Penile prostheses harbor biofilms driven by individual variability and manufacturer even in the absence of clinical infection

Abstract

Background: Culture-based studies have shown that penile prostheses harbor biofilms in the presence and absence of infection, but these findings have not been adequately validated using contemporary microbiome analytic techniques.

Aim: The study sought to characterize microbial biofilms of indwelling penile prosthesis devices according to patient factors, device components, manufacturer, and infection status.

Methods: Upon penile prostheses surgical explantation, device biofilms were extracted, sonicated, and characterized using shotgun metagenomics and culture-based approaches. Device components were also analyzed using scanning electron microscopy.

Outcomes: Outcomes included the presence or absence of biofilms, alpha and beta diversity, specific microbes identified and the presence of biofilm, and antibiotic resistance genes on each prosthesis component.

Results: The average age of participants from whom devices were explanted was 61 ± 11 years, and 9 (45%) of 20 had a diagnosis of diabetes mellitus. Seventeen devices were noninfected, and 3 were associated with clinical infection. Mean device indwelling time prior to explant was 5.1 ± 5.1 years. All analyzed components from 20 devices had detectable microbial biofilms, both in the presence and absence of infection. Scanning electron microscopy corroborated the presence of biofilms across device components. Significant differences between viruses, prokaryotes, and metabolic pathways were identified between individual patients, device manufacturers, and infection status. Mobiluncus curtisii was enriched in manufacturer A device biofilms relative to manufacturer B device biofilms. Bordetella bronchialis, Methylomicrobium alcaliphilum, Pseudoxanthomonas suwonensis, and Porphyrobacter sp. were enriched in manufacturer B devices relative to manufacturer A devices. The most abundant bacterial phyla were the Proteobacteria, Actinobacteria, and Firmicutes. Glycogenesis, the process of glycogen synthesis, was among the predominant metabolic pathways detected across device components. Beta diversity of bacteria, viruses, protozoa, and pathways did not differ among device components.

Clinical implications: All components of all penile prostheses removed from infected and noninfected patients have biofilms. The significance of biofilms on noninfected devices remains unknown and merits further investigation.

Strengths and limitations: Strengths include the multipronged approach to characterize biofilms and being the first study to include all components of penile prostheses in tandem. Limitations include the relatively few number of infected devices in the series, a relatively small subset of devices included in shotgun metagenomics analysis, and the lack of anaerobic and other expanded conditions for culture.

Conclusion: Penile prosthesis biofilms are apparent in the presence and absence of infection, and the composition of biofilms was driven primarily by device manufacturer, individual variability, and infection, while being less impacted by device component.

Keywords: bacteria; biofilm; colonization; microbiota; penile prosthesis.