Human Milk Microbiota: Origin and Potential Uses

Area of Science:

• Microbiology
• Human Health
• Lactation Biology

Background:

• Pioneering studies in the 21st century revealed a site-specific human milk microbiota.
• Human milk microbiota comprises Staphylococcus, Streptococcus, lactic acid bacteria, and other gram-positive bacteria, with DNA from anaerobic bacteria also detected.
• The precise origin of human milk bacteria remains largely unknown, with potential sources including the infant's oral cavity, maternal skin, and maternal digestive tract via enteromammary pathways.

Purpose of the Study:

• To explore the composition and origin of the human milk microbiota.
• To investigate the potential applications of the human milk microbiota for infant and maternal health.

Main Methods:

• Analysis of hygienically collected human milk samples from healthy women.
• Detection of bacterial DNA, including from strict anaerobic bacteria.
• Review of potential microbial sources and transmission routes.

Main Results:

• Human milk harbors a low bacterial load, predominantly gram-positive bacteria.
• Potential microbial sources include maternal skin, infant oral cavity, and maternal digestive system.
• External factors like unhygienic breast pump use can introduce contaminants.
• Human milk bacteria show potential for infant health (including preterm infants) and maternal health, particularly in preventing/treating infectious mastitis.

Conclusions:

• The human milk microbiota is a complex ecosystem with diverse bacterial species.
• Further research is needed to fully elucidate the origins and transmission routes of these microbes.
• Human milk bacteria hold significant promise for therapeutic interventions in both infants and mothers, especially for infectious mastitis.