Microbiome Analysis in Penile Lichen Sclerosus: Urethral vs Preputial Samples

Overview

This study prospectively analyzed the penile microbiome in uncircumcised males with histologically confirmed lichen sclerosus (LS) compared to controls. Using standardized swab collection and molecular diagnostics, the investigation evaluated bacterial flora differences in urethral and preputial sites, alongside screening for HPV and other sexually transmitted pathogens.

Background

Lichen sclerosus is a chronic inflammatory condition predominantly affecting uncircumcised males, often leading to phimosis and urethral strictures. Its etiology remains unclear but may involve infection, chronic irritation, autoimmune factors, and urinary micro-incontinence. Previous microbiome studies in LS have been limited and inconclusive, particularly in males without urethral strictures. Understanding the penile microbiome's role could clarify LS pathogenesis and guide management.

Data Highlights

The study included uncircumcised males undergoing circumcision, excluding those with recent antibiotic or corticosteroid use. Swabs were collected from the coronal sulcus and urethra prior to surgery. Molecular assays detected 24 high- and low-risk HPV types and nine other sexually transmitted pathogens. Blood tests assessed CRP and hepatitis B and C status. Bacterial classification followed established urinary tract flora/pathogen criteria.

Key Findings

• Uncircumcised males with LS showed distinct penile microbiome profiles compared to controls with healthy foreskin.
• Common bacteria in the coronal sulcus included Corynebacterium spp., Prevotella, Staphylococcus, and others, consistent with prior studies.
• Pathogenic bacteria such as Staphylococcus aureus and Enterococcus spp. were more prevalent in uncircumcised men, potentially contributing to inflammation.
• HPV and other sexually transmitted infections were screened but their direct association with LS remains uncertain.
• Standardized sampling and exclusion of recent antimicrobial use strengthened the reliability of microbiome characterization.

Clinical Implications

Clinicians should recognize that penile LS is associated with altered microbiota, which may influence disease progression and response to treatment. Avoiding unnecessary systemic antibiotics is advisable to preserve physiological flora. Comprehensive microbiome assessment could inform targeted therapies and improve management of LS-related complications such as phimosis.

Conclusion

This study enhances understanding of the penile microbiome in lichen sclerosus, highlighting differences in bacterial communities between LS patients and controls. Further research is needed to elucidate causality and therapeutic implications.

References

1. Mändar et al. -- Classification of male urinary tract bacteria
2. Paganelli et al. 2023 -- Immune dysregulation and external factors in lichen sclerosus