[Breast milk microbiota of mothers with different glucose tolerance at 42 days postpartum]

To compare the differences in microbial community between lactating mothers with gestational diabetes mellitus(GDM) and normal glucose tolerance lactating mothers(control) at 42 days postpartum, and to explore the effect of GDM on the microbial composition and structure of breast milk.

A total of 21 mothers with GDM and 25 healthy mothers in Fuqing Maternity and Child Health Care Hospital at 42 days postpartum from May 2019 to September 2020 were enrolled. A questionnaire was used to collect the basic information and dietary intakes of mothers. The mother's milk was collected by using a sterile electric breast pump. Breast milk microbiota profiles were assessed by 16 S rDNA gene amplicon based sequencing of the V3-V4 region and the sequencing platform was Illumina Miseq PE3000, bioinformatics analysis was performed on the sequencing result.

Compared with the control group, the mothers in the GDM group consumed more vegetables(222.7(190.6, 333.1)g/d vs.176.4(49.5, 247.0)g/d, P=0.042). There was no significant difference in Alpha diversity between the two groups(P>0.05). Beta diversity analysis showed that there were significant differences in the microbial composition between the two groups(P<0.01). Breast milk microbiota species difference analysis showed that there were differences in several species between GDM group and NGT group at the levels from phylum to genus. Compared with control group, the relative abundance of Bacteroidota and Cyanobacteria in GDM group decreased significantly [(3.41±2.59)% vs. (1.23±0.82)%, (1.08±3.02)% vs. (0.10±0.11)%, P<0.05]. In the GDM group, Ralstonia, Rhodococcus, Burkholderia-Caballeronia-Paraburkholderia, Acinetobacter and Fluviicola were decreased((38.93±28.85)% vs. (26.70±28.37)%, (9.23±6.87)% vs. (4.88±6.03)%, (7.66±4.80)% vs. (2.77±1.33)%, (6.18±11.90)% vs. (2.76±6.10)%, (1.21±1.31)% vs. (0.33±0.62)%, P<0.05). The unclassified＿f＿＿xanthobacteraceae was increased, and the difference was statistically significant((0.85±3.15)% vs. (23.64±23.63)%, P<0.05).

There are differences in breast milk microbial community structure in women with different glucose tolerance at 42 days postpartum, Ralstonia, Rhodococcus, Burkholderia-Caballeronia-Paraburkholderia, Acinetobacter and Fluviicola were significantly lower comparing to the normal glucose tolerance mothers.