Preoperative penoscrotal swab microbiology and postoperative infection concordance in malleable penile prosthesis surgery: A prospective randomized study of skin antisepsis.

Abstract

Surgical site infection (SSI) remains a serious complication of penile prosthesis implantation despite established preventive strategies. This prospective single-center randomized clinical study evaluated the clinical relevance of pre-antisepsis penoscrotal skin swabbing in men undergoing malleable penile prosthesis implantation by assessing organism-level concordance, defined as species-level matching between preoperative penoscrotal swab isolates and postoperative infection-site cultures in patients who developed SSI, based on routine phenotypic microbiological identification. A secondary objective was to compare chlorhexidine gluconate (CHG) and povidone-iodine (PVI) with respect to downstream postoperative outcomes. Between October 2023 and February 2024, 135 men undergoing malleable penile prosthesis implantation at a single tertiary referral center were randomized 1:1 using a computer-generated block randomization sequence to CHG (n = 69; 2% chlorhexidine in 70% alcohol) or PVI (n = 66; 10% povidone-iodine). Preoperative penoscrotal swabs were obtained before surgical skin antisepsis, and all patients completed standardized 12-month follow-up. SSI occurred in 15/135 patients (11.1%). Organism-level concordance between preoperative swab isolates and postoperative infection-site cultures was observed in 11/15 infected patients (73.3%; 95% confidence interval, 45.0-92.2%). Staphylococcus epidermidis was the most frequent concordant organism, with matching preoperative and postoperative isolates in 7/9 postoperative S. epidermidis infections (77.8%; p = 0.02). Overall SSI rates did not differ significantly between CHG and PVI groups (8.7% vs 13.6%, p = 0.42). However, compared with CHG, the PVI group showed earlier infection onset (4 ± 1 vs 6 ± 2 days, p = 0.03), higher postoperative bacterial colony counts (3.8 × 10⁵ ± 0.7 × 10⁵ vs 1.8 × 10⁵ ± 0.4 × 10⁵ CFU/mL, p = 0.01), and longer epithelialization time (10.4 ± 2.1 vs 9.2 ± 1.8 days, p = 0.03). These findings suggest that preoperative penoscrotal swabbing may provide clinically relevant microbiological information in higher-risk malleable penile prosthesis candidates, while CHG-based antisepsis may enhance bacterial suppression and wound healing.