High proportions of Lactobacillus are thought to be important to maintaining vaginal health. Lactobacillus species provide a key function through the production of lactic acid, which is thought to preclude colonization by pathogenic organisms. Four species — L. crispatus, L. iners, L. gasseri, and L. jensenii — typically dominate the communities of most reproductive age women. Communities with low proportions of lactobacilli are often associated with increased susceptibility to sexually transmitted infections (STIs), in addition to other adverse reproductive outcomes. Vaginal community composition differs between women and changes over time. Changes in community composition resulting in low proportions of lactobacilli expose women to windows of risk for STIs. Currently, the mechanisms driving changes in vaginal community composition are poorly understood.
Figure 1, depicts our current understanding of the factors that possibly determine the abundances of Lactobacillus in the vagina.The abundances of vaginal lactobacilli are often associated with estrogen levels and vaginal glycogen content. Thus, glycogen is thought to support vaginal colonization and proliferation of lactobacilli. However, studies have shown that vaginal lactobacilli cannot directly metabolize glycogen, and that α-amylase likely depolymerizes glycogen to form products that lactobacilli can metabolize. Consistent with this, amylase activity has been demonstrated in vaginal secretions. We expect the differences in community composition are due to variation in the kinds and amounts of resources available to the community, which could be influenced by estrogen and stress.
Figure 1. Scheme for the production and use of glycogen-derived resources by vaginal lactobacilli. Host estrogen stimulates the production and accumulation of glycogen, which is degraded by human α-amylase to produce simpler sugars that are consumed by vaginal lactobacilli and fermented to produce lactic acid.
Drivers of changes in vaginal bacterial community composition:
What is the role of estradiol and stress?
2003 - 2007
BS - Biology, Minor - Chemistry
Risks for sexually transmitted infections:
How can we translate our research into mitigating sexual and reproductive health risks in women?
Host - Environment - Bacterial community:
Multiple types of interactions occur within the vaginal ecosystem. How important are these interactions in determining the composition of vaginal communities?
2012 - 2014
University of North Carolina at Chapel Hill
MS - Biomedical Engineering
2014 - 2020
University of Idaho
PhD - Bioinformatics and Computational Biology
Human, bacterial, or both?