Comparative Effectiveness of Single versus Combination Antibiotic Prophylaxis for Infections after Transrectal Prostate Biopsy.

An increase in fluoroquinolone resistance and transrectal ultrasound-guided prostate (TRUS) biopsy infections has prompted the need for alternative effective antibiotic prophylaxis. We aimed to compare ciprofloxacin and other single-agent therapies to combination therapy for efficacy and adverse effects. Men who underwent a TRUS biopsy within the VA Boston health care system with documented receipt of prophylactic antibiotics periprocedure were eligible for inclusion. Postprocedure infections within 30 days were ascertained by chart review from electronic records, including any inpatient, outpatient, or urgent-care visits. Among 455 evaluable men over a 3-year period, there were 25 infections (5.49%), with sepsis occurring in 2.4%, urinary tract infections (UTI) in 1.54%, and bacteremia in 0.44% of patients. Escherichia coli was the most common urine (89%) and blood (92%) pathogen, with fluoroquinolone resistance rates of 88% and 91%, respectively. Ciprofloxacin alone was associated with significantly more infections than ciprofloxacin plus an additional agent (P = 0.014). Intramuscular gentamicin alone was also significantly associated with a higher infection rate obtained with all other regimens (P = 0.004). Any single-agent regimen, including ciprofloxacin, ceftriaxone, or gentamicin, was associated with significantly higher infection rates than any combination regimen (odds ratio [OR], 4; 95% confidence interval [CI], 1.47, 10.85; P = 0.004). Diabetes, immunosuppressive condition or medication, hospitalization within the previous year, and UTI within the previous 6 months were not associated with infection risk. Clostridium difficile infections were similar. These findings suggest that ciprofloxacin, ceftriaxone, and gentamicin alone are inferior to a combination regimen. Institutions with high failure rates of prophylaxis for TRUS biopsies should consider combination regimens derived from their local data.