Human milk microbiome in urban and rural populations of India

Most of the studies examining human milk microbiota were focused on differences in bacterial taxa in relation to birthing method, gestation time and infant gender. In this study, we aimed to understand influence of different lifestyles on milk microbiota by utilizing metagenomic approach. Milk microbiota from 15 urban women living in metropolitan city and 15 rural women living in tribal village of Gujarat, India were profiled by 16S rRNA gene sequencing. The bacterial community in human milk contained over 26 phylum, 157 family and 543 different genera. Comparison of urban and rural milk microbiota revealed that they differ in both i) highly abundant taxa, including Proteobacteria (P = 0.008) and Firmicutes (P = 0.046), and ii) overall microbial diversity (Shannon index, P < 0.001). Despite of huge variation in microbial community structure, metabolic pathways were more stable and evenly distributed between urban and rural community. In concert, the study provided first insights into human milk microbial community of Indian population and demonstrated that different lifestyle can rapidly altered milk microbiota.