Prophylactic antibiotic regimen and risk of surgical site infection in patients undergoing hysterectomy for benign disease: a retrospective cohort study

Objective To evaluate the association between prophylactic antibiotic regimen (cefazolin alone vs. cefazolin plus metronidazole) and the occurrence of surgical site infections (SSIs), as well as infection severity and management, in patients undergoing hysterectomy for benign disease. Methods A retrospective cohort study was conducted at a tertiary care center, including women undergoing hysterectomy for benign indications. Patients receiving cefazolin alone were compared with those receiving cefazolin plus metronidazole. The primary outcome was overall SSIs. Secondary outcomes included infection severity (superficial, deep, organ/space) and type of management (medical vs. surgical). Crude associations were estimated using contingency tables, and adjusted odds ratios were obtained through multivariable logistic regression including clinically relevant covariates. Results A total of 1,069 patients were included, of whom 512 received cefazolin alone and 557 received cefazolin plus metronidazole. In the adjusted analysis, the combined regimen was not associated with a reduced risk of SSIs (aORs: 1.02; 95% CI: 0.60–1.76; p = 0.93). Among patients with SSIs ( n = 58), the use of cefazolin plus metronidazole was associated with lower infection severity (aORs: 0.20; 95% CI: 0.05–0.76; p = 0.01) and a reduced likelihood of requiring surgical management (aORs: 0.11; 95% CI 0.02–0.49; p = 0.007). Conclusion The addition of metronidazole to cefazolin was not associated with a reduction in overall SSIs incidence after hysterectomy for benign disease. However, it was associated with lower infection severity and reduced need for surgical reintervention among patients who developed SSIs, suggesting a potential benefit in reducing postoperative morbidity.