Extra reading citations for genital flora Flashcards
Dysbiosis refers to an imbalance in the microbiota
A systematic review on The Role of Genital Tract Microbiome in Fertility found significant study from India used culture-based techniques to compare the vaginal microbiota of infertile and healthy women. They found a high prevalence of asymptomatic bacterial vaginosis in infertile patients, along with a lower rate of beneficial Lactobacillus bacteria.
certain Lactobacillus species were associated with better pregnancy rates. Gardnerella vaginalis was linked to poorer outcomes.
Studies also explored the impact of sexual intercourse on the vaginal microbiome of infertile couples. They found that sexual activity could lead to microbial shifts, particularly in couples where one partner had inflammatory prostatitis, potentially affecting fertilization.
infertile women exhibited lower proportions of aerobic and anaerobic bacteria. Notably, Chlamydia trachomatis infection was more prevalent in infertile women and correlated with a decrease in Lactobacillus species.
Miscellaneous findings included a higher prevalence of Escherichia coli in primary infertility and consistent microbial compositions across the vagina, cervix, and endometrium. Lactobacillus presence in human follicular fluid correlated with better IVF outcomes, while contaminant bacteria adversely affected fertilization rates.
Overall, these studies underscore the complex interplay between the microbiome and infertility, offering insights into potential therapeutic interventions and highlighting the need for further research in this evolving field
Vitale et al. (2021)
In this study, researchers observed an increased colonization of certain bacteria associated with bacterial vaginosis (BV) in women who opted for copper intrauterine devices (IUDs) compared to other contraceptive methods
(Achilles et al., 2018).
Estrogen plays a crucial role in shaping the vaginal microenvironment. It promotes the proliferation and maturation of vaginal epithelial cells, increasing the thickness of the epithelium.
Estrogen also stimulates the production of glycogen by these cells. Shedding of glycogen-rich epithelial cells into the vaginal lumen provides a carbon source for beneficial Lactobacillus bacteria, which metabolize it into lactic acid, lowering the vaginal pH and inhibiting the growth of pathogens like Neisseria gonorrhoeae, Chlamydia trachomatis, and those associated with bacterial vaginosis (BV).
Lactobacilli further prevent pathogen colonization through the production of bacteriocins and biosurfactants.
In the absence of Lactobacillus dominance, the vaginal microbiota becomes diverse, with anaerobic bacteria such as Atopobium, Prevotella, and Gardnerella colonizing the environment, resembling BV. Molecular BV, characterized by a deficiency in lactobacilli, is linked to impaired epithelial maturation, increased mucosal inflammation, altered epithelial barrier function, heightened susceptibility to sexually transmitted infections (STIs) like chlamydia, gonorrhea, HIV, HPV, and reproductive risks.
Testosterone therapy effectively induces the development of masculine secondary sex characteristics in transgender and gender diverse (TGD) individuals. However, it can lead to thinning of the vaginal epithelium due to estrogen suppression, resembling post-menopausal vaginal changes. This thinning can cause dryness, irritation, and dyspareunia (pain during intercourse). Reduced estrogen levels post-menopause also result in decreased glycogen deposition and alterations in the vaginal microbiome, with a decreased likelihood of lactobacilli dominance and increased diversity of anaerobic bacteria.
neovagina
Vaginoplasty, particularly penile inversion vaginoplasty, is the primary surgical technique for feminizing genital surgery. This procedure aims to create a neovagina with concordant vulvar anatomy, adequate depth, moisture, and sensation. Penile skin, often supplemented with scrotal skin grafts, is commonly used to line the neovagina.
The epithelium of penile skin differs from that of the pre-menopausal estrogen-dominated vagina (EDV) and sigmoid colon. Penile skin is thinner, expresses different cytokeratins, and lacks the glycogen-rich superficial layer found in the EDV. Instead, it has a soft-cornified outer layer, limiting water loss and providing mechanical integrity. This contrasts with the EDV’s epithelium, which supports lactobacilli colonization. The influence of surgical invagination and exogenous estrogen on neovaginal epithelial differentiation remains poorly understood. Neovaginas constructed from penile skin retain some degree of cornification and lack glycogen production, making lactobacilli colonization challenging.
Little is known about the neovaginal microbiome’s composition and its impact on health. Recent studies suggest that the microbiota in penile skin-lined neovaginas resembles that of uncircumcised penises, with Prevotella, Peptostreptococcus, and other anaerobes being prevalent. In contrast, neovaginas constructed from sigmoid colon tissue lack these anaerobes, instead harboring gut-associated bacteria like Bacteroidaceae and Enterobacteriaceae.
Krakowsky et al. (2022)
good for STI neisseria gonorrhoeae, Chlamydia trachomatis, and bacterial vaginosis. oestrogen lactobacillus and lowering pH.
Mention if talking about women taking testosterone and even penile inversion.
