Breastmilk feeding practices are associated with the co-occurrence of bacteria in mothers’ milk and the infant gut: the CHILD Cohort Study


Gut microbiota play a critical role in infant health. It is now accepted that breastmilk contains live bacteria from endogenous and exogenous sources, but it remains unclear if these bacteria transfer to the infant gut and whether this process is influenced by breastmilk feeding practices. Here we show that certain bacteria including Streptococcus spp. and Veillonella dispar co-occur in mothers’ milk and their infants’ stool, and co-occurrence is reduced when infants receive pumped breastmilk. The relative abundances of commonly shared species are positively correlated between breastmilk and stool. Overall gut microbiota composition is strongly associated with breastfeeding exclusivity and duration, but not breastmilk feeding mode (nursing vs. pumping). Moreover, breastmilk bacteria contributed to overall gut microbiota variation to a similar extent as other modifiers of the infant microbiome, such as birth mode. These results provide evidence that breastmilk may transfer bacteria to the infant gut and influence microbiota development.

A great collaboration within CHILD Cohort Study between Meghan Azad’s group at University of Manitoba and Sturat Turvey’s and Bret Finlay’s groups at the University of British Columbia. The project was led by Kelsey Fehr, Hind Sbihi, Rozlyn C.T. Boutin, and me. Special congratulation to my talented mentee, Kelsey.

Press release by University of Manitoba and University of British Columbia here and here.

Cell Host Microbe Preview: Differding MK, Mueller NT. Human Milk Bacteria: Seeding the Infant Gut? Cell Host Microbe 2020; 28: 151-153.

Selected for cover art.

Cell Host Microbe
Shirin Moossavi
Shirin Moossavi
Postdoctoral Fellow
Meghan Azad
Associate Professor