Breastfeeding premature infants affects the microbiota composition of breast milk

To determine whether and how breast feeding of premature infants influences the human milk (HM) bacterial communities.

HM samples before and after breastfeeding were collected from 40 preterm infant mothers at 24-36^6/7 weeks of gestational age in the neonatal intensive care unit of our hospital. Of these 40 babies, 11 at 24-27^6/7 weeks of gestational age and 12 at 28-31^6/7 weeks were grouped into an extremely premature (EPM) group and a very premature (VPM) group, respectively. In addition, 11 with a birth weight (BWT) of 1000 g ≤ BWT < 1500 g were classified as a very low birth weight (VLBW) group and 12 with BWT < 1000 g an extremely low birth weight (ELBW) group. Breast feeding and kangaroo mother care were given once a day for 7 days, from 14 to 21 days of age. The bacterial composition of HM was analyzed using high-throughput sequencing before and after feeding.

Linear discriminant analysis effect size of HM samples before and after feeding showed that Bacillus, Prevotella and Fusobacterium were significantly enriched in HM before breastfeeding (P < 0.05). Post-feeding HM for the EPM group showed significant enrichment in Lactobacillales, Streptococcus, Desulfuromonadales, Ruminococcus, Geobacteraceae, Geobacter and Elizabethkingia_meningoseptica (P < 0.05). Bacillus was significantly enriched in the HM for EPM group before feeding (P < 0.05). For mothers with VLBW infants, Bacillus was enriched before feeding, while Lactobacillales was predominant after feeding (P < 0.05). There was a moderate correlation between the diversity of HM bacteria and infant development and immune outcomes.

Breastfeeding of preterm infants can significantly affect the bacterial diversity in HM.