Transperineal prostate biopsy without routine antibiotics: Infection risk and ethnicity in a diverse urban cohort

Introduction: Transperineal prostate biopsy (TPPB) is associated with lower infectious risk than the transrectal approach, prompting reconsideration of routine antibiotic prophylaxis. In March 2024, our institution implemented a protocol change from universal prophylaxis to selective omission of antibiotics for eligible patients undergoing TPPB under local anaesthesia. This study evaluated post-biopsy infection outcomes following this change and explored demographic and procedural factors associated with infection risk. Methods: A retrospective cohort study was conducted at a district general hospital serving a diverse urban population. Consecutive patients undergoing TPPB between May 2023 and April 2025 were included. Patients were categorised according to receipt of prophylactic antibiotics before and after protocol implementation. The primary outcome was infection within 30 days, defined as fever, urinary tract infection, or sepsis requiring antibiotic treatment. Categorical variables were compared using Fisher’s exact test. Results: A total of 306 patients were included, with 153 in each group. Overall infection incidence was 3.3% (10/306). Infection occurred in 7 of 153 patients (4.6%) receiving antibiotics and in 3 of 153 patients (1.9%) managed without antibiotics (p = 0.335). Most infections were caused by Gram-negative organisms. No statistically significant associations were observed between infection and age, ethnicity, or biopsy core number. Infection rates remained low across demographic subgroups. Conclusions: Selective omission of antibiotic prophylaxis for TPPB under local anaesthesia was not associated with an increased risk of infection. These findings support antimicrobial stewardship initiatives and reinforce the safety of antibiotic-free transperineal biopsy in appropriately selected patients.