The human microbiota is composed of a vast number of microorganisms inhabiting different body sites, especially the skin, gut, vagina. For women, the bacteria inhabiting the vaginal tract, specifically Lactobacillus spp. (mainly by L. crispatus, L. iners, L. jensenii, L. gasseri) play a key role in sexual and reproductive health. For instance, a disruption of the vaginal microbiota is associated with a variety of pathogenic disorders, such as bacterial vaginosis (BV), highly prevalent in Peru (estimated to range between 10-37%). Affected women are at increased risk of acquiring more serious infectious agents such as HIV, Chlamydia, Trichomonas, Neisseria. Other complications of BV include preterm premature rupture of membranes and neonatal sepsis.
Previously, a healthy vaginal microbiota composition has been defined when high numbers of lactic acid producing lactobacilli were present based on microscopy or culture-based approaches, including pH measurements. Nowadays with the development of culture-independent approaches such as next-generation sequencing (NGS), we know that the vaginal microbiota is not only composed of Lactobacillus species but also of a diverse group of strictly anaerobic bacteria. However, while several of these anaerobic bacteria appear to be associated to disorders such as BV, some might also be linked to health. This is at present not well understood.
Based on studies on the gut microbiota, several factors have been described that can influence this microbiota composition, including dietary habits, health status, demographics, environmental factors, and ethnicity. For the vaginal microbiota, this area of research is still largely underexplored.
Several studies indicate that ethnicity might also play a key role in shaping the vaginal microbiota. For example, Ravel et al. have observed that African American and Hispanic women have predominantly anaerobic bacteria compared to women from European ancestry (Lactobacillus-dominant). However, most vaginal microbiota studies have been focused on the "Western white woman" so far. Hence, the impact of ethnicity on the vaginal microbiota remains a critical research gap in this field.
To overcome various knowledge gaps on the vaginal microbiota, our research group has recently set up a citizen science project named Isala to explore the female microbiota's stability and temporal dynamics in relation to different lifestyle factors and environmental conditions. We also explore the importance of various individual and social risk factors that can influence the "healthy" vaginal microbiota. While we were aiming to recruit 200 volunteers in Flanders at the start of the project in March 2020, we managed to enroll at least 5528 women due to immense success and large amounts of subscriptions (we even had to stop registrations). This massive response from women highlights the need that it is important to understand the vaginal microbiota better, how this microbiota is influenced, and its impact on health.
In this present project proposal, we aim to implement the Isala project in Peru to radically increase our insights on the diversity of a "healthy" vaginal microbiota composition and the influence of ethnicity and other possible factors.