Impact of different prophylactic antibiotics regimens on the risk of urinary tract infections after hysterectomies due to benign Indications: A retrospective cohort study.

OBJECTIVE This study aimed to evaluate the adequacy of current prophylactic antibiotic regimens and compare their effectiveness in preventing postoperative urinary tract infections (UTIs) following hysterectomies for benign indications.

METHODS This is a retrospective cohort study using the TriNetX dataset. A total of 153,818 women who underwent hysterectomies between January 2005 and September 2025 were included in this study. The prophylactic antibiotic regimens administered on the day of surgery were categorized as cefazolin, cefazolin + metronidazole, or gentamicin + clindamycin.

RESULTS After propensity score matching, 64,704 patients were included in each cohort to compare cefazolin + metronidazole and cefazolin only, and 12,205 patients were included in each cohort to compare cefazolin + metronidazole and clindamycin + gentamicin. The mean age ranged from 46.5 to 47.7 years across the groups. During the 6-month follow-up period, cefazolin + metronidazole was associated with a significantly lower risk of postoperative UTIs compared with cefazolin (hazard ratio [HR] = 0.92, 95% confidence interval [CI]: 0.88-0.97) and clindamycin + gentamicin (HR = 0.75, 95% CI: 0.67-0.84). The cefazolin plus metronidazole regimen was associated with a significantly lower risk of postoperative UTIs after laparoscopic and total hysterectomies but not after abdominal, vaginal, or subtotal hysterectomies. Sensitivity analysis restricted to 2015-2025 and to patients without a history of antibiotic allergy yielded consistent results.

CONCLUSION Cefazolin + metronidazole was associated with a lower UTI risk than cefazolin alone or clindamycin + gentamicin.