Changes in the vaginal microbiota across a gradient of urbanizationOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study asked whether urbanization and ethnicity shape the vaginal microbiota of Indigenous Amazonian women. It compared cervicovaginal and introital microbiota across a gradient from remote villages to a town. Amerindian Piaroa women were individually classed as low, medium, or high urbanization based on lifestyle adoption. Urban mestizo women served as an ethnic comparison. Samples from two sites were profiled by 16S rRNA gene sequencing of the V1-V3 region. Human papillomavirus status was also assessed and related to microbiota.
Who was studied?
Participants were 111 sexually active women from the Venezuelan Amazonas state, including 82 Amerindian Piaroa women spanning urbanization and 29 urban mestizo women. Mean age was 28.9 years, ranging from 12 to 53. Women were sampled by a physician at introital and cervicovaginal sites, and yielded 196 analyzable samples after quality control. The cohort lived along a real urbanization gradient, from remote forest villages without running water or electricity to the town of Puerto Ayacucho.
What were the most important findings?
Lactobacillus iners-dominated and high-diversity profiles prevailed, with Lactobacillus iners being the dominant species in 45 percent of women. Cervicovaginal samples formed four community state types and introital samples formed two. Microbiota diversity showed only a weak, non-significant trend of increasing with urbanization among Amerindians. Ethnicity effects were minor once urbanization and location were fixed. Urban Amerindians were marked by an aerobic, cheese-associated bacterium and a taxon linked to persistent bacterial vaginosis, while mestizo women carried bacterial-vaginosis-associated high-diversity taxa. HPV status did not associate with diversity.
What are the greatest implications of this study?
The results suggest that among these Amazonian women, lifestyle urbanization and ethnicity have only a modest influence on the vaginal microbiota. Lactobacillus iners and diverse profiles associated with vaginal health outcomes dominated across groups. This pioneering work extends microbiome study beyond urban populations in wealthy countries. Sample sizes were small due to remote access, and genetic ethnicity data were unavailable, so genetic and lifestyle contributions could not be separated. Findings are associational and should be confirmed in larger, more diverse populations.