Microbial communities in the human vagina exhibit symbiotic relationships with the host and play critical roles in maintaining health and preventing disease. These roles include protection against colonization and disease by pathogens and regulation of local immune responses. Several different kinds of vaginal communities occur in reproductive age women and are associated with health; the majority of these community types are dominated by one of several Lactobacillus species (L. iners, L. crispatus, L. gasseri, and L. jensenii), each of which is believed to provide key ecosystem services. Lactic acid production is a particularly important trait of these species, one consequence of which is acidification of the vaginal habitat. Lactobacillus species and strains vary in their production of lactic acid, as well as in their associations with vaginal health- and disease-associated states. Other members of these Lactobacillus-dominated communities presumably play supporting and/or modulating roles in community-associated beneficial services. In contrast, a distinct set of vaginal communities is characterized by low-Lactobacillus abundance and high species diversity, including the presence of Gardnerella vaginalis and other strict and facultative anaerobic bacteria; these low-Lactobacillus, high diversity communities are sometimes associated with adverse health states, such as bacterial vaginosis, and increased risks of HIV acquisition, sexually-transmitted infections, vaginal candidiasis, and premature birth. These adverse states are believed to be associated with either overt or subclinical local inflammation, suggesting a potentially important role for host responses in these outcomes.
- Log in to post comments