The Neovaginal microbiome
The neovaginal microbiome presents a unique and complex bacterial environment shaped by the surgical creation of a neovagina, which involves penile inversion, scrotal grafts, or sigmoid colon grafts.
Unlike cis women’s vaginal microbiomes, which are dominated by Lactobacillus species that maintain a protective acidic environment, neovaginal microbiomes display greater bacterial diversity.
Why is the neovaginal microbiome different?
This diversity arises from the interplay between penile, scrotal, and, in some cases, intestinal tissue microbiomes, combined with hormonal, mechanical, and environmental changes following surgery.
Neovaginas often feature anaerobic bacteria like Porphyromonas, Prevotella, and Peptostreptococcus, which are associated with bacterial vaginosis (BV) in cis women. Additionally, unique species such as Eikenella and Anaeroglobus, potentially introduced through oral-genital contact or tissue origins, are also observed.
What are the tendencies of the neovaginal microbiome?
While the diversity is intriguing, it may contribute to inflammation, immune challenges, and a higher susceptibility to infections compared to the typical vaginal environment.
Immune and inflammatory responses in neovaginas reveal significant differences compared to cis women’s vaginas.
Protein analysis shows neovaginas have decreased keratinisation and reduced barrier function, likely due to the lack of estrogen-driven maintenance of the tissue.This can lead to compromised structural integrity, increasing the risk of tearing, irritation, and infections.
Furthermore, antimicrobial proteins such as lipocalin-2, which regulate microbial inflammation, are diminished in neovaginas. This deficit may exacerbate microbial-driven inflammation and compromise the immune response.
Unique microbial functions, such as vitamin B6 metabolism by neovaginal bacteria, are associated with inflammation and immune system inefficiencies, potentially worsening the neovagina’s vulnerability to infections and irritation.
The similarities with the cos female vaginal microbiome
The findings suggest that neovaginas are more similar to polymicrobial or BV-like environments in cis women than the Lactobacillus-dominated microbiomes typical of cis vaginal health.
These differences underscore the importance of tailored care for neovaginal health, including potential hormonal supplementation to support barrier function and targeted strategies to mitigate bacterial overgrowth or inflammation.