Baby 2 Baby Beneficial Bacteria

The investigators will recruit mother-infant dyads to attend weekly lactation support groups and randomize infants to receive either an HMO consuming or non-HMO consuming probiotic. The investigators will collect infant stool before and after support group attendance. The investigators will use qPCR and metagenomic sequencing to test if the study probiotics or other bacteria transmit between infants. The investigators anticipate HMO consuming bacteria will and non-HMO consuming bacteria will not transmit between infants.

NOTE: Age limits listed are for mothers. For infants, age limits are a minimum of 1 day and a maximum of 1 monthInclusion Criteria:Healthy singleton pregnancy, term delivery (>= 36 weeks corrected gestational age)Maternal intent to exclusively breastfeed for the first six months of infant life (intent to breastfeed for six months correlates with longer duration of breastfeeding, this increases the chance that mothers will still be breastfeeding at the end of the study)Maternal vaccination against COVID19 (2 doses Pfizer or Moderna and within 6 months of second dose or 2 doses Pfizer or Moderna and booster.) COVID vaccination is required for maternal participation as this is a study meant to enable transmission of beneficial bacteria species between infants, and infants are too young to be vaccinated.Exclusion Criteria:Maternal drug abuseInfant congenital abnormalitiesInfant age greater than 1 month at first lactation support group meeting (younger infants will have less developed microbiomes, increasing the chance of successful transmission of bacteria)Intent to provide a non-study probiotics to the infantKnown immunocompromised status of the infant.