Comparative 16S rRNA Sequencing of Human and Dairy Animal Milk Microbiota in Northern Greece

Milk constitutes a tissue with a dynamic composition of micronutrients and bioactive molecules which serves as a stable and customized nutrient source for infants. Milk composition is affected by a multiple of factors including genetics, geographical location and environmental conditions, lactation phase, and maternal nutritional status. In addition, milk's composition also plays a key role in dictating its microbiome, thus making it unique for each individual. One aspect that's been less explored is the comparison of microbial communities in human breast milk with those present in milk from other animal species. This study seeks to address this issue by utilizing 16S rRNA metagenomic sequencing to explore and contrast the complex microbial landscapes of human, bovine, and goat raw milk samples. Furthermore, prominent differences were observed between colostrum and mature milk, in line with the expected microbial richness vital for infant support. Alpha diversity analysis indicates moderate diversity and stability in bovine milk, high richness in goat milk, and constrained diversity in breast milk. Beta diversity reveals significant distinctions among mammalian species, emphasizing both presence/absence and abundance-based clustering. Despite noticeable differences, shared microbial components underscore fundamental aspects across all mammalian species, highlighting the presence of a core microbiome predominantly comprised of the Proteobacteria, Firmicutes, and Actinobacteriota phyla. At the genus level, Gemella and Jeotgalicoccus exhibit significant abundance in human milk compared to bovine and goat milk, while Pseudomonas is prevalent in animal milk. In conclusion, our analysis revealed differences and commonalities in the microbial communities of various mammalian milks and unraveled the existence of a common fundamental milk core microbiome. The findings underscore the complexity introduced by diverse dietary patterns and lifestyles among human populations, offering valuable insights for optimizing the nutritional quality and safety of dairy products and supplements for infant health. Tsifintaris M, Sitmalidis M, Tokamani M, Anastasiadi C, Georganta M, Tsochantaridis I, Vlachakis D, Tsikouras P, Nikolettos N, Chrousos GP, et al. Analysis of Human Milk Microbiota in Northern Greece by Comparative 16S rRNA Sequencing vs. Local Dairy Animals. Nutrients. 2024; 16(14):2175. https://doi.org/10.3390/nu16142175