Effect Of Prenatal And Postnatal Antibiotic Exposure On The Development Of Intestinal Microbiota Of Preterm Infants

Part Ⅰ: The Effect of the Intensity of Prenatal and Postnatal Antibiotic Exposure on the Development of Intestinal Microbiota of Preterm Neonates During the Early Stage by Using High Throughput Sequencing【Objective】 To analyze the effect of the intensity of prenatal and postnatal antibiotic exposure on the development of intestinal microbiota of preterm neonates during the early stage with the application of high throughput sequencing.【Method】 Hospitalized preterm infants who were exposed to prenatal and postnatal antibiotics and who were exposed to postnatal antibiotics were enrolled and divided into two groups according to the time they were exposed to antibiotics: >7 day group,≤7 day group.The fecal samples on d14 were collected.The DNA of bacteria in the fecal samples was studied with high throughput sequencing,the results of which were analyzed by bioinformatics methods.【Results】 A total of 22 bacterial DNA samples from 22 cases of preterm infants on d14 were analyzed.(1)The Shannon index did not differ significantly between the two groups on d14.(2)The intestinal microflora structure was simple and the Firmicutes and Proteobacteria were dominant.(3)On d14,the microbiota structure was similar between the two groups;in the >7 day group Klebsiella and Enterococcus increased,while Shigella and Streptococcus decreased.However,Bifidobacterium decreased significantly(p<0.05).【Conclusion】The increased exposure to antibiotics can change the intestinal microflora structure and lead to the increase of conditioned pathogen like Klebsiella and Enterococcus.However,Bifidobacterium,which is protective probiotics,decreased significantly.PartⅡ: The Effect of Prenatal Antibiotic Exposure on the Development of Intestinal Microbiota of Preterm Neonates During the Early Stage by Using High Throughput Sequencing【Objective】To investigate the effect of prenatal antibiotic exposure on the development of intestinal microbiota of preterm neonates during the early stage with the application of high throughput sequencing.【Method】 Two groups were divided: the experimental group was exposed to prenatal and postnatal antibiotics,while the control group was exposed to postnatal antibiotics without prenatal antibiotic exposure on the part of the pregnant mother.The fecal samples on d7 and d14 were collected.The DNA of bacteria in the fecal samples was studies with high throughput sequencing,the results of which were analyzed by bioinformatics methods.【Results】A total of 24 bacterial DNA samples from 24 cases of preterm infants were analyzed.(1)The Shannon index did not differ significantly between the two groups on d7 and d14.(2)The Intestinal microflora structure was simple and the Firmicutes and Proteobacteria were dominant.(3)In the group exposed to prenatal antibiotics,the colonization of Bifidobacterium was delayed.On d7,there was no colonization of Bifidobacterium On d14,the cases of Bifidobacterium appearance were obviously fewer than those in the control group.【Conclusion】The prenatal antibiotic exposure can change the Intestinal microflora structure of preterm infant and lead to the delay of the colonization of Bifidobacterium.Part Ⅲ: The Effect of Prenatal and Postnatal Antibiotic Exposure on the Development of Intestinal Microbiota of Preterm Neonates with Different Delivery Modes During the Early Stage by Using High Throughput Sequencing【Objective】 To study the effect of prenatal and postnatal antibiotic exposure on the development of intestinal microbiota of preterm neonates with different delivery modes during the early stage with the application of high throughput sequencing.【Method】 Hospitalized preterm infants who were exposed to prenatal and postnatal antibiotics were enrolled and divided into two groups according to the different delivery modes: the vaginal delivery(VD)group,and the cesarean delivery(CD)group.The fecal samples on d7 were collected.The DNA of bacteria in the fecal samples was studied with high throughput sequencing,the results of which were analyzed by bioinformatics methods.【Results】 A total of 22 bacterial DNA samples from 22 cases of preterm infants were analyzed.(1)The Shannon index did not differ significantly between the two groups on d7.(2)The Intestinal microflora structure was simple and the Firmicutes and Proteobacteria were dominant.(3)On d7,the microbiota structure was similar between the two groups;there was no statistical difference between the two groups in terms of Klebsiella,Enterococcus,Shigella,Streptococcus and Bifidobacterium.【Conclusion】The antibiotics can change the Intestinal microflora structure,and lead to the change of inherent Intestinal microflora structure and difference between vaginal delivery and cesarean delivery.