Skin microbiota variation in Indian families

AbstractBackgroundIn Indian culture, extended families have symbolized our tradition. Families often encompass members spanning multiple generations cohabiting the same household, thereby sharing ethnicity, genetics, dietary habits, lifestyles, and living conditions. The joint or extended family setup provides an opportunity to compare variations in microbiota composition within and between families. While previous research has demonstrated that skin microbiota can be influenced by factors such as ethnicity, geography, diet, age, and sex, its associations among Indian family members that may share also genetic background remains largely unexplored.MethodsThe present study involved seventy-two individuals from fifteen families in two geographical regions of Maharashtra, India. Bacterial DNA was extracted from axillary sweat samples, followed by sequencing of V3-V4 regions of the 16S rRNA. The generated taxonomic profiles were used to quantify microbiota diversity and similarities in skin microbiota composition within and between families, taking into account factors such as genetic relatedness, diet, sex, age, geographical location, and co-habitation.ResultsThe skin microbiota composition typically comprised Firmicutes, Proteobacteria, and Actinobacteria phyla. Notably, the Shannon alpha diversity was moderately associated with dietary habits and geographical location (Kruskal-Wallis; FDR<0.1), whereas no significant differences were observed for other key factors such as age, location, or sex. A significant association was also observed between taxonomic composition and shared familial membership (p=0.001; PERMANOVA), with a borderline significant association with geographical location (p=0.07). When within and between family comparisons were investigated across three generation (G1-G2, G2-G3 and G1-G3), no significant differences were observed, however, in general skin microbiota was more similar within than between families.ConclusionThis study underscores the diversity and commonalities in skin microbiota composition within and between families. We observed that every family has a unique skin microbiota and among the various covariates, significant association was observed for diet and geographical location. Our study highlights that family relations may have specific associations with skin microbiota composition and diversity. Further studies with larger sample sizes will help to elucidate the relative contributions of shared co-habitation and genetic backgrounds.