2026 Southeastern Residency Conference

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.