Research On The Intestinal Flora Diversities And Compsition Of Dominant Bacteria Of Infants On Different Months In Shanxi Province

Intestinal flora is crucial for the development of infants and it's immune system construction.It is also closely linked to adult health and disease.Childhood(within 1000 days after birth)is a key period for colonization and establishment of intestinal flora.The colonization diversity of the intestinal flora at this stage influences the establishment of the infant's immune system and the health status in the future.This study collected the stool samples of healthy infants divided into 3 stages(group ?(0~6 months),group ?(6~12 months),and group ?(12~36 months)to analyze microbial diversity by high throughput 16 S r RNA,T-RFLP and QPCR technology.The purpose of this study was to explore the diversity of intestinal flora and the composition and diversity of dominant bacteria represented by Bifidobacterium and Lactobacillus of infants,which would provide a reference for revealing the relationship between intestinal microecology and health in early life,assessment of infant health and the development of infant formulae.The main conclusions were as follows:(1)The results of the intestinal microbiota diversity in the infants with different months by high throughput 16 S r RNA sequencing technology showed that:(1)In 36 infant samples,?,?,and ? groups showed differences at the level of the phylum,and the dominant bacteria at the level of phylum,class,order,family,and genus were same in the group ? and ? whose dominant genus was Bifidobacterium(56.32%,58.62%).In addition,there was no significant difference in the abundance of dominant bacteria at the corresponding classification level between the two groups(p>0.05).The predominant bacteria at the the level of genus were Bifidobacterium(25.09%)and Faecalibacterium(19.22%)in the group ?;(2)The bacterias whose abundance caused differences between the three groups were varied;(3)There was no significant differences in gut microbiota at the level of phylum between group ? and group ? with different genders and delivery methods(p>0.05),however,there were significant differences in the intestinal flora of group ?(vaginal delivery method)infants with different sex and those of group ?(female)infants with different delivery methods,and the different floras were all Bacteroidetes whose abundance in the girl group was significantly higher than that of the boy group and in the vaginal delivery group was significantly higher than that of the caesarean section group(p<0.05).(2)Using T-RFLP and QPCR techniques to evaluate the population diversity of Bifidobacterium showed that:(1)The result of T-RFLP showed that there were Bifidobacterium longum,Bifidobacterium breve,Bifidobacterium bifidum,Bifidobacterium animalis,and Bifidobacterium pseudocatenulatum in all groups,and there was also Bifidobacterium adolescentis in the group ?.However,the result of QPCR showed that there were 6 species in the three groups of samples;(2)The DNA content of Bifidobacterium in the?,?and ? groups were about 1010 copies/g,and the content of group ?(1010.44 copies/g)was significantly higher than that of group ? and ?(p<0.05);(3)The abundance of Bifidobacterium longum and Bifidobacterium breve in the samples of ? and ? groups were higher,and the corresponding abundance in the ? and ? group were 39.8 1%,30.90% and 35.48%,27.54% respectively.The top three abundance of species in the group ? were Bifidobacterium longum,Bifidobacterium breve and Bifidobacterium bifidum,which were 28.84%,27.54% and 34.67% respectively.(3)The results about the diversity of Lactobacillus of infants' samples determined by QPCR showed that:(1)Lactobacillus,Lactobacillus breve and Lactobacillus casei were detected in all of infants' samples.The number of same Lactobacillus species detected in the group ? samples was lower than that in the group ? and ?;(2)The contents of Lactobacillus in the three groups were all around 108.5 copies/g,and there was no significant difference between the three groups(p<0.05).The contents of both Lactobacillus reuteri and Lactobacillus casei were higher in the three groups;(3)The Lactobacillus casei and Lactobacillus reuteri were the most prevalent Lactobacillus species in the group ?,? and ?.The corresponding abundances in the group ? were 67.61%,and 27.54%,in the group ? were 48.98% and 43.65%,in the group ? were 33.88% and 56.23%.(4)There were significant differences in the diversity and distribution of intestinal microflora in infants aged 0~6 months,6~12 months and 12~36 months(p<0.05).The population composition of Bifidobacterium and Lactobacillus were not significantly different,however,there was a certain difference in abundance expression(p<0.05).