The Futility of Nugent Scoring as a Diagnostic Tool for Neovaginal Bacterial Dysbiosis in Transfeminine People

Background : Transfeminine people were assigned male at birth and experience a female or feminine gender identity. Many elect to undergo vaginoplasty, a surgical procedure that constructs a neovagina, typically using penile and scrotal tissue. Like cisgender females, transfeminine people experience gynecological symptoms, including pain, discharge, and malodor. In cisgender females, clinicians attribute these symptoms to bacterial dysbiosis and can be diagnosed by Nugent scoring of gram-stained vaginal smears. The Nugent score assesses the abundance of large gram-positive rod vs. small or curved gram-variable rod morphotypes, traditionally for the detection of Lactobacillus spp., Gardnerella vaginalis , and Mobiluncus spp. (curved rod), respectively. Although unvalidated for neovaginal samples, this method is frequently applied to diagnose dysbiosis in transfeminine people with vaginoplasty. Objective: This study assessed the Nugent score’s utility as a clinical tool for diagnosing neovaginal dysbiosis in transfeminine people who underwent penile inversion vaginoplasty. Study Design : As a part of the TransBiota study, n=39 transfeminine participants self-collected neovaginal smears. Smears were Gram stained and Nugent scored, and Nugent scores were correlated with existing data on neovaginal bacterial composition (16S rRNA gene sequencing), neovaginal cytokines (Luminex multiplex immunoassay), and self-reported symptoms. Results: More than 70% of smears fell in the 7-10 range that would indicate Bacterial Vaginosis in cisgender women. However, Nugent score failed to correlate with the abundance of Nugent-targeted bacteria. Bacteria with similar morphotypes, but not belonging to Lactobacillus , Gardnerella , or Mobiluncus , were highly abundant and prevalent in the neovagina. Nugent score also failed to predict local inflammation or clinical symptoms. Conclusion : The Nugent score is not an effective tool to identify neovaginal dysbiosis or indicators of health in transfeminine individuals. Clinicians need the development of accurate, evidence-based diagnostic tools for the neovagina.