New paper today in @cellhostmicrobe!

1/ #Breastmilk feeding practices associated w/ co-occurrence of #microbiota in mothers’ milk & infant gut

TEAMwork w/ @TurveyLab @FinlayLab @CHILDStudy + trainees Kelsey Fehr @ShirinMoossavi @rozzy_tb @sbihi_hind

https://www.cell.com/cell-host-microbe/fulltext/S1931-3128(20)30350-4

2/ In the @CHILDStudy, infant gut #microbiome composition was associated with #breastfeeding exclusivity and duration, but not feeding mode (pumping vs. nursing at the breast)

3/ Bacteria in breastmilk vs. infant gut were very different (of course!)

4/ … but, a few types of bacteria were commonly shared (and often correlated) between a mother’s milk & her infant’s gut:

5/ Notably, sharing of bacteria (ASVs) was more frequent between a mother’s milk & her OWN infant’s gut (actual pairs) than in random mother-infant pairs

So, it’s not that all moms/babies generally have similar bacteria – rather, moms share specific bugs w their own babies!

6/ How important are these shared bacteria to the infant gut #microbiome?

For context, we checked other well-known modifiers of the infant microbiome (at 3 mos), and the estimated effect of milk bacteria was similar to method of birth (vaginal vs. c-section) or having siblings.

7/ Interestingly, more bacteria were shared when infants were nursed directly at the breast.

8/ Why? We don’t know yet, but it could be that…
- Pumping & storing #breastmilk affects bacteria (fewer of mom’s microbes shared with baby)
- Nursing allows infant oral bacteria to inoculate milk (fewer of baby’s microbes shared with mom)

9/ Overall, our study provides evidence that (regardless of their source) specific bacteria may be transferred from a mother’s milk to her infant’s gut & influence microbiota development to a similar extent as other key early-life exposures.

10/ Of course, there is still lots to learn! (See: https://www.tandfonline.com/doi/full/10.1080/19490976.2019.1667722)

11/ Open questions:
- Where do milk bacteria come from? (Maternal gut? Infant mouth? Environment?)
- Regardless of their source, these bacteria appear to survive the trip to the infant gut… does this make them good #probiotic candidates?

12/ More questions…
- Implications for (pasteurized) donor milk?
- Why/how does pumping affect milk bacteria? How can we optimize this process for moms who pump?
- (How) do these milk & gut microbes influence infant health? What about the infant oral/nasal microbiomes?

13/ …Stay tuned to @CHILDStudy (& @smreyesphd) for answers!

14/ Big thanks to collaborators ( @Dr_LarsBode @EhsanKhafipour) + funders @CIHR_ISRC @AllerGen @Research_MB @canlung @InnovationCA!

… and to all the @CHILDStudy kiddos like Eloise who donated their diapers for science! (Check out the #CHILDStudyPosterContest for more artwork!)

15/ For a fun summary of this and other @CHILDSTUDY milk & microbiome research, check out our videos:
https://childstudy.ca/portfolio/child-study-videos/