Impact Of Postnatal Antibiotics On The Preterm Intestinal Microbiome And The Late Diseases

Objectives To assess the impact of postnatal antibiotics on the preterm intestinal microbiome by 16 Sr DNA sequencing technology,and analyze the influence of prophylactic antibiotics on the preterm late diseases.Methods Part 1 This study was conducted on 19 preterm infants admitted to NICU immediately after birth from September 2015 to February 2016.38 Fecal samples were collected to extract the DNA and amplify the 16 Sr DNA V4 region.The high-throughout sequencer Hiseq 2500 was used for faeces samples sequencing.From the latter,the bacterial composition,species abundance and community comparison were obtained.They were divided into 10 cases of short period antibiotic group(< 3 days)and 9 cases of long term antibiotic group(> 7 days).Part 2 A retrospective analysis was conducted on the preterm infants with a gestational age less than 34 weeks from October 2016 to November 2017.Their clinical data of antibiotic application and the incidence of LOS,feeding intolerance,NEC,pneumonia,BPD were sorted out.The intergroup difference was statistically analyzed by independent sample t test and chi-square test.Results Part 1 ⑴ There was no statistically significant difference of general data between the short term antibiotic group and the long-term antibiotic group.⑵The intestinal flora of the two groups were mainly composed of Lactococcus,Enterococcus and Bacillus before antibiotic use.After use of antibiotics,the proportion of Bacillus and Lactococcus decreased and Enterococcus increased.Besides,the ratios of Staphylococcus,Clostridium and Bifidobacterium also raised.⑶After the application of antibiotics,the four Alpha diversity indexes of the two group were statistically significant decreased,indicating that intestinal flora abundance was declined.⑷Beta diversity analysis found the two groups were more concentrated before use of antibiotics.The aggregation was lower after antibiotic application in the two groups.⑸Anoism analysis showed that there were statistically significant differences in intestinal flora for both the two groups before and after use of antibiotics,but there was no statistically difference between the two groups after antibiotic application.Part 2 From October 2016 to November 2017,there were 105 cases with prophylactic antibiotic application,143 cases without prophylactic antibiotics.The difference of delivery mode and gestational age and length of hospitalization between the two groups were of no statistically significance and the difference in birth weight was the opposite.The incidence of late clinical sepsis,septicemia,feeding intolerance,NEC and hospital acquired pneumonia(HAP)between the two groups were not significant while the difference of the incidence of BPD was the opposite.Conclusions The preterm antibiotic application,even if it is of short-term(<3days),may change the distribution of intestinal flora a lot.The outcome may be exacerbated by prolonged antibiotic use.Prophylactic antibiotics cannot reduce the incidence of LOS,feeding intolerance,HAP,and NEC.We are suggesting that the application of prophylactic antibiotics should be very rigorous,particularly early after birth.