Human Milk Microbiome of Healthy Indian Mothers is Dominated by Genus .

Background: The composition of the human milk microbiome is highly variable and multifactorial. Milk microbiota from various countries show striking differences. There is a paucity of data from healthy lactating Indian mothers.

Research Aim: To describe the milk microbiota of healthy North Indian women, using a culture-independent, targeted metagenomic approach.

Methods: We recruited exclusively breastfeeding mothers ( = 22) who had vaginally delivered full-term singleton infants in a tertiary care hospital less than 1 week previously and had not recently consumed systemic antibiotics. Milk samples (5 ml) were collected aseptically, and microbial deoxyribonucleic acid was extracted. Microbial composition and diversity were determined using a 454-pyrosequencing platform. Core genera were identified, and their relative abundances ranked. Heatmaps showing the variation of the ranked abundances and Shannon index were obtained using R.

Results: Participants (all exclusively vegetarian) had a mean () age of 27.2 (3.4) years, postnatal age of 3.9 (1.6) days and gestation 38 (1.2) weeks. The dominant phylum was Proteobacterium (relative abundance 84%) and dominant genus (relative abundance 61.78%). Eleven species of were identified, all generally considered nonpathogenic. Based on abundance patterns of the core genera, the milk samples could be grouped: (a) dominated by with low diversity; (b) less and high diversity; and (c) dominated by but high diversity. All neonates were healthy and gaining weight well at 1 month of age.

Conclusions: Healthy, lactating, vegetarian, North Indian women who deliver at term gestation and have no recent exposure to antibiotics, have a unique milk microbiome dominated by