Cervicovaginal Microbiota and Reproductive Health: The Virtue of Simplicity

Abstract

Cervicovaginal microbiota play a critical role in women's health and reproductive outcomes. Despite being one of the simplest commensal bacterial communities in the human body, we are only beginning to appreciate its complex dynamic nature and important role in host immune modulation. In this review, we discuss the "optimal" cervicovaginal bacterial community composition, the impact of microbiota on gynecologic and obstetric outcomes, and the hurdles to developing a deeper mechanistic understanding of the function of the cervicovaginal microbiome. We then describe efforts to durably alter microbial composition in this compartment by promotion of Lactobacillus colonization with probiotics, modulation of vaginal pH, hormonal administration, and the eradication of pathogenic bacteria with antibiotics. Finally, we draw on lessons learned from the deeply investigated gut microbiome to suggest future avenues of research into host-pathogen interactions in the female genital tract.

Deciphering the effect of reproductive tract microbiota on human reproduction

“…The percentage of women with a lower genital tract dominated by Lactobacillus is 90%, 80%, 60%, and 60%‐37% in White, Asian, Hispanic, and Black populations, respectively . The variation of microbiota profiles in these populations may reflect not only racial or genetic predisposition to one or other types of bacteria, but also geographic, social, and/or economic factors . Among the endogenous factors known to contribute to microbiome changes are hormonal changes during the menstrual cycle.…”

“…The use of antibiotics has been widely studied to treat BV and prevent preterm birth (reviewed in []). But the usefulness of antibiotic use before embryo transfer remains controversial; while it is efficient in reducing upper genital tract contamination, no beneficial role has been observed in pregnancy outcome .…”

Changes in the vaginal microbiota associated with primary ovarian failure

“…In recent years, a wealth of evidence has been published supporting the significant contribution of cervicovaginal microbiota to genitourinary and reproductive health outcomes [27]. It was first found that the microbial taxonomic composition differs between women with POF and healthy individuals.…”

Lipschütz genital ulcer revisited: is juvenile gangrenous vasculitis of the scrotum the male counterpart?

“…These Döderlein bacilli or Bacillus crassus were later identified as Lactobacillus acidophilus species, with L. crispatus , L. gasseri , L. iners and L. jensenii as the dominant species in the vaginal microbiota . They are considered as normal microbiota in the cervicovaginal econiche . The possible involvement of Mycoplasma fermentans , a Gram‐negative commensal in human genital tract of controversial pathogenic significance, in Lipschütz genital ulcer has been suspected .…”

“…12 They are considered as normal microbiota in the cervicovaginal econiche. 13 The possible involvement of Mycoplasma fermentans, a Gram-negative commensal in human genital tract Figure 1 The first type of Lipsch€ utz genital ulcer (Abb. 1., Lip-sch€ utz B, 1927), the gangrenous form in his words, displayed limited numbers of isolated, well-defined, large deep-penetrating ulcers of overnight acute onset, mostly on the inner surface of labia minora, covered with adhering thick dirty grey-yellow to blue-black eschars, accompanied by striking burning painfulness, significant perilesional oedema and redness, regional lymphadenopathy, systemic fever and chills, which rapidly enlarged within the next 48 h. 3 of controversial pathogenic significance, 14 in Lipsch€ utz genital ulcer has been suspected.…”