Use and Effectiveness of Peri-Operative Cefotetan versus Cefazolin Plus Metronidazole for Prevention of Surgical Site Infection in Abdominal Surgery Patients

Background: Current practice guidelines for antimicrobial prophylaxis in surgery recommend a cephamycin or cefazolin plus metronidazole for various abdominal surgeries. In February 2016, cephamycin drug shortages resulted in a change in The Johns Hopkins Hospital's (JHH) recommendation for peri-operative antibiotic prophylaxis in abdominal surgeries from cefotetan to cefazolin plus metronidazole. The primary objective of this study was to quantify the percentage of abdominal surgeries adherent to JHH peri-operative antibiotic prophylaxis guidelines. A sub-group analysis investigated whether prophylaxis with cefazolin plus metronidazole was associated with a lower rate of surgical site infections (SSIs) versus cefotetan. Patients and Methods: This retrospective cohort study included adult inpatients who underwent an abdominal surgery at JHH in September 2015 (Study Period I: cefotetan) or February to March 2016 (Study Period II: cefazolin plus metronidazole). Results: Two hundred abdominal surgery cases were included in the primary analysis. A subset of 156 surgical cases were included in the sub-group analysis. The overall adherence rate to JHH guidelines was 75% in Study Period I versus 17% in Study Period II (p < 0.001). The largest difference in adherence was attributed to pre-operative administration time (87% vs. 23%, p < 0.001), primarily because of the longer infusion time required for metronidazole. Surgical site infections occurred in 14% (12/83) of surgeries with cefotetan versus 8.2% (6/73) with cefazolin plus metronidazole for prophylaxis (p = 0.19). Conclusions: Adherence to an institution-specific peri-operative antibiotic prophylaxis guideline for abdominal surgeries was limited primarily by the longer infusion time required for pre-operative metronidazole. A higher percentage of SSIs occurred among abdominal surgeries with cefotetan versus cefazolin plus metronidazole for prophylaxis.