Microbial Diversity Of Human Breast Milk In Four Areas Of China

Nowadays, a lot of research show that breast milk also contains abundant microbes as well as other parts of the human body, and some of them were confirmed has potential beneficial effects such as immunological maturation of infant and infection protection of pregnant women. In the present study,60 breast milk samples were collected from 60 volunteers pregnant women distributed in four areas (Guang Xi autonomous region, Jiang Su province, He Bei province and Hei Long Jiang province).16 s rRNA V1-V3 variable region metagenome sequencing, q-PCR technology and analysis of bioinformatics were applied to investigate the structure and diversity of breast milk. At the phylum level, a total of 35 taxa were identified in samples. And within this content (accounted for 99.55%), the Proteobacteria (62.79%), Firmicutes (26.84%), Actinobacteria (5.96%) and Bacteroidetes (3.96%) were dominant in the total sequencing of sequence. At the genus level, a total of 608 taxa were identified, and the relative content of species which higher than 1.0% including Acinetobacter (20.26%), Pseudomonas (11.93%), Enterobacter (5.24%), Serratia (4.30%), Enhydrobacter (2.02%), Sphingomonas (1.71%), Klebsiela (2.83%), Ralstonia (1.25%), Stenotrophomonas (4.16%), Streptococcus (14.49%), Staphylococcus (9.29%), Bacillus (1.41%), Rothia (2.35%) and Corynebacterium (1.67%). The amounts of Enterobacter, Pseudomonas, Streptococcus, Staphylococcus, Lactobacillus and Bifidobacterium genera were 5.01±1.01,4.27±1.18,5.59±1.31,4.37±1.25,3.45±0.56 and 3.53±0.23 in log-transformed 16S rDNA gene copy number per milliliter of sample by using qPCR, respectively. The core microbiota based on geographical location showed that Acinetobacter, Enterobacter, Pseudomonas, Staphylococcus, Stenotrophomonas and Streptococcus were the core microbiota of the volunteers living in four different geographical areas. Furthermore, the core microbiota both in colostrum and mature milk including Klebsiella, Ralstonia, Chryseobacterium, Sphingomonas, Enhydrobacter, Stenotrophomonas, Serratia, Enterobacter, Pseudomonas, Streptococcus, Staphylococcus and Acinetobacter. Moreover, the correlation analysis showed there exist a significant negative correlation between Acinetobacter and other bacterial genus and a significant positive correlation between Chryseobacterium and Caulobacter. To analyze the alpha and beta diversity of the microbial community in breast milk samples based on geographic location, the mode of breast milk and delivery, and it showed that, the lactation women from different geographic location and different mode of delivery had different microbiota, but the difference was not significant. However, the microbial diversity between colostrum and mature milk had significant difference, and the different genera mainly including Enterobacter, Bifidobacterium, Staphylococcus, Propionibacterium, Arcobacter, Finegoldia, Agrobacterium, Brevundimonas, Ochrobactrum, Microbacterium and Sphingobacterium. Therefore, the types of breast milk is a principal factor that influence microbial diversity of breast milk.