enterobacterales rases concern for their effectiveness. Thus, clinicians often turn to oral beta-lactams. While well tolerated, their efficacy for pyelonephritis is less established due to lower renal tissue concentrations and variable oral bioavailability. However, recent evidence indicates favorable outcomes with oral beta-lactams. 
Additionally, given the increasing prevalence of extended-spectrum beta-lactamases (ESBLs), understanding the impact of antibiotic selection on the development of future resistance is essential to optimizing antibiotic selection.  
This study aimed to evaluate the comparative effectiveness and downstream resistance outcomes of oral beta-lactam therapy versus first-line agents for the treatment of acute pyelonephritis among adults discharged from the ED. 
 
Methodology: This was a multi-site, retrospective, observational cohort study comparing clinical outcomes and the emergence of ESBL organisms in patients treated for pyelonephritis using first-line agents versus beta-lactam antibiotics. Patients 18 years or older with an ICD-10 code diagnosis of pyelonephritis, a positive urine culture, and an outpatient antibiotic prescription for at least 7 days during the study period from April 1, 2024, to July 8, 2025, were included. Patients were excluded if they had polymicrobial cultures, prior ESBL-producing organism within 3 months, more than one dose of intravenous antibiotics, diagnoses of prostatitis, orchitis, epididymitis, or pregnancy, and patients requiring change of prescription from index visit. The primary outcome was rate of treatment failure within 30 days of the initial ED visit; secondary outcomes included antibiotic selection, dosing, duration, and rates of ESBL emergence.  
Data collection included baseline characteristics such as age, sex, comorbidities, and urine culture resistance patterns within 3 months prior to the ED visit. Statistical analysis was conducted using Pearson’s Chi-squared tests for categorical variables, Student’s t-tests for continuous variables, and univariate regression for association between antibiotic choice and treatment failure. 
Results: A total of 1,396 patients were included in the study between April 2025 and July 2025, 792 patients in the beta-lactam and 604 in the first-line therapy group. The most common reason for exclusion was a change in antibiotic therapy following identification of resistance to the initial agent. 
Patient characteristics and demographics were well balanced between the groups. Most patients were female (89%), non-Hispanic or Latino (78%), and 46% received intravenous antibiotics in the emergency department. The most frequently identified baseline pathogen was Escherichia coli (74%), followed by Klebsiella species (7.6%). 
The primary outcome, treatment failure, occurred in 78 patients (5.6%), including 53 (6.7%) in the beta-lactam group and 25 (4.1%) in the first-line group (p = 0.040). Guideline appropriate dosing was observed in 477 patients (64%) in the beta-lactam group compared to 571 patients (99%) in the first-line group (p < 0.001). Cefdinir was prescribed 142 (10.8%) times but is not recommended in the IDSA guidelines for pyelonephritis. The most frequently guideline non-compliant therapy was cephalexin, which was appropriately dosed in only 38% (14/68) of cases. ESBL emergence was rare, occurring in 5 patients (0.4%), with 4 cases in the beta-lactam group and 1 case in the first-line group (p = 0.4). 
Conclusions: Treatment failure was more frequent in the beta-lactam group.  This finding is potentially attributable to inappropriate antibiotic selection and suboptimal dosing. Specifically, the overuse of cefdinir and underdosing of cephalexin likely contributed to these treatment failures. Additionally, our investigation did not demonstrate a significant association between antibiotic choice and the development of ESBL. 

Background

A significant portion of hospitalized adults presenting to a hospital may require treatment with broad spectrum antibiotics. Cases involving suspected infections and sepsis are frequent occurrences in which empiric antibiotic use is warranted. Vancomycin and piperacillin/tazobactam (pip/tazo) comprise a widely used antibiotic regimen incorporating a glycopeptide antibiotic and a β-lactam/β-lactamase inhibitor respectively. This regimen provides broad-spectrum activity against Gram-positive, Gram-negative, and anaerobic pathogens including methicillin resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. The aim of this study is to determine the relationship between differing doses of pip/tazo and the incidence of AKI in patients treated with concomitant vancomycin and pip/tazo. By identifying whether higher doses of pip/tazo are associated with increased AKI rates, this research seeks to inform antimicrobial stewardship efforts and optimize patient safety while preserving therapeutic efficacy.

Methods

This retrospective cohort study was conducted to assess the impact of different piperacillin/tazobactam dosing regimens on the incidence of nephrotoxicity for patients receiving concomitant vancomycin therapy. The research site for this study is a 700-bed, not-for-profit, public hospital system in a rural Georgia. In March 2024, the site for this study changed protocol regarding piperacillin/tazobactam administration from 3.375gm to 4.5gm IV extended-infusion. Patients receiving concomitant vancomycin and piperacillin/tazobactam were split into 2 groups based on which piperacillin/tazobactam dosing regimen they received. The Institutional Review Board at the research site approvedwill review the methodology of this study for approval prior to any patient data collection.

Results - Vancomycin + Piperacillin/Tazobactam 3.375g ( n=105): 13 (12.4%) experienced AKI.
                Vancomycin +Piperacillin/Tazobactam 4.5g ( n=105) : 16 (15.2%) experienced AKI. 
                 p-value = 0.55


Conclusion - Currently, there is not evidence to suggest that the change in piperacillin/tazobactam extended infusion dosing at the primary site had an impact on nephrotoxic risk for patients being treated with concomitant VPT therapy.

Outcomes Associated with Early Versus Late Infectious Disease Consult for Staphylococcus aureus Bacteremia

Authors: Peyton Johnson, Alanna H. Rufe, Adam Harnden, Nancy Bailey, Sarah Vines, W. Creed Carleton

Purpose: Staphylococcus aureus is the most common Gram-positive cause of bacteremia and is a serious infection with up to 30% mortality. Optimal management of Staphylococcus aureus bacteremia (SAB) includes timely source identification, repeat blood cultures, echocardiography, and appropriate antimicrobial therapy. Infectious disease (ID) consultation is recommended as it is associated with improved patient outcomes, with some literature correlating earlier consultation with even better outcomes. At Jackson Hospital and Clinic most patients with SAB receive an ID consult, but the timing is variable. This study evaluated how timing of ID consultation impacts outcomes for patients with SAB.

Methods: This was an institutional review board approved, retrospective chart review at a 344-bed community hospital in Montgomery, Alabama. Adult patients were included if they had a diagnosis of SAB and received an ID consultation between October 1, 2023, and March 31, 2025. Patients were identified via a clinical decision support tool that reported blood cultures growing Staphylococcus aureus. Key exclusions included polymicrobial bacteremia, expiration within 72 hours of index blood culture, or refusal of treatment. Patients were stratified into two cohorts: early consult (ID consultation < 4 days from SAB diagnosis) and late consult (> 4 days).
The components of the primary composite endpoint were source identification, follow-up blood cultures, echocardiography within 5 days, administration of optimal parenteral antistaphylococcal therapy, and adherence to recommended treatment durations. Secondary endpoints included length of stay, in-hospital mortality, 30-day readmission, acute kidney injury, duration of inpatient antimicrobial therapy, and source-control procedures. Baseline demographics, comorbidities, and methicillin-resistant Staphylococcus aureus incidence were extracted. A priori power analysis estimated 88 patients to achieve 80% power. Additional statistical tests were used as appropriate.

Results: A total of 153 patient encounters were reviewed, and 93 patients met inclusion criteria. Among the included patients, 63 patients received an early infectious disease consultation, while 30 patients received a late consultation. Patients were excluded in the absence of ID consultation, polymicrobial bacteremia, death within 72 hours of admission, discharge against medical advice, and duplicate encounters. Baseline characteristics were similar between the early and late consultation groups, including age (60.3 vs 63.1 years), percentage of male patients (65% vs 63.3%), and incidence of methicillin-resistant Staphylococcus aureus (55.6% vs 56.7%).
Mean time to ID consultation was 1.9 days in the early group compared with 4.8 days in the late group (p < 0.0001). The primary composite quality-of care endpoint was achieved in 62% (n = 39/63) of the patients in the early consultation group compared with 53% (n = 16/30) in the late consultation group (p = 0.58). Acute kidney injury occurred significantly less frequently among patients who received early consultation (9.5% vs 33.3%, p = 0.01). No significant difference was found in length of stay, in-hospital mortality, 30-day readmission, duration of antimicrobial therapy, or source-control procedures between groups.

Conclusion: In this retrospective study of 93 patients with Staphylococcus aureus bacteremia, early ID consultation was not associated with a statistically significant improvement in the composite quality-of-care endpoint compared with later consultation. This may be due to an overestimation of the effect size. Early ID involvement was associated with a significantly lower incidence of acute kidney injury, which may support quality initiatives to standardize ID involvement. Implementing an automatic ID consult at the time initial blood cultures identify Staphylococcus aureus may reduce variability in quality-of-care and should be evaluated in future research.

Title: Association between Enterococcal Infective Endocarditis following a Transcatheter Aortic Valve Replacement
Authors: Felipe Gómez; Caren Azurin; Stefanie Pappas
Affiliation: Ascension Saint Thomas Hospital West, Nashville, TN
Introduction Transcatheter aortic valve replacement (TAVR) is standard therapy for severe aortic stenosis. A severe complication is infective endocarditis (IE), predominantly caused by Enterococcus species (historically 24–34% of cases) due to patient comorbidities and groin contamination during transfemoral access. Our institution’s current prophylaxis protocol utilizes cefazolin, which lacks enterococcal coverage. The primary objective was to assess the association between surgical antibiotic prophylaxis and enterococcal IE risk following TAVR. Secondary objectives evaluated the time to infection, all-cause inpatient mortality, and surgical intervention rates.
Methods A single-center, retrospective observational review was conducted on 102 patients (≥18 years) who underwent TAVR between January 2023 and December 2024. Exclusions included prior antibiotic therapy, concurrent infections, or incarcerated status. Data was collected via REDCap. Statistical analysis utilized Fisher’s exact test for categorical variables and the Mann-Whitney U test for continuous data, with significance defined as p<0.05.
Results Of the 102 patients evaluated, 5 (4.9%) developed IE. Enterococcus spp. was the predominant pathogen, responsible for 80% (4 of 5) of cases. All patients who developed IE received 2 grams of cefazolin prophylaxis. Consequently, no significant association was found between prophylactic choice and IE (p=1.000) due to the near-universal administration of cefazolin. The mean time from surgery to enterococcal IE onset was 497.8 days. The infection rate was 6.4% for transfemoral access versus 0% for the carotid approach (p=0.585). Among the patients who developed IE, mortality was 0%, while 40% (n=2) required surgical intervention.
Discussion & Conclusion Enterococcus caused 80% of TAVR-related IE cases in this cohort, significantly exceeding historically reported rates. The data indicates that current institutional prophylaxis with cefazolin leaves a critical coverage gap for this specific population. Additionally, the higher infection rate in the transfemoral group highlights the risk of groin-sourced enterococcal inoculation. Despite limitations surrounding sample size and retrospective design, these findings provide actionable clinical evidence supporting the revision of the institutional TAVR protocol to incorporate agents with enterococcal activity (e.g., ampicillin/sulbactam) to target the predominant pathogen and improve patient outcomes.

Purpose: Carbapenem-resistant Acinetobacter baumannii (CRAB) is a high-priority antibiotic-resistant pathogen of public health concern and is associated with substantial morbidity and mortality. In 2024, the Infectious Disease Society of America (IDSA) recommended sulbactam-durlobactam in combination with a carbapenem as the preferred regimen for the treatment of CRAB. Despite IDSA recommendations, there isn’t a standard of care regimen for CRAB. Eravacycline, a synthetic fluorocycline, demonstrates structural resilience against common resistance mechanisms and shows in vitro activity against CRAB. This study aims to evaluate the clinical effectiveness of eravacycline-based therapy compared with best available therapy (BAT) in hospitalized patients with CRAB.
Methods: A retrospective chart review was performed on patients admitted to FMOL Health- Our Lady of the Lake with CRAB infections between January 2020 to December 2025. Patients aged 18 years and older with a documented infection of CRAB who receive one or more doses of eravacycline-based therapy or BAT were included. Patients were excluded if they were pregnant, did not receive antimicrobial treatment, discharged within 48 hours of admission, transferred to another hospital, or died prior to initiating antimicrobials. The primary outcome is a desirability of outcome ranking (DOOR) comparing eravacycline to BAT for treatment of infections caused by CRAB. The rankings are defined as the following: (1) clinical success without infectious complications or adverse events, (2) clinical success with infectious complications or adverse events, (3) absence of clinical success without infectious complications or adverse events, (4) absence of clinical success with infectious complications or adverse effects, and (5) death. Secondary outcomes include length of stay, duration of therapy, and relapse infection.
Results: A total of 271 patients were screened for eligibility. Of those evaluated, 96 patients were included in this study: 42 patients in the eravacycline group and 54 patients in the BAT group. The majority of patients were male (66.7%), black or African American race (51.04%), and had a median age of 60 years old. Most patients had at least one hospitalization in the 90 days prior to index hospitalization (65.6%) and had received IV antibiotics at least 90 days prior (60.4%). There was no significant difference between groups between any DOOR scale. The median length of hospital stay was 29.94 days, and the average length of therapy was 13.18 days. Repeat CRAB cultures were seen in 35.71% and 27.78% of patients in the eravacycline group and BAT group, respectively.
Conclusion: Among patients with CRAB, eravacycline did not appear to improve clinical outcomes or affect DOOR distribution.

Effect of Antibiotic Selection on Clinical Outcomes in Patients with Bloodstream Infections Caused by AmpC β-lactamase–producing Enterobacterales
Phuong Giao Nguyen Tran, Christopher M. Bland, Susan E. Smith, Caroline Turpin, Rachel Musgrove
St. Joseph's/Candler Health System

Background: Antibiotic resistance remains a major global health threat. Bacterial production of β-lactamases is a key resistance mechanism, with AmpC β-lactamases commonly identified in some Enterobacterales isolates. Mortality from bacteremia caused by AmpC-producing organisms has been reported to be significant. The 2024 Infectious Diseases Society of America (IDSA) guidance recommends cefepime or carbapenems for the treatment of infections caused by organisms at moderate risk of significant AmpC production and advises against ceftriaxone and piperacillin/tazobactam due to concerns about inducible resistance. However, clinical studies have not yet demonstrated superior outcomes with cefepime or carbapenems compared with ceftriaxone or piperacillin/tazobactam in this setting.

Methods: A multicenter, retrospective chart review was conducted during the period of January 2015 to December 2025. Eligible patients were adults 18 years of age or older and admitted to either St. Joseph’s Hospital or Candler Hospital with at least one blood culture isolating Hafnia alvei, Enterobacter cloacae, Citrobacter freundii, Klebsiella aerogenes, Yersinia enterocolitica, or Serratia marcescens. Patients were excluded if the initial antibiotic regimen was started at an outside hospital, if empiric therapy included a fluoroquinolone, or if blood cultures were polymicrobial. The primary objective was to determine if the use of IDSA-nonpreferred antibiotics (ceftriaxone, piperacillin/tazobactam) as empiric therapy in patients with bloodstream infections caused by AmpC β-lactamase–producing Enterobacterales results in increased incidents of suboptimal patient outcomes, as measured by greater rates of mortality, compared with IDSA-preferred agents (cefepime, meropenem). Secondary outcome measures include requirement of change of antibiotic therapy, total duration of antibiotic therapy, incidence of relapsed bacteremia, and incidence of Clostridium difficile infection while inpatient. All qualitative data points were evaluated using Chi-square analysis. All quantitative data points were evaluated using t-test analysis. A p-value of less than 0.05 was considered statistically significant.

Results: A total of 184 patients were screened and 146 of those patients were included in the analysis. The remaining 38 patients were excluded based on the criteria mentioned above, with the most common being polymicrobial blood cultures. The breakdown of the organisms isolated is as follows – 59 Enterobacter cloacae isolates (40%), 48 Serratia marcescens isolates (33%), 29 Klebsiella aerogenes isolates (20%), 9 Citrobacter freundii isolates (6%), and 1 Hafnia alvei isolate (1%). There was no statistically significant difference with regards to in-hospital mortality between the IDSA-nonpreferred antibiotics (ceftriaxone, piperacillin/tazobactam) and the IDSA-preferred agents (cefepime, meropenem) (p > 0.05). Secondary objectives were comparable between the two groups as well.

Conclusions: Use of IDSA-preferred agents, such as cefepime or meropenem, did not lead to improved clinical outcomes in patients with bacteremia caused by AmpC-producing organisms. However, this study has several important limitations. Notably, the study period spanned the COVID-19 pandemic, which may have introduced confounding factors affecting patient outcomes, including mortality. The true clinical significance must be assessed in larger, prospective, randomized control trials.

Background/Purpose: 
Hepatic encephalopathy (HE) is a common and burdensome complication of cirrhosis, associated with significant morbidity, mortality, and frequent hospitalizations. Lactulose remains the cornerstone of therapy; however, its use is often limited by poor tolerability and adherence. Rifaximin is recommended as add-on therapy for prevention of recurrence, but in clinical practice, it is increasingly used as monotherapy, particularly in patients who are unable to tolerate lactulose. 

Despite this shift, there is limited real-world data evaluating the effectiveness of rifaximin monotherapy in the inpatient setting. The purpose of this study was to compare clinical outcomes between patients treated with rifaximin monotherapy and those treated with rifaximin in combination with lactulose for the treatment of overt HE across the Wellstar Health System. 
 
Methodology: 
Adult patients (≥18 years) with cirrhosis who had been hospitalized for an episode of overt hepatic encephalopathy (HE; ICD-10 K76.82) between January 1, 2015, and July 31, 2025, were enrolled into this retrospective cohort study. These patients were categorized according to the treatment they received while hospitalized: those treated with rifaximin as monotherapy, and those treated with rifaximin + lactulose. Patients with acute liver failure, active infection, intensive care unit admissions, or hospitalizations of < 24 hours were excluded. The primary outcome was improvement in hepatic encephalopathy, defined as a reduction of one or more points in the West Haven Score grade during hospitalization. Secondary outcome measures include changes in serum ammonia levels, length of stay (LOS), acute kidney injury (AKI) events, in-hospital mortality, 30-day mortality, and 30-day readmissions due to HE. The continuous data collected were compared using two-sample t-tests. Categorical data collected were compared using chi-squared analyses. A p-value of ≤ .05 was used to determine if observed differences are statistically significant. 
 
Results: 
A total of 104 patients were included, with 52 patients in each group. Baseline characteristics were well balanced between groups, including age (57.3 vs 56.8 years, p=0.84), Charlson Comorbidity Index (4.94 vs 4.79, p=0.48), and MELD score (~20 in both groups, p=0.91). 

Both treatment groups demonstrated meaningful reduction in WHS grade during hospitalization. The mean WHS decreased from 2.94 to 0.96 in the lactulose + rifaximin group and from 2.87 to 0.88 in the rifaximin monotherapy group. The degree of improvement was similar between groups (mean change: 1.98 vs 1.99, p=0.96).  

Ammonia levels decreased in both groups as well, from 75.7 to 53.9 µmol/L in the lactulose + rifaximin group and from 71.3 to 52.3 µmol/L in the rifaximin group, with no significant difference observed (p=0.61). 

Hospital length of stay was numerically shorter in the rifaximin monotherapy group (5.38 vs 6.85 days), though this did not reach statistical significance (p=0.17). 

Rates of AKI, 30-day readmission, and mortality were low and comparable between groups. AKI occurred in 3.8% vs 5.8% of patients (p=0.65), and 30-day readmission occurred in 0% vs 3.8% (p=0.15) in the lactulose + rifaximin and rifaximin groups, respectively. In-hospital mortality occurred in 0% of patients in the lactulose + rifaximin group and 5.8% in the rifaximin group; however, this difference was not statistically significant (p=0.08). 

Conclusions: 
Rifaximin monotherapy demonstrated similar effectiveness to combination therapy with lactulose in reducing WHS grade and reducing ammonia levels during hospitalization. 

No meaningful differences were observed in readmissions, AKI, or overall safety outcomes. While not statistically significant, the shorter LOS observed in the monotherapy group may suggest a potential advantage that warrants further investigation. 

These findings support the idea that rifaximin monotherapy may be a reasonable alternative in select patients, particularly those who are unable to tolerate lactulose. Given the limitations of retrospective data and potential confounding factors, larger prospective studies are needed to better define the role of rifaximin monotherapy in the management of hepatic encephalopathy. 

IMPACT OF A PHARMACIST-DRIVEN PENICILLIN ALLERGY RE-LABELING PROCESS IN THE EMERGENCY DEPARTMENT SETTING
Erin Schuld PharmD, Aayush Patel PharmD, Mckenzie Hodges PharmD
Piedmont Columbus Regional Midtown-Columbus GA

Background/Purpose: Approximately 10% of U.S. patients report a penicillin allergy, yet fewer than 1% are truly allergic. Mislabeling often leads to use of broad-spectrum antibiotics, increasing antimicrobial resistance and risk of adverse effects. Pharmacist-driven allergy clarification protocols may improve antibiotic stewardship by enabling safe re-labeling of inaccurate allergy records. This study evaluates the impact of a pharmacist-driven penicillin allergy re-labeling protocol in the emergency department (ED) using the institution’s hypersensitivity pathway and the Pen-FAST risk stratification tool.

Methods: We conducted a single-center, retrospective chart review of adult patients (≥18 years) presenting to the ED between February 2, 2026 and March 31, 2026 with a documented penicillin allergy. Patients were excluded if they could not meaningfully participate in the allergy assessment for any reason.  The primary outcome was the proportion of patients safely and successfully re-labeled using the pharmacist-driven protocol. Secondary outcomes included changes in antibiotic therapy following re-labeling and incidence of adverse reactions during oral or test-dose challenges. Data were abstracted from electronic health records and analyzed using descriptive statistics.

Results: A total of 559 patients were included in this study. 441 patients were not able to have their allergies assessed by a pharmacist. 70 unassessed patients were on antibiotics and, of these, 29 patients potentially could have undergone a change to their antibiotic regimen. 118 patients were able to have their allergy assessed and re-labeled by a pharmacist. 46 assessed patients were receiving antibiotics. Of these 46, 18 patients underwent changes to their antibiotic regimen secondary to the pharmacist assessment. The most frequent change was from a fluoroquinolone, namely levofloxacin, to a cephalosporin with cefepime and ceftriaxone being the most common agents. The second most common change was from aztreonam to a cephalosporin with cefepime and ceftriaxone being the most common agent. 3 challenges (2 amoxicillin and 1 cephalosporin) were performed with no adverse reactions reported.
 
Conclusion: Implementation of a standardized Pen-FAST-based workflow enabled allergy clarification in a high-acuity setting by a clinical pharmacist. Some patients were able to be successfully transitioned to a first line recommended agent secondary to their allergy assessment, supporting the safety of a pharmacist-driven allergy assessment. While a majority of patients assessed by a pharmacist were not receiving antibiotics, full documentation of the allergy assessment in the electronic medical record may have downstream benefits should antibiotics be required during their next encounter. Overall, a pharmacist-driven penicillin allergy re-labeling process in the ED is feasible, safe, and clinically impactful.

Contact: [email protected]

Authors: Chase Arrington; Kelsey Bouwman; Dorothy Williams

Background: Urinary tract infections (UTIs) account for 30-32% of all healthcare-acquired infections, with Enterococcus species found in 15.9% of all catheter-associated UTIs. Standard treatment options include aminopenicillins, fosfomycin, nitrofurantoin, daptomycin, or vancomycin; however, resistance rates to these continue to climb. Linezolid offers an appealing alternative, but its ability to concentrate within the bladder could limit its clinical utility for UTIs. The manufacturer reports that approximately only 30% of the dose is excreted within the urine. Few retrospective studies exist looking at linezolid's effectiveness in UTIs, but the available data shows similar outcomes regarding clinical success. This study was conducted to assess linezolid’s effectiveness within lower UTIs caused by Enterococcus species in comparison to standard therapies.  

Methods: This is a single system, retrospective cohort study assessing linezolid's effectiveness in UTIs caused by Enterococcus species. The study included patients admitted between August 15, 2022, and August 15, 2025. Patients were included if they were 18 years or older, had a positive urine culture reporting an Enterococcus species, and it was their first encounter within the timeframe of this study. Patients were excluded if they had polymicrobial infections, negative urinalysis (<10 white blood cells per high-power field or leukocyte esterase negative), positive blood cultures, received fewer than three days of effective therapy, were pregnant or incarcerated, received both linezolid and another active antibiotic, or had been diagnosed with pyelonephritis. The primary outcome was a composite of bacterial persistence or antibiotic reinitiation within 14 days. Secondary outcomes included length of stay, 30-day recurrence or readmission related to UTI, development of resistance to linezolid, and mortality.  

Results: A total of 128 patients were included, with 37 receiving linezolid and 91 receiving conventional therapy. For the primary outcome of bacterial persistence or antibiotic reinitiation, no significant difference was found between linezolid and conventional therapy (13.51% vs. 9.89%, p=0.545).  No differences were observed between groups in the secondary outcomes of 30-day UTI readmission rate (24.32% vs. 15.38%, p=0.309), median length of stay (5.83 vs 6.76 days, p=0.592), or 30-day mortality (2.70% vs 8.79%, p=0.446). No patients developed resistance to linezolid within 30 days. Rates of thrombocytopenia during treatment were also comparable between groups (2.70% vs. 3.30%, p=1).  

Conclusion: In this retrospective cohort study, linezolid demonstrated comparable outcomes and safety to conventional therapies for the treatment of Enterococcus UTIs. This supports the potential utility of linezolid in UTIs despite concerns regarding urinary drug concentrations, particularly in cases involving resistant Enterococcus species. Larger randomized controlled studies are needed to confirm the findings seen within this study.  

Email: [email protected]

Title: Evaluation of Antibiotic Duration Between Concordant vs Discordant Multiplex Pneumonia PCR and Respiratory Culture Results 
Authors: Kala Eliacin, Rachel Tendler, Haodi Ruan  
Background/Purpose: Multiplex pneumonia PCR panels provide rapid identification of respiratory pathogens; however, discrepancies between PCR results and conventional respiratory cultures can introduce uncertainty in antimicrobial decision-making. The purpose of this study is to evaluate PCR-culture concordance vs discordance and their implications  on antibiotic duration in critically ill patients with suspected pneumonia.
Methodology: This was a single-center, retrospective chart review of adult patients admitted to the intensive care units at Emory Saint Joseph’s Hospital between January 1, 2023 and December 31, 2025 . Patients were included if they had suspected pneumonia and underwent both a multiplex pneumonia pathogen panel (PPP) and respiratory culture during the same hospitalization. Patients were excluded if they had a concurrent infection, died within 5 days of specimen collection, or had concordant negative PCR and culture results. The primary outcome was total duration of antibiotic therapy within 14 days of PPP and culture collection. Secondary outcomes included antibiotic regimens eligible for change, antibiotic regimens changed, ICU length of stay (LOS), hospital LOS, and pathogen identification. Continuous variables were reported using descriptive statistics and compared between groups using an unpaired t-test.
Results: A total of 70 patients were included, with 36 (51.4%) concordant results and 34 (48.6%) discordant results. Average age was around 62.3 years in the concordant group and 61.3 years in the discordant group and average weight was about 75 kg in both groups. Overall, the majority type of pneumonia identified in patients for both groups was community acquired pneumonia (CAP) with 41.7% in the concordant group and 47.1% in the discordant group. The mean total days of antimicrobial therapy within 14 days of index testing were 7.8 days in the concordant group compared with 8.0 days in the discordant group (p = 0.8303). ICU LOS was 13.8 days in the concordant group versus 13.2 days in the discordant group. Hospital LOS for the concordant and discordant group was 26.4 days versus 18.5 days, respectively. Antibiotic regimens were eligible for modification in 48 patients (68.6%), including 23 (63.9%) in the concordant group and 25 (73.5%) in the discordant group. Antibiotic regimens were changed in 37 patients (52.9%) overall following PPP results. Multiplex PCR detected more pathogens than respiratory culture, with common organisms including Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Overall, resistance genes were detected in 9.7% of cases with mecA/C being the most common in both the concordant group (13.5%) and discordant group (25.7%).
Conclusions: There was no difference in antibiotic duration of treatment or ICU LOS between concordant and discordant PPP and respiratory culture results. Hospital LOS, however, was shorter in the discordant group but may have been due to confounding factors. PPP results frequently identified opportunities for antimicrobial optimization, and antibiotic regimens were modified in over half of patients. These findings show that concordance vs discordance between multiplex PCR and culture results were not associated with a difference in antibiotic duration in critically ill patients with suspected pneumonia.

Title: Tracking the Trends: Staphylococcus aureus Bacteremia Rates in a Rural, Not-for-Profit Hospital 
Authors: Natalie Ly, Heather Gibson, Allison Cid, Gretchen Arnoczy 
FirstHealth Moore Regional Hospital – Pinehurst, NC 
 
Background: Infectious Diseases (ID) consultation is associated with improved outcomes in Staphylococcus aureus bacteremia (SAB), yet access may be limited in community settings. This study evaluated SAB outcomes following interventions to increase ID consultation at a community health system. Interventions included increased ID availability for telemedicine consults, as well as a recommendation for ID consultation for all appropriate SAB cases. 

Methods: This retrospective chart review study utilized electronic medical records from FirstHealth patients with data collected from January 1, 2024 through January 31, 2025. All patients within the 4-hospital FirstHealth of the Carolinas system who had blood cultures positive for Staphylococcus aureus were evaluated. Patients were excluded if they met the following criteria: died or transitioned to comfort care within 3 days of positive blood culture, transferred to another institution, or were lost to follow-up. Patient characteristics and demographics were collected including age, sex, methicillin-resistant Staphylococcus aureus (MRSA), persistent bacteremia, persons who inject drugs (PWID), confirmed endocarditis, transthoracic echocardiogram (TTE), transesophageal echocardiogram (TEE), and ID consult status, as these are predictors of 6-month mortality for patients with SAB. The primary outcome studied was difference in 6-month mortality and recurrence rates, compared to rates observed within the hospital system during the COVID-19 pandemic. Secondary outcomes include differences in mortality or frequency of ID consults, particularly related to the implementation of ID telemedicine consults, as well as use of dalbavancin or oritavancin. 

Results: A total of 147 patients were included in this study. The 6-month mortality rate was 40/147 (27.2%), which was 5.9% lower than during the previous studied time frame; however, this was not statistically significant with a p-value of 0.25 (Relative Risk 0.82 [95% Confidence Interval 0.58-1.15]). Recurrence was defined as a return of SAB at least 2 weeks after resolution of the initial episode, as evidenced by documented negative blood cultures and improvement of clinical symptoms. The 6-month recurrence rate was 10/147 (6.8%), which was 2.5% lower than during the previous studied time frame. This was also a nonsignificant finding (Relative Risk 0.73 [95% Confidence Interval 0.34-1.56], p-value 0.42). The majority of patients 140/147 (95.2%) had an ID consult, as compared to 116/172 (67.4%) in the previous study. This 27.8% increase was statistically significant at a p-value of <0.001, with the rise in consult rates primary driven by telemedicine visits. There was also a higher incidence of cardiac imaging obtained and a trend toward shorter time to ID consult placed after positive blood culture. Utilization of long-acting lipoglycopeptides was low, as only 3 patients received dalbavancin and none received oritavancin.  
There are a number of factors that may have impacted the results of this study. Firstly, there were a small number of patients evaluated, which could make it more difficult to detect statistical significance when the study is not adequately powered. Furthermore, the population in this study included non-COVID patients, in contrast to the previous studied time period where patients had COVID-19 complicating their SAB. These patients may have differed in baseline illness severity, potentially biasing outcome comparisons.  

Conclusions: In this study, the expansion of ID access was associated with significantly higher ID consultation rates and favorable trends in 6-month mortality and recurrence rates among patients with SAB. These findings support the role of expanded ID access in improving SAB management within community health systems.

Title: Antimicrobial Prescribing Practices for Community-Acquired Pneumonia (CAP) in a Community, Teaching Health System
Authors: Anna Collins, Chris Whitman, Rachel L. Foster, Jeff Bruni, Cherie Abernathy
Background: Community-acquired pneumonia (CAP) is a major U.S. health concern, particularly in adults aged 65 years and older. Many antibiotic prescriptions may deviate from guidelines, with frequent overuse of broad-spectrum antibiotics, failure to de-escalate therapy, and prolonged durations of therapy. This project aims to evaluate prescribing patterns for the treatment of community-acquired pneumonia (CAP) within Infirmary Health (IH). Antibiotic selection and treatment durations were compared to current national guideline recommendations to determine guideline concordance and appropriateness of current inpatient CAP treatment within IH. These findings will support data-driven antimicrobial stewardship efforts by identifying specific areas for improvement in prescribing practices to enhance patient care and reduce antimicrobial resistance within the community.
Methods: This study is a retrospective chart review of adult inpatients who were diagnosed with and treated for CAP within IH in 2024. International Classification of Diseases (ICD-10) codes and Diagnosis Related Groups for CAP were used to obtain patients. Patients were then randomized and 270 patients were reviewed. The first admission in 2024 was included per patient. The primary outcome was to determine the prevalence of Infectious Diseases Society of America (IDSA)/American Thoracic Society (ATS) guideline-concordant CAP treatment according to disease severity and risk factors. The primary outcome was assessed at three different timepoints: day one of CAP therapy, day two of CAP therapy, and the last day of inpatient CAP therapy. Secondary outcomes included comparing baseline characteristics, length of stay, 30-day readmission, and 30-day all-cause mortality between patients treated according to IDSA/ATS guidelines and those that were not. Patients were excluded if they received less than 72 hours of antibiotics for CAP treatment, had a concurrent infection requiring a longer length of therapy or alternative drug selection, any hospital-acquired or ventilator-associated pneumonia, had a diagnosis of cystic fibrosis or other advanced structural lung disease, had conditions predisposing to noncommunity-acquired pathogens, patients who left against medical advice, expired, or transitioned to hospice during the CAP treatment course, history of lung transplant, pregnant or breastfeeding, incarcerated, those transferring from an outside hospital, and patients with a pneumonia-related complication.
Results: There were 2,576 unique patients identified. Of these, 270 charts were reviewed and 130 patients were included in the final analysis. The median age was 71 and 68 years in the guideline concordant and discordant groups, respectively, and baseline characteristics were similar between the two groups. Recent healthcare exposure in the prior 90 days was more common among patients receiving guideline-discordant therapy: 19% had received intravenous (IV) antibiotics compared with 2% in the guideline-concordant group, and 29% had a hospital admission compared with 9%, respectively. Overall, 64% of patients received guideline discordant therapy. Rates of guideline discordance were similar across the three timepoints assessed. Notably, 36% of patients received empiric MRSA or Pseudomonas therapy when it was not indicated. The antibiotic lengths of therapy were 8 and 9 days in the guideline concordant and discordant groups, respectively. There were no significant differences in length of stay, 30-day readmission, or 30-day mortality between the two groups.
Conclusions: The majority of patients in this population received guideline discordant therapy for the treatment of CAP, with trends toward overly broad antibiotic selection and longer than recommended durations of therapy. Patients receiving guideline discordant therapy were more likely to have an admission and receipt of IV antibiotics in the prior 90 days. These findings highlight an opportunity to optimize antibiotic selection and duration of therapy for CAP treatment within Infirmary Health.

Title:
Treatment of Staphylococcus Aureus Bacteremia and the Impact of Infectious Disease Consultation

Authors:
Westley Eccles, Stephen Eure, Doug Carroll

Practice Site:
DCH Regional Medical Center-Tuscloosa, AL

Background: Staphylococcus aureus (S. aureus) remains a highly virulent pathogen causing infections worldwide. The pathogen frequently invades into the bloodstream to cause S. aureus bacteremia, which currently has an in-hospital mortality range of 10% to 30%. The Infectious Diseases Society of America (IDSA) guidelines on methicillin-resistant S. aureus (MRSA) remain an important backbone on proper management of S. aureus bacteremia. The IDSA guidelines outline antibiotic selection, classification, and duration of therapy, as well as recommended additional tests to manage the infection. These guidelines are still commonly followed to this date, with some notable differences in current best practice. It is highly important that patients receive optimal antibiotics and proper duration of antibiotic treatment to improve outcomes and reduce mortality. Other research projects have been conducted to compare patient outcomes when an infectious diseases (ID) specialist is directly involved in the management of S. aureus bacteremia. These studies suggest an improvement in both guideline-adherent management of the infection and a reduction in patient mortality. This project aims to assess the overall performance in managing S. aureus bacteremia in our facility, with a comparison between two groups (ID consultation versus no ID consultation).

Methodology: This study was a retrospective chart review of patients ≥18 years of age with positive blood cultures for either methicillin-sensitive S. aureus (MSSA) or MRSA between January 2024 to June 2025. A total of 140 patients were identified within our time period and screened for inclusion. After a chart review to confirm eligibility, 99 patients were included in the project. These patients were divided based on presence of ID consultation, where 42 patients received an ID consult and 57 patients did not receive an ID consult. Individual elements of performance (i.e., antibiotic selection, repeat blood cultures, echocardiography, and duration of therapy) were created to assess patient care based on the standard set by current practice and guidelines. Outcomes were compared between patients who had ID specialist consultation to those without ID specialist consultation. The primary outcome was a composite of all elements of performance, where compliance with all elements of performance was required to meet the primary outcome. Additional secondary outcomes included each individual element of performance, inpatient mortality, average duration of therapy, and hospital readmissions within 30 days, due to infectious process.

Results: Thirty-two (76%) patients with ID consult met the primary outcome compared to twenty-two (39%) patients without ID consult. Secondary outcomes included each individual element of performance alone. For ID consult, each individual element of performance was met as follows: thirty-five (83%) patients for antibiotic selection; Forty-one (98%) for repeat blood cultures; Forty-one (98%) for echocardiography; thirty-eight (91%) for guideline-compliant therapy. For no ID consultation, each individual element of performance was met as follows: forty-two (74%) patients for antibiotic selection; forty-nine (86%) for repeat blood cultures; Forty-four (77%) for echocardiography; thirty-four (60%) for guideline-compliant therapy. Ultimately, there was greater adherence to all elements of performance in the group of patients that had an ID specialist onboard in their care.

Conclusions: Adherence to current guidelines and best practice was more commonly seen in patients with an ID specialist onboard. Overall, ID specialist involvement improved the appropriate management of patients diagnosed with S. aureus bacteremia.

A RETROSPECTIVE EVALUATION OF THE IMPACT OF VANCOMYCIN AUC DOSING ON ACUTE KIDNEY INJURY AND DRUG EXPOSURE IN HOSPITALIZED PATIENTS.
Shemaiah Caine, Deanne Tabb, Tushar Patel, Aayush Patel Piedmont Columbus Regional Midtown Columbus, GA


Background/Purpose: Vancomycin trough-based monitoring is associated with excessive exposure and increased acute kidney injury (AKI). however, trough-based monitoring is associated with excessive drug exposure and increased risk of acute kidney injury (AKI). ASHP/IDSA consensus guidelines recommend AUC guided dosing with a target AUC of 400 - 600 mg·hr/L to improve safety and efficacy. In January 2025, Piedmont Columbus Regional Midtown implemented InsightRX®, a Bayesian dosing platform designed to support individualized AUC guided vancomycin dosing. The purpose of this study is to assess the impact of this transition on AKI incidence and drug exposure.




Methodology: This retrospective single center pre/post cohort study will include adult patients who received ≥ 72 hours of intravenous vancomycin, comparing a trough-based cohort (Oct-Dec 2024) with an AUC guided cohort after InsightRX® implementation (Jun-Aug 2025). Data from Epic and InsightRX® will capture demographics, baseline renal function, vancomycin dosing characteristics, and nephrotoxin exposure. The primary outcome is AKI during therapy or within 48 hours after the last dose, defined per KDIGO criteria. Secondary outcomes include time to target AUC, number of levels drawn, trough distributions, and total vancomycin exposure. Continuous variables will be analysed using a two-sample t-test, and categorical variables using Fisher’s exact test.




Results:  For the primary outcome, AKI occurred in approximately 9% of patients in the trough-based group compared with 7% in the AUC-guided group. The p-value of 1.00 suggests there was no statistically significant difference between groups. However, given the small sample size and descriptive design, this analysis was likely underpowered to detect meaningful differences in AKI risk. For secondary outcomes, average vancomycin exposure within the first 72 hours was similar between groups, at approximately 2,300 mg/day in the trough-based cohort and 2,208 mg/day in the AUC-guided cohort, with no statistically significant difference observed, p=0.64. However, a greater proportion of patients in the AUC-guided group achieved target therapeutic exposure within 48 hours compared with the trough-based group, 56% versus 18%, respectively, which was statistically significant with a p-value of 0.005. Within the trough-based cohort, most patients, 68%, had trough concentrations between 11 and 14.9 mcg/mL, while 27% were between 15 and 20 mcg/mL. Only one patient had a trough concentration greater than 20 mcg/mL.


Conclusions: AUC guided vancomycin dosing was associated with a significantly higher rate of early target attainment within 48 hours compared to trough-based dosing. Despite this difference, overall vancomycin exposure within the first 72 hours of therapy was similar between groups, suggesting comparable initial dosing intensity. There was no statistically significant difference in the incidence of acute kidney injury between the two strategies; however, this study was likely underpowered to detect meaningful differences in safety outcomes. Overall, these findings suggest that AUC guided dosing may improve early pharmacokinetic target achievement without increasing nephrotoxicity, though larger studies are needed to further evaluate its impact on renal outcomes.




[email protected]

Comparison of cefazolin plus ertapenem to alternative approaches in patients with persistent MSSA bacteremia while on cefazolin
Natalie Harris, PharmD1; Caroline Jozefczyk, PharmD, BCIDP2; Jake Crocker, PharmD, BCIDP2; Sarah Al Mansi, MD1; Brandon Bookstaver, PharmD, BCIDP1,3

• Prisma Health Richland Hospital, Columbia, SC
• Prisma Health Greenville Memorial Hospital, Greenville, SC
• University of South Carolina College of Pharmacy, Columbia, SC

Background: Persistent methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia despite standard cefazolin therapy poses a significant clinical challenge. Historically, salvage approaches have involved anti-staphylococcal penicillins (ASPs), given the growing concern for cefazolin inoculum effect. With ASPs less favorable pharmacokinetic and safety profile, various combination regimens have emerged as potential alternatives. Data directly comparing salvage strategies remains limited. This study compared outcomes of cefazolin plus ertapenem versus alternative salvage therapies in persistent MSSA bacteremia.
Methods: This retrospective cohort study included adults who failed cefazolin and received salvage therapy for persistent MSSA bacteremia from March 1, 2021 to August 31, 2025. Patients were excluded if they transferred from another hospital, had polymicrobial bacteremia, died within 24 hours, or received empiric therapy for > 24 hours after positive blood cultures. The primary objective was to compare the duration of MSSA bacteremia after salvage therapy in patients receiving cefazolin plus ertapenem versus alternative salvage strategies. Secondary objectives included all-cause mortality, infection related re-admission, and adverse effects (ADEs) in both groups.
Results: Fifty-seven patients were included, with 30 in the cefazolin plus ertapenem cohort and 27 in the alternative cohort. The most common source was skin and soft tissue (n=19, 33.3%), and endocarditis was the most common complication (n=17, 29.8%). Most patients in the alternative salvage cohort received nafcillin (n/N=19/30, 70.4%). The average duration of bacteremia after salvage was 1.6 and 2.8 days in the cefazolin plus ertapenem and alternative cohorts, respectively. Patients receiving cefazolin plus ertapenem experienced higher rates of 90-day mortality (23.3% vs 22.2%) and infection-related re-admission (26.7% vs 11.1%), however, patients receiving alternative salvage therapy experienced more ADEs (51.9% vs 36.7%).
Conclusion: Cefazolin plus ertapenem shortened bacteremia duration and led to less ADEs compared with alternative regimens, supporting the use of this combination as a salvage therapy option in persistent MSSA bacteremia.

Title: 
Safety Outcomes of Empiric Linezolid versus Vancomycin in Patients with Pneumonia and Risk Factors for Methicillin-Resistant Staphylococcus aureus Infection

Purpose:
Vancomycin and linezolid are primary agents recommended for treating methicillin resistant Staphylococcus aureus pneumonia¹. However, linezolid tends to become the secondary agent during therapy selection due to lack of familiarity, cost, or concern for adverse effects of myelosuppression or serotonin syndrome. The purpose of this study is to investigate key safety outcomes in use of intravenous linezolid and vancomycin for the purpose of inpatient treatment of pneumonia.

Methods:
The study was conducted as a single-center, Institutional Review Board (IRB)-approved, retrospective observational cohort study. Patients were identified from clinical data already available in the Ascension central data repository (across 11 practice sites) and screened based on inclusion and exclusion criteria. Encounters were then categorized by receipt of either “vancomycin” or “linezolid,” with further stratification for the various primary and secondary outcomes. The primary outcome is defined as composite safety outcomes, defined as incidences of acute kidney injury, cytopenias, serotonin syndrome, infusion reactions, and suspected or confirmed Clostridioides difficile infection. This data was collected from the facilities’ respective electronic health records for patients admitted between January 1, 2020 to September 30, 2025. Data was analyzed using Student’s t-test or Wilcoxon rank sum test or Chi-square or Fisher’s exact test, as appropriate for the data type. Alpha was set as 0.05 with 80% power.

Results:
14 patients were included in the study from a single site of the 11 sites. The remaining sites are assessed in a separate analysis. 7 patients were in each of the two groups, vancomycin and linezolid. Baseline characteristics were similar between groups. There was no significant difference found between the composite safety outcomes in either treatment group. Within the secondary outcomes, vancomycin patients had a statistically significant increased rate of 30-day all-cause mortality when compared to those of the linezolid group.

Discussion:
In this study, we found no significant difference in composite safety outcomes between patients with pneumonia being treated with vancomycin or linezolid. This may represent comparable safety profiles between the agents. It is important to consider the increase in 30-day all-cause mortality rate and apply it to a patient’s full clinical picture. More research is warranted with a larger sample size.

Authors’ Names: Madison Moncus, Ashton Dickinson, Mary Massaro, Brandon Hawkins, Alexandra McBrayer, Clark Cutrer, Samantha Walker 

Background: Febrile neutropenia is a life-threatening complication in patients with malignancy and hematopoietic stem cell transplant (HSCT) recipients. Empiric anti-pseudomonal beta-lactam therapy is recommended; however, the optimal strategy for narrowing therapy based on culture data remains uncertain.  While de‑escalation to pathogen‑directed regimens is widely endorsed when microbiologic data is available, the evidence supporting this practice remains limited. Emerging data suggests de-escalation may safely reduce broad-spectrum antibiotic exposure; though evidence in high-risk populations, such as those with hematologic malignancy and HSCT recipients, is limited. This study evaluates the safety and efficacy of narrowing empiric therapy to pathogen-directed therapy in adults with malignancy and HSCT recipients. 

Methods: This retrospective cohort evaluates adult hospitalized patients with cancer-associated febrile neutropenia between January 2020 and January 2025. Eligible patients received initial empiric antipseudomonal beta-lactam therapy and had a positive bacterial culture obtained within 72 hours of fever onset. Patients with pseudomonal infections, organisms resistant to definitive therapy, ANC recovery (ANC > 500 cells/mm³) within 72 hours of initiating antibiotic therapy, or death within 72 hours were excluded. Patients were stratified into two groups: those who remained on empiric anti-pseudomonal therapy for more than 72 hours after susceptibility results became available, and those who were narrowed to pathogen-directed therapy within 72 hours. Data was collected securely via RedCap. The primary composite outcome included escalation of antibiotic therapy or infection recurrence within 30 days. Secondary outcomes included incidence of new onset Clostridioides difficile infection (CDI), hospital length of stay, all-cause mortality at 30 days, new positive culture with resistance demonstrated to initial treatment agents within 30 days, and time to de-escalation. Data collected included baseline demographics, cancer type, culture results, antibiotic regimens, fluoroquinolone prophylaxis, resistance patterns, and readmissions. Categorical variables were analyzed using chi-square or Fisher’s exact test, and continuous variables were analyzed using the Mann-Whitney U test. Data was analyzed utilizing SPSS. 

Results: A total of 44 patients met inclusion criteria, with 32 patients in the empiric therapy group and 12 patients in the pathogen‑directed therapy group. Baseline demographics, malignancies, and microbiologic characteristics were similar between groups, with most patients having hematologic malignancies and comparable distributions of gram‑positive and gram‑negative organisms. Patients de‑escalated to pathogen‑directed therapy received significantly shorter durations of antipseudomonal therapy (median 3 vs. 18 days, p < 0.001). De‑escalation typically occurred within 24 hours of susceptibility reporting (58%). The composite primary endpoint occurred in 72% of the empiric group and 42% of the pathogen‑directed group (p = 0.085). Antibiotic escalation was more frequent among patients who remained on empiric therapy (50% vs. 8%, p = 0.015), with meropenem accounting for most escalations (94%, p = 0.003). Rates of recurrent fever, repeat positive cultures, readmission due to infection, CDI, and 30‑day mortality were low and did not differ significantly between groups. Hospital length of stay was shorter in the pathogen‑directed group (7 vs. 20 days, p = 0.005). 

Conclusions: De‑escalation of empiric antipseudomonal therapy to pathogen‑directed therapy was associated with substantially reduced broad‑spectrum antibiotic exposure and shorter hospital length of stay without increased treatment failure, recurrent infection, or mortality. These findings support the safety of culture‑guided de‑escalation in adults with malignancy‑associated febrile neutropenia, including HSCT recipients, and highlight the need for larger multicenter studies to confirm generalizability across diverse oncology populations. 

Authors: Shannon R. Mayberry, Cristina Martinez, Benjamin Albrecht, Sujit Suchindran, Sarah B. Green  

Resident e-mail for contact: [email protected] 


Purpose/Background: 
Treatment of low-risk AmpC-inducible organisms should rely on antimicrobial susceptibility testing (AST) to guide treatment of infection. Current Infectious Diseases Society of America (IDSA) guidelines identify Serratia marcesens, Morganella morganii, and Providencia spp. as low-risk species. Per this guidance, when susceptibility to agents such as ceftriaxone and piperacillin-tazobactam is demonstrated, treatment with that antibiotic is considered appropriate. However, infections with high bacterial burden, including endocarditis and central nervous system (CNS) infections, pose an additional challenge for optimal treatment selection. The IDSA guidelines state cefepime may be reasonable to utilize for high-inoculum infections despite susceptibility to ceftriaxone, due to less risk of AmpC hydrolysis. However, efficacy to cefepime in this setting is uncertain given potential for an inoculum effect, while carbapenems appear less affected. Clinical evidence remains limited, and treatment guidance for high-inoculum AmpC infections is unclear. In this retrospective case series, we describe the clinical outcomes of patients treated with a carbapenem, cefepime, or an alternative beta-lactam agent for deep-seated endovascular and CNS infections due to low-risk AmpC-inducible organisms.  

Methods: 

This IRB approved, retrospective case series included adults (≥18 years) admitted to Emory Healthcare acute care hospitals between January 1, 2023, and January 31, 2025, with endocarditis, endovascular, or CNS infection due to a low-risk AmpC-inducible organism (Serratia marcescens, Morganella morganii, or Providencia spp.). Patients were identified through diagnosis codes (e.g. endocarditis, endovascular infection, CNS infection) and a positive blood or CNS culture for a low-risk AmpC organism. A total of 28 patients were identified for review. Further exclusion criteria were polymicrobial cultures, switch of therapy after 72 hours, or definitive non–β-lactam or combination therapy. Of this, 10 patients were included for final evaluation.  Case data collected included patient demographics, comorbidities, infection characteristics, microbiology, antimicrobial therapy, 30-day all-cause mortality, 90-day infection recurrence, 90-day readmission, and adverse events. 

Results: 

Ten patients with high-inoculum infections due to low-risk, high inoculum AmpC-inducible organisms were included. Nine infections were caused by Serratia marcescens and one by Morganella morganii. Infection types included endovascular infections (n=6), central nervous system infections (n=3), and infective endocarditis (n=1). Initial antimicrobial regimens varied and included ceftriaxone, cefepime, ceftazidime, and piperacillin/tazobactam, with several patients undergoing antibiotic escalation after organism identification. All but one patient had infectious diseases consultation. Antibiotic modifications were common, ranging from zero to eight changes during admission. One patient experienced inpatient mortality. A single patient had a 90-day infection-related readmission. No consistent signal of clinical failure was observed among patients treated with ceftriaxone compared with cefepime or carbapenems. Despite frequent antimicrobial adjustments, most patients achieved clinical stability without recurrent infection or excess mortality within 90 days. 

Conclusions:  

In this small retrospective case series, clinical outcomes were similar among patients receiving ceftriaxone, cefepime, or carbapenems for high-inoculum infections caused by low-risk AmpC-inducible organisms. Rates of inpatient mortality and 90-day readmission were low, and no clear outcome advantage was observed with broader-spectrum therapy. These findings suggest that carefully selected non-carbapenem β-lactams may be a reasonable option in certain deep-seated infections when supported by susceptibility data and close clinical monitoring. However, frequent antibiotic escalation highlights ongoing clinician concern regarding inducible resistance and the inoculum effect. Given the limited sample size and descriptive design, definitive comparative conclusions cannot be drawn. Larger, multicenter studies are needed to better define optimal therapy in this high-risk population. Until additional data are available, antimicrobial stewardship decisions should balance theoretical resistance risks with the goal of preserving carbapenem activity. 

Multidrug resistant organisms can be difficult to treat due to limited options and are a public health threat. Increasing rates of antimicrobial resistance have led to high rates of mortality and greater costs for the healthcare system. Isolates are labeled as carbapenem-resistant Enterobacteriaceae (CRE) if noted to have resistance to at least one carbapenem agent or produce a carbapenemase. There are multiple mechanisms of carbapenem resistance including carbapenemase production, porin channel mutations, and overexpression of efflux pumps. The literature suggests that the risk of carbapenemase production is less than 3% in isolates that are resistant to ertapenem but susceptible to meropenem and imipenem-cilastatin. A study by Wang et al showed that ertapenem-mono-resistant isolates were more likely to be susceptible or intermediate to beta-lactams and beta-lactam/beta-lactamase inhibitor combination agents when compared to meropenem and imipenem-cilastatin resistant isolates. However, current Infectious Diseases Society of America (IDSA) guidelines recommend that they be treated with extended infusion of meropenem or imipenem-cilastatin.  
The Clinical and Laboratory Standards Institute (CLSI) recently lowered the susceptibility breakpoint of ertapenem from a mean inhibitory concentration (MIC) of <2 to <0.5 µg/mL, increasing the number of isolates that would be labeled as CRE. The purpose of this study was to describe the outcomes in patients with ertapenem mono-resistant Enterobacteriaceae infections, and to compare the use of carbapenem and non-carbapenem antibiotics in ertapenem mono-resistant isolates.  
This study was a single-center, retrospective chart review of mono-resistant Enterobacterales isolates from January 1st, 2023 to December 31st, 2024. Mono-resistance is defined as having an ertapenem MIC of > 1 mg/L and meropenem MIC of < 1 mg/L. Patients were included if they were > 18 years old at time of culture collection, were inpatient, and completed an antibiotic course for an infection with a positive culture. At our institution, genotyping data was only available for some blood cultures. Patients were excluded from analysis if cultures were collected at an outside facility, belonged to protected population, and did not receive antibiotic treatment. The comparative groups were patients treated with carbapenems, non-carbapenem beta-lactams, and non-beta-lactam antibiotics. The primary outcome was clinical cure of infection. To strengthen our analysis of the primary outcome, an infectious diseases physician validated the primary outcome. Secondary outcomes included microbiological cure, in-house mortality, and inpatient length of stay. For statistical analysis, chi-square tests and student t-tests were conducted when appropriate.  
Ninety-eight isolates were reviewed: 25 (26%) were treated with a carbapenem, 51 (52%) were treated with a non-carbapenem beta-lactam, and 22 (22%) were treated with a non-beta-lactam. Most isolates came from a respiratory (34%) or urinary (20%) sample. Clinical cure rates were similar across three groups, 76% vs 80% vs 77%, respectively (p=0.8955). A multivariable regression analysis adjusted for sex, age, bed-type, polymicrobial culture status, and specimen type revealed no difference in clinical cure between antibiotic groups. When comparing carbapenem and non-carbapenem treated patients, the portion of patients who died was significantly smaller in the non-carbapenem group, (7 patients [28%] vs 4 patients [6%], p=0.006). Length of stay was longer in the carbapenem group when compared to the non-carbapenem group, but this difference was not statistically significant (76 days vs 32 days, p=0.184).  
Similar rates of clinical cure were observed in the three different groups (carbapenem, non-carbapenem beta-lactam, and non-beta lactam antibiotics), despite the current IDSA recommendation to use extended-infusion carbapenems for these mono-resistant isolates. Longer rates of length of stay in the carbapenem-treated group may cause a significant burden on our healthcare system. This suggests that most mono-resistant isolates are not carbapenemase producing and could be treated with beta-lactam therapy, if reported as susceptible.  

Nguyen Minh Anh Ngo, Amanda Sowder
AdventHealth Orlando
Background: Cardiac implantable electronic devices (CIED) are essential for managing arrythmias and preventing sudden cardiac death thereby improving survival. However, transvenous CIED-related infections are a serious complication, occurring in 2% to 4% of high-risk patients yearly. Device-related infections are associated with increased healthcare costs, morbidity, and mortality. The 2023 American Heart Association Update on CIED Infections recommends cefazolin as a standard preprocedural systemic antibiotic, with vancomycin reserved for select patients, and suggest consideration of an antimicrobial envelope in high-risk patients. The use of a novel absorbable antibiotic envelope, coated with rifampin and minocycline eluted to local tissues over nine weeks, has been shown to reduce infection rates in CIED patients compared to standard care; however, data in high-risk populations remain limited. While the BLISTER study validated the use of a risk stratification tool to identify patients most likely to benefit from the antibiotic envelope with a qualifying score threshold over five, the comparison group used in this study received antibiotics that do not align with current recommendations. Currently, practical use of prophylactic antibiotic regimens varies at physicians’ discretion despite existing guidance. This study aims to describe outcomes of antibiotic envelope use compared to real-world antibiotic prophylaxis regimens in high-risk patients undergoing CIED placement.


Methods: Adult patients undergoing transvenous CIED placement, including first placement, generator exchange, or upgrade, at AdventHealth Orlando between October 1, 2024 and September 30, 2025 were identified using electronic health records report generation. Key exclusion criteria included epicardial pacing lead placement, leadless pacemaker, subcutaneous implantable cardioverter-defibrillators, or temporary pacing systems. High-risk patients were identified using the BLISTER score. The primary outcome was incidence of CIED-related infections at 12 months. Secondary outcomes included incidence of pocket hematoma, infection-related hospitalization, and all-cause mortality at 12 months.


Results: During the interim timeframe (October 1, 2024 – December 26, 2024), 265 patients were screened; 50 high-risk patients were identified based on BLISTER score of 6 or greater. Of these, 24 received the antibiotic envelope and 26 received other antibiotic prophylaxis. Baseline characteristics were well-balanced between groups, with a mean age of 70 years, 70% male, and 60% with history of severe left ventricle dysfunction. The majority of patients underwent cardiac resynchronization therapy-related procedure (86% new implant or generator exchange), followed by pacemakers (8%) and implantable cardioverter-defibrillators (6%). Regarding procedure type, 44% had generator exchanges and median procedure duration was 74 minutes (IQR 42 – 112 minutes). Antibiotic appropriateness, based on institutional standards, was 92% in the envelope group and 85% in the other antibiotics group. CIED-related infection at 12 months for the antibiotic envelope versus other antibiotics group was comparable between groups (4.1% vs 3.8%). Secondary outcomes resulted as follows: pocket hematoma (8.3% vs 3.8%), infection-related hospitalization (8.3% vs 15.3%), and all-cause mortality (20.8% vs 15.3%).


Conclusion: In this interim analysis, CIED-related infection rates were similar between patients receiving antibiotic envelope and those receiving other antibiotic prophylaxis regimens. While infection-related hospitalization showed higher rates in the other antibiotics group, these cases were driven by infectious sources outside of CIED. Additionally, the high all-cause mortality across both groups reflects the baseline risk of this patient population. These preliminary findings highlight the potential for cost savings  supporting  a default strategy of prophylactic antibiotics over antibiotic envelope. Moreover, standardized use of pre-procedural risk stratification tool prior to CIED procedures may allow for individualized approaches. Larger prospective studies are warranted to further define the role of antibiotic envelope use compared to real-world antibiotic strategies in high-risk patients.

Title: Identification of risk factors for beta-lactam resistant Pseudomonas aeruginosa bacteremia   

Background: Pseudomonas aeruginosa bloodstream infections (BSI) are associated with significant morbidity and mortality. Increasing resistance to antipseudomonal beta-lactams, including piperacillin-tazobactam, cefepime, and carbapenems, has complicated empiric treatment strategies.  Currently, institutional risk factors for beta-lactam resistant P. aeruginosa are largely derived from studies of respiratory isolates, which may not accurately reflect resistance patterns or risk factors in bloodstream infections. The goal of this study is to evaluate risk factors for beta-lactam resistant Pseudomonas aeruginosa bacteremia. 

Methods: This retrospective cohort study included patients 18 years and older within the Prisma Health system with a positive blood culture for P. aeruginosa from March 1, 2021 to August 31, 2025. The first positive blood culture within a 12-month period was included. Patients were excluded if they had cystic fibrosis. The primary objective of this study was to identify patient-specific risk factors for beta-lactam resistant P. aeruginosa BSIs (defined as resistance to cefepime or piperacillin-tazobactam). The secondary objectives were to identify risk factors for carbapenem-resistant P. aeruginosa bacteremia, determine predictors for isolates with elevated minimum inhibitory concentrations (MICs), and evaluate susceptibility patterns to novel antibiotics. Multivariate logistic regression was performed to determine independent predictors of beta-lactam and carbapenem resistance, as well as factors associated with isolates exhibiting elevated MICs. 

Research & Conclusion: In progress 

Title: Evaluation of Pediatric Pharmacy Driven Methicillin Resistant 
Staphylococcus Aureus (MRSA) Nasal Polymerase Chain Reaction (PCR) protocol 
Authors: Beth Addington, PharmD, BCPPS, Sarah Withers, PharmD, MS, BCIDP, Rachel Samples, PharmD, MBA 
Objective: To evaluate the impact of a pediatric pharmacy-driven MRSA nasal PCR protocol on the duration of anti-MRSA antibiotic therapy in pediatric patients before and after protocol implementation.
Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of pediatric infections. Current Infectious Diseases Society of America guidelines recommend MRSA nasal polymerase chain reaction (PCR) screening as a de-escalation tool for anti-MRSA therapy, given its high negative predictive value. While pharmacist involvement in antimicrobial stewardship has demonstrated benefits, limited data exist on pediatric pharmacy-driven MRSA nasal PCR protocols.
Methods: A single-center, pre- and post-interventional, retrospective cohort study included pediatric patients who received MRSA nasal PCR testing during two study periods: March 1–July 31, 2024 (pre-implementation) and March 1–July 31, 2025 (post-implementation). The primary outcome was the median duration of anti-MRSA antibiotic therapy before versus after protocol implementation. Secondary outcomes included pharmacist-ordered or documented MRSA PCRs, duration of intravenous antibiotic therapy, hospital length of stay, escalation of care, suspected or confirmed infection types, empiric and oral antibiotic selection, culture acquisition and results, and diagnostic performance of MRSA nasal PCRs, including sensitivity, specificity, positive predictive value, and negative predictive value.
Results: A total of 283 patients were included (pre-intervention n=134; post-intervention n=149). Median duration of intravenous anti-MRSA therapy was unchanged (1 [IQR 1–2] vs 1 [1–1] days; p=0.90). However, total MRSA antibiotic duration decreased (2 [1–6] vs 1 [1–5] days; p=0.01), as did total antibiotic duration (9 [7–14] vs 8 [6–12] days; p=0.02). Hospital length of stay was also reduced (median 3 vs 2 days; p<0.01). No significant differences were observed in culture acquisition, MRSA isolation rates, surgical interventions, or rates of therapy de-escalation. The MRSA PCR demonstrated high NPV (93.2% overall; 96.7% for pneumonia) but lower positive predictive value (PPV) (66.6% for SSTI; 20.0% for pneumonia).
Conclusion: Implementation of a pediatric pharmacy-driven MRSA nasal PCR protocol was associated with reductions in total MRSA and overall antibiotic duration, as well as shorter hospital length of stay, without adversely affecting clinical outcomes. These findings support the role of pharmacists in antimicrobial stewardship initiatives and highlight the clinical utility of MRSA PCR testing in pediatric populations.

Background: Penicillin and sulfonamide allergies are reported by many patients, yet most are not clinically significant. Documented allergies lead to the use of alternative agents such as fluoroquinolones, and this inappropriate use has been linked to increased rates of antimicrobial resistance. While studies have demonstrated the impact antibiotic allergies can have on patient outcomes and healthcare costs, there is minimal literature evaluating the influence documented allergies, whether true or not, may have on antimicrobial susceptibilities. The purpose of this study is to evaluate the relationship between documented antibiotic allergies and antimicrobial susceptibilities for gram-negative bloodstream isolates.

Methods: This is a multicenter, retrospective, cohort study of adult patients admitted to the Prisma Health System with confirmed gram-negative bacteremia from March 1, 2021, to August 1, 2025. The primary outcome is the difference in antibiotic susceptibilities (% susceptible vs % non-susceptible) of isolates between patients with and without documented beta-lactam allergies. Secondary outcomes include the difference in antibiotic susceptibilities among patients with and without fluoroquinolone and sulfonamide allergies and assessing variation in antimicrobial susceptibilities by severity of beta-lactam allergies. Baseline characteristics and outcomes were assessed using descriptive and inferential statistics.

Results: This retrospective cohort study included 500 patients, of which 92 had a beta-lactam allergy present on their chart. The most common bacteria isolated were E. coli (46%), K. pneumoniae (20%), P. mirabilis (10%), and P. aeruginosa (9%). For the primary outcome of rates of non-susceptible isolates in patients with and without a documented beta-lactam allergy, there was no statistically significant difference between the two groups for Enterobacterales or Pseudomonas species for any antimicrobials evaluated. However, patients with a beta-lactam allergy did have numerically higher rates of non-susceptible Enterobacterales isolates for cefazolin, ciprofloxacin,  and sulfamethoxazole-trimethoprim, with a difference of 5%, 5% and 9%, respectively. The secondary outcomes evaluating rates of non-susceptible isolates in patients with and without a fluoroquinolone allergy and with and without a sulfonamide allergy showed no statistically significant difference between groups. Lastly, when stratified by severity of beta-lactam allergy, it was found that patients with a high severity beta-lactam had the highest proportion of non-susceptible Enterobacterales isolates for ampicillin (67%). The medium severity beta-lactam allergy group had the highest proportion of non-susceptible isolates for ceftriaxone (29%), ciprofloxacin (43%), levofloxacin (100%), and sulfamethoxazole-trimethoprim (43%).

Conclusions: Overall, the presence of beta-lactam, fluoroquinolone, or sulfonamide allergies did not impact antibiotic susceptibilities. Almost half of beta-lactam allergies were documented as an “unknown” reaction which emphasizes the improvements that can be made in allergy documentation and reconciliation. This study was limited by the small population of patients with fluoroquinolone or sulfonamide allergies, the subjective manner of allergy assessment, and the process of manual chart review.

Title: Impact of Antibiotic Therapy on Weight in Adult Patients

Authors: Nghi Nguyen, Kate O’Connor, Joshua Eudy, Elizabeth Spitzer, Bintaben Patel, Emmie Wu, Daniel Anderson

Objective: To evaluate short‑ and long‑term weight changes and metabolic effects associated with antibiotic use in adults.

Background: Approximately 80–90% of antibiotic prescriptions occur in the outpatient setting, and an estimated 30% are considered inappropriate. This unnecessary overuse of antibiotics is often cited as a risk factor for increased rates of antimicrobial resistance and adverse drug events. Another often-overlooked consequence of antibiotic use is gut dysbiosis, a disruption of the microbial composition involved in host energy metabolism, such as modulation of Glucagon-like peptide-1 (GLP-1). As such, gut dysbiosis associated with antibiotic exposure may contribute to unintended weight gain. While pediatric studies have linked early and broad-spectrum antibiotic exposure to increased rates of obesity by age five, data on weight and metabolic changes following antibiotic exposure in adults are limited. Understanding these long‑term physiological effects is necessary to support personalized antimicrobial stewardship and improve shared decision-making with patients in the ambulatory care setting.

Method: This was a single-center retrospective cohort study evaluating adult patients at the Wellstar MCG Health Internal Medicine Clinic between December 1, 2024, and February 28, 2025. Cohorts included patients who received at least three days of antibiotics and those who received no antibiotics. Patients were excluded if they were prescribed a GLP-1 receptor agonist, if they were pregnant or postpartum during the inclusion window, had a recent major surgery, had prolonged hospitalization (intensive care unit stay > 72 hours and/or medical‑surgical unit admission > seven days), active cancer treatment, or uncontrolled HIV. The primary outcome was the change in weight from baseline at 12-months. Secondary outcomes included weight changes at three and six months and changes in A1C at six and twelve months. Statistical analysis was completed using an independent t-test for continuous data and a chi-squared test for categorical data.

Results: A total of 158 patients were included (66 antibiotic‑exposed and 92 controls). Baseline characteristics were balanced, although a higher proportion of patients in the antibiotic arm were receiving medications with potential for weight gain than in the control arm (54.5% and 27.2%, respectively). Antibiotic‑exposed patients also had a higher median number of clinic visits per year than controls: 8.5 and 6.5 visits. Patients received a mean of 2.8 antibiotic courses and a median of 15 days per course. Amoxicillin/clavulanate, azithromycin, and doxycycline were the most frequently prescribed antibiotics. There was no difference in weight change at 12 months between the antibiotic and no-antibiotic groups (0.84 kg vs -0.2 kg, p=0.16). No differences were observed in weight at three or six months, nor in A1C at six and twelve months.

Conclusion: There was no difference in 12‑month weight change between antibiotic-exposed and unexposed adults. However, this data indicates a need for further investigations that include a prolonged follow-up period, targeted evaluation of high-dysbiosis-risk antibiotics, and cumulative antibiotic consumption, while accounting for exposure to other weight-impacting factors such as medications and comorbid conditions.  

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Background: Urinary tract infections (UTIs) are among the most common bacterial infections worldwide, with Enterobacterales being the predominant pathogens. The rise in prevalence of extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) has led to increased antimicrobial resistance and recurrence rates. This prompts evaluation of alternative treatments such as amoxicillin-clavulanate, in which clavulanate may restore amoxicillin activity against common ESBL enzymes. The IDSA 2024 Antimicrobial-Resistant Gram-Negative guidelines recommend against its use but fail to cite high-quality evidence studying its efficacy in UTIs caused by ESBL-E. Other studies, limited by small sample size, suggest clinical efficacy of amoxicillin-clavulanate in the treatment of UTI caused by ESBL-E. This study attempts to bolster the body of data showing amoxicillin-clavulanate can be as effective as standard of care (SOC) antibiotics for the treatment of UTI caused by ESBL-E. 

Methods: This multi-site, retrospective cohort study is approved by the Institutional Review Board. Adult patients (≥18 years) with either uncomplicated or complicated UTI with a urine culture positive for ESBL-E (confirmed via susceptibility testing) treated between April 1, 2024, and July 1, 2025, at Atrium Health Wake Forest Baptist facilities were included. Patients must have received at least 72 hours of amoxicillin-clavulanate or SOC therapy. Patients were excluded if they had concurrent bacterial infections, polymicrobial urine cultures, a previous UTI within 90 days already captured in the dataset, anatomic urinary tract abnormalities or instrumentation, renal abscesses, prostatitis, received in-vitro active antibiotic lead-in therapy for >50% of treatment duration, were immunosuppressed, or used methenamine or antibiotics for prophylaxis. The primary endpoint is clinical failure within 90 days, defined as retreatment with antibiotics and either recurrence of UTI symptoms or a repeat urine culture positive for the same organism as the index infection. Secondary endpoints include recurrence of resistant organisms (carbapenem-resistant Enterobacterales, SOC-resistant, or amoxicillin-clavulanate-resistant strains) within 90 days and time to clinical failure. Chi-square or Fisher’s exact tests tested categorical variables, and t-tests or Mann-Whitney U tests will test continuous variables. Kaplan-Meier survival analysis and Cox regression will assess time-to-event outcomes, and multivariable analysis will be used to identify patient factors associated with clinical failure. 

Results: A total of 688 patients were screened; 274 patients met the inclusion criteria and were analyzed. Fifty-four patients were included in the amoxicillin-clavulanate group, and 220 in the SOC group. No statistically significant difference was observed in the primary outcome of treatment failure between the SOC and amoxicillin-clavulanate groups (p = 0.11). Patients with a prior history of ESBL infection had more than twice the odds of treatment failure (OR 2.09; p = 0.04), a finding that remained significant after adjustment for antibiotic selection and UTI type (OR 2.11, p = 0.047). Additionally, the use of sulfamethoxazole-trimethoprim for treatment of the index infection was associated with an 80% reduction in clinical failure compared to amoxicillin-clavulanate (p = 0.008). 

Conclusions: Among patients treated with antibiotics for urinary tract infections caused by ESBL-producing Enterobacterales species, there was no statistical difference in effectiveness between amoxicillin-clavulanate and SOC within the limits of this study design.

Outcomes Associated with Implementation of an Electronic Health Record Based Automatic Infectious Disease Consultation for Positive Blood Cultures with Staphylococcus aureus 

Authors: Taylor Bird, Elise Richoux, Brandon Hawkins, Samantha Walker, Miller Hadley, Amber Wolfe 

Background: 
Staphylococcus aureus bacteremia is often associated with high rates of morbidity and mortality if not managed appropriately. Infectious Diseases (ID) involvement in the clinical care of these patients has demonstrated reduced mortality, with early ID consultation also associated with decreased hospital length of stay. This study aims to evaluate the impact of an automatic electronic-health record (EHR) based ID consultation for patients with S. aureus bacteremia. This study will assess whether the automatic ID consultation protocol improves hospital length of stay, time to ID consultation, and time to targeted therapy.  

Methods:
This single-center, retrospective, observational cohort study evaluated the impact of an EHR based automatic infectious disease consultation order for patients with S. aureus bacteremia. This protocol was implemented July 1, 2024. The pre-intervention group was composed of hospital encounters from June 1, 2022 through May 31, 2024, while the post-intervention group contained hospital encounters from July 1, 2024 through April 30, 2025. The primary outcome evaluated overall hospital length of stay. Secondary outcomes included time to ID consultation, time to targeted therapy, and pharmacist interventions recommending ID consultation. Potential subjects were identified via a list generated from clinical surveillance software (TheraDoc). List composition components included patients with at least one positive blood culture for S. aureus. Patients were included in the study, if they were 18 years of age or older and received an ID consultation during the related hospitalization. Exclusion criteria included death or transition to hospice within 48 hours of a positive culture result, patient directed discharge prior to clinical stability, or consult communication to the ID service greater than 24 hours after the EHR automatically ordered an ID consult. Statistical analysis will be performed using SPSS (IBM). Categorical data will be analyzed using Chi-Square or Fisher’s Exact tests. Continuous data will be analyzed using Student’s t-test or Mann-Whitney U test, as appropriate.  

Results:
Hospital length of stay was significantly shorter in the post-intervention groups as compared to the pre-intervention group (15.3 vs 19.1 days p = 0.01). Time to ID consultation was not significantly different, with a mean of 0.38 ± 1.35 days in the pre-intervention group compared to 0.52 ± 0.48 days in the post-intervention groups (p = 0.226). Time to targeted antibiotic therapy was significantly shorter in the post-intervention group with a mean of 2.40 days compared to 2.90 days in the pre-intervention group (p = 0.039). Pharmacy interventions recommending ID consultation were significantly lower in the post-intervention group (5.7% vs 0%; p = 0.001).

Conclusions: 
The implementation of an electronic health record based automatic infectious disease consultation protocol for Staphylococcus aureus bacteremia resulted in significant reductions in overall hospital length of stay and decreased the time to targeted antibiotic therapy. 

BACKGROUND 
Linezolid is an oxazolidinone antibiotic with activity against drug-resistant gram-positive organisms, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus. The typical duration of linezolid therapy is approximately two weeks, with a maximum recommended duration of 28 days per the package insert. Bone and joint infections often require prolonged courses of antimicrobial therapy of 4 to 6 weeks. Linezolid is an ideal agent for treatment of bone and joint infections due to its reliable oral bioavailability and activity against resistant organisms. However, concerns regarding hematologic and neurologic toxicity often limit extended use beyond recommended durations. Real-world data describing tolerability during prolonged outpatient therapy remains limited. This study evaluated treatment completion and adverse effects associated with extended-duration linezolid therapy in an outpatient cohort. 
METHODS 
We conducted a retrospective cohort study at a large academic medical center evaluating adults prescribed oral linezolid 600 mg every 12 hours for more than 14 days for bone and joint infections between January 2022 and December 2024. Laboratory data were evaluated at two-week intervals. Patients lacking follow up laboratory data after the first 14 days of therapy or who were lost to follow up were excluded. Baseline demographics, laboratory values, duration of therapy, and adverse effects were collected from electronic health records. The primary outcome was the completion of prescribed therapy. Secondary outcomes included incidence of hematologic toxicity, defined as thrombocytopenia (platelet count < 150 x 103/ mcL or 50% decrease from baseline) or anemia (hemoglobin ≤ 10 g/dL or 2 g/dL decrease from baseline), and neurologic toxicity defined by documented new-onset neuropathic or visual symptoms. Time to adverse events was also assessed. 

BACKGROUND: Sepsis is a leading cause of hospital morbidity and mortality. While current Surviving Sepsis Guidelines emphasize early broad-spectrum antibiotic administration, they do not address sequencing. Evidence suggests that delays in gram negative coverage, against Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa, are associated with increased mortality, and administration of broad-spectrum beta lactams prior to vancomycin may improve survival. In practice, initiation of antibiotic therapy is delayed due to lack of IV access, blood culture collection, medication verification, and absence of standardized order sets. These limitations are greater among spinal cord (SCI) and traumatic brain injury (TBI) patients who have atypical presentations complicating early sepsis recognition. The aim of this study is to assess the order of appropriate antibiotic administration, delays in administration from lack of intravenous (IV) access, and timing of blood culture collection to support creation of a sepsis order set.

METHODS: This is a single-center, retrospective, quality improvement project performed at a rehabilitation center. Patients (≥18 years) admitted between July 1, 2023, and July 31, 2025, who met systemic inflammatory response (SIRS) criteria and received IV vancomycin and one gram-negative agent for sepsis or neutropenic indications were included. Patients were excluded if antibiotic timing was inadequately documented.
Data collected included patient demographics, injury type (SCI or TBI), sepsis indicators, timing of sepsis recognition, antibiotic timing and sequencing, blood culture collection, lactate measurement, IV fluid resuscitation, and IV access placement.  

The primary outcome was sequencing, including gram-negative coverage first followed by gram-positive coverage antibiotics. Secondary outcomes included time between gram-negative and gram-positive therapy, percentage of patients with cultures drawn before antibiotic administration, frequency of IV-related delays, and type of IV line. Data was analyzed using descriptive statistics. 

RESULTS: A total of 65 patients meeting SIRS inclusion criteria were evaluated. The median age was 34 years old (SD 18.8), with males comprising 81.5% of the cohort (n=53). Injury classifications included SCI (n=24, 37%), TBI (n=26, 41.5%), and dual (n=14, 21.5%) diagnoses.
When vancomycin was administered prior to gram-negative therapy, the mean delay to gram-negative coverage was 141 minutes. Upon further analysis, vancomycin was administered first in 15.4% of encounters, while gram negative agents were more frequently administered first, including piperacillin-tazobactam (57%), cefepime (20%), and meropenem (7.6%).  

In 20% of encounters, blood cultures were either obtained after the first antibiotic dose or not obtained. IV access was not established prior to antibiotic ordering in 46.2% of patients. Antibiotics were administered via peripheral IV (75%), midline (11%), or peripherally inserted central catheter (14%). 

CONCLUSIONS: Administering vancomycin first resulted in an expected delay of more than two hours before effective gram-negative coverage. This delay was likely due to the standard vancomycin infusion time at this facility. Because delays in antibiotic administration increase mortality in sepsis, education on Y-site compatibility is essential to allow compatible agents to be administered simultaneously and facilitate faster, more efficient antibiotic delivery. Moreover, 20% of blood cultures were collected inappropriately, compromising diagnostic accuracy and limiting targeted antibiotic therapy, highlighting the need for reinforcement of proper culture collection.

Additionally, nearly half of patients meeting sepsis criteria at the time of antibiotic ordering did not have IV access, reflecting a challenge unique to rehabilitation settings, where the goal is early discontinuation of IV lines to enhance mobility, minimize line associated complications, and support functional recovery. However, for sepsis, a delay in IV access inadvertently leads to a delay in antibiotic administration. 
These findings show inconsistent sepsis workflows and clinically relevant delays which can impact patient outcomes, highlighting the need for a standardized sepsis order set in rehabilitation hospitals to streamline IV access, culture collection, and appropriate antibiotic prioritization. 

Background: 

• Intra-abdominal infections (IAIs) are a frequent cause of hospitalization which occasionally require empiric broad-spectrum antibiotic use. Despite current guidelines indicating that P. aeruginosa is uncommon in low-risk, community-acquired IAI, antipseudomonal agents remain frequently prescribed. This unnecessary use increases risks of nephrotoxicity, resistance, and higher healthcare costs.2 For low-risk patients without significant comorbidities, healthcare exposure, or septic shock, narrower regimens are recommended.1 Persistent inappropriate prescribing highlights an opportunity for targeted antimicrobial stewardship interventions to optimize empiric therapy, improve patient outcomes, and reduce unnecessary broad-spectrum exposure. 

Objectives: 

• Evaluate the impact of pharmacy-led provider education on reducing inappropriate antipseudomonal antibiotic use in patients with low-risk intra-abdominal infections 

• Primary outcome: Percentage difference of patients receiving antipseudomonal antibiotics before and after the intervention 

• Secondary outcomes: Days of therapy (DOT) per 1,000 patient days, hospital length of stay, incidence of C. difficile infection, and identification of P. aeruginosa on culture during hospitalization, impact of infectious disease (ID consult) on de-escalation 

Methods: 

• Retrospective chart review approved by the local Institutional Review Board (IRB) 

• Chart review to evaluate empiric antibiotic use in adult patients with low-risk intra-abdominal infections (IAIs), as defined by the 2024 Surgical Infection Society guidelines. 

• During the pre-intervention period between May 1st, 2025 and September 30th, 2025, patients are assessed for documented infection diagnosis and empiric antibiotic selection to determine the frequency of antipseudomonal antibiotic use. Data gathered from this review is used to develop an educational presentation for hospitalist providers to highlight recommended therapy for low-risk IAI. 

• A post-intervention chart review between November 1st, 2025 and March 30th,  2026 will be performed to reassess prescribing practices 

• Inclusion criteria 

• Age ≥18 

• Admitted to Baptist Health Lexington with primary diagnosis of diverticulitis, peritonitis, cholecystitis, cholangitis, pancreatitis, or appendicitis 

• Received antimicrobial therapy 

• Exclusion criteria 

• Pregnant or incarceration. Met criteria for high-risk infection (admitted to ICU during hospital stay, required surgical intervention, received IV antibiotics in previous 90 days, recent Pseudomonas culture, immunocompromised, post-operative infection or inadequate source control, age ≥ 80) 

Results: 

• Baseline characteristics were similar between pre- and post-intervention groups, with diverticulitis most common. The educational intervention did not significantly reduce inappropriate antipseudomonal use, which remained high. A numerical decrease in overall antimicrobial exposure was observed but was not statistically significant. No C. difficile testing or P. aeruginosa cultures were identified. Antimicrobial use shifted overall, driven by reduced ertapenem use, while other broad-spectrum agents remained common. Infectious disease consultation was associated with higher rates of de-escalation. 

Conclusions: 

• Provider education alone did not significantly reduce inappropriate antipseudomonal use in low-risk IAI. Persistent broad-spectrum prescribing suggests the need for more active stewardship strategies. The absence of P. aeruginosa supports guideline recommendations, and the impact of ID consultation highlights the value of multidisciplinary involvement. 

References 

1. The Surgical Infection Society Guidelines on the Management of Intra-Abdominal Infection: 2024 Update Jared M. Huston, Philip S. Barie, E. Patchen Dellinger, Joseph D. Forrester, Therese M. Duane, Jeffrey M. Tessier, Robert G. Sawyer, Miguel A. Cainzos, Kemal Rasa, Jeffrey G. Chipman, Lillian S. Kao, Frederic M. Pieracci, Kristin P. Colling, Daithi S. Heffernan, Janice Lester, and Therapeutics and Guidelines Committee  

1. Lodise TP, Izmailyan S, Olesky M, Lawrence K. An Evaluation of Treatment Patterns and Associated Outcomes Among Adult Hospitalized Patients With Lower-Risk Community-Acquired Complicated Intra-abdominal Infections: How Often Are Expert Guidelines Followed? Open Forum Infect Dis. 2020 Jun 19;7(7):ofaa237. doi: 10.1093/ofid/ofaa237. PMID: 32676511; PMCID: PMC7353956.