How do different antibiotic coating/dipping strategies affect penile implant infection and revision rates in randomized or registry data?
Executive summary
Antibiotic-impregnated/coated penile implants and intraoperative antibiotic “dips” or irrigations are associated in registry and retrospective series with large reductions in infection and consequent revision/explantation rates compared with uncoated devices, while emerging comparative data—largely non-randomized or ex vivo—suggests specific dip combinations (vancomycin + gentamicin) outperform alternatives such as rifampin-containing mixes or chlorhexidine alone; however, high-quality randomized trials directly comparing coating/dip strategies remain limited and outcomes vary by patient risk strata (eg, diabetes, revision surgery) [1] [2] [3] [4].
1. Coatings moved the baseline — dramatic population-level drops in infections
The single biggest change in the last two decades is the broad adoption of infection-retardant coatings on inflatable penile prostheses (IPP): multicenter and review data report device infection rates falling by roughly half since coatings became standard and, in experienced hands, to well under 1% in contemporary series (previously 3–5% or higher) [1] [2] [3] [5]. This shift translates directly into fewer explantations and revisions in registry and large-series data, establishing coating as the dominant population-level driver of risk reduction [1] [5].
2. Dips and irrigations still matter — registry/series suggest additive benefit and choice matters
Large multicenter cohorts and observational studies of Coloplast Titan and other hydrophilic devices show that intraoperative dipping/irrigation solutions remain important even with coated devices: multiple high-volume centers reported that dipping with vancomycin + gentamicin was associated with lower postoperative infection, explantation, and revision rates compared with alternatives such as rifampin + gentamicin or polymyxin-containing mixes, particularly in higher-risk subgroups like diabetic patients [2] [4] [6]. A 2020 multicenter investigation and subsequent reviews highlight that VG (vancomycin/gentamicin) dipping correlated with the best observed clinical outcomes across several series [2] [4] [6].
3. Head-to-head evidence is limited; much comes from retrospective/registry observation or ex vivo testing
Despite consistent signals favoring certain combinations, randomized controlled trial evidence specifically comparing coating/dip regimens is sparse: most comparisons are retrospective, registry-based, prospective non-inferiority pilots, or ex vivo microbiologic assays rather than large RCTs with clinical endpoints [7] [3] [8]. For example, recent ex vivo and in vitro work showed VG had superior antimicrobial activity on hydrophilic surfaces versus 0.05% chlorhexidine gluconate (CHG) or normal saline, but translation of microbiologic superiority to long-term clinical revision rates requires more prospective clinical data [8]. A two-center randomized non-inferiority study comparing 0.05% CHG monotherapy to conventional antibiotic irrigation reported preliminary results but broader randomized data are still lacking [7].
4. Not all antibiotic choices are equal — signals that rifampin may be less favorable and context matters
Several reviews and cohort analyses flagged an unexpected association: inclusion of rifampin in dipping protocols correlated with higher infection rates in some series, a finding authors hypothesize could reflect shifts in microbial ecology or resistance rather than a direct causal harm from rifampin itself [6] [4]. This underlines that device coating chemistry, dip choice, local microbiology, and patient factors (eg, diabetes, prior revisions, operative time) interact — what “works best” in one registry may not replicate elsewhere without accounting for these variables [6] [2].
5. Practical implications, limitations, and where evidence should go next
Current practice—preoperative systemic antibiotics plus coated devices and targeted intraoperative dips like vancomycin/gentamicin—rests on consistent observational benefit in registry and multicenter series and mechanistic lab data, but it is not yet underpinned by robust randomized trials that definitively rank dip/coating strategies for clinical infection and revision endpoints across risk groups; major reviews therefore call for prospective randomized or registry-embedded trials and for pathogen-focused strategies guided by sequencing data to refine coatings and dips [3] [7] [2]. Until such trials are done, the strongest, reproducible conclusion from available data is that coatings plus judicious perioperative systemic and intraoperative topical antibiotics markedly reduce infection and revisions, and among dipping options VG currently has the most consistent favorable signal in multicenter and laboratory reports [1] [2] [8] [6].