抗生素暴露对极早产儿出生后不同时间肠道菌群定植的影响

Effect of antibiotic exposure on intestinal flora colonization in very premature infants at different time points after birth

目的探讨基于16S核糖体RNA(16S rRNA)基因测序技术动态监测抗生素治疗的极早产儿(VPI)出生后不同时间肠道菌群的定植及演变过程。方法选取生后24 h内使用抗生素治疗的VPI(胎龄<32周)20例为研究对象,收集VPI的一般临床资料[性别、胎龄、出生体质量、分娩方式、胎盘/脐带/羊水情况、喂养方式、抗生素使用种类和持续时间、有无使用呼吸机和使用时间、住院时长,住院期间新生儿肺炎、脓毒症、新生儿呼吸窘迫综合征(RDS)、支气管肺发育不良(BPD)、新生儿颅内出血(IVH)及新生儿坏死性小肠结肠炎(NEC)的发生情况];收集VPI生后第1天(使用抗生素前,A0)、第3天(A1)、第1周(A2)、第1月(A3)及第3月(A4)的粪便标本,采用16S rRNA基因测序技术进行肠道菌群的生物信息学分析肠道菌群扩增子序列变异体(ASV)数目、Chao1指数、shannon指数、菌门和菌属变化特点及表型预测。结果VPI肠道菌群ASV数目、Chao1指数及shannon指数A1时开始下降,随着抗生素的停用及日龄的增加有所恢复;变形菌门相对丰度先增加后减少,厚壁菌门相对丰度先减少后增加,放线菌门在生后处于稳定的低丰度状态、A4时迅速增加;菌属演替依次为明串珠菌属及克雷伯菌属、双歧杆菌属;刚出生时最先定植的是需氧菌和兼性厌氧菌,A4时厌氧菌和兼性厌氧菌成为优势菌群。结论VPI生后抗生素暴露可能会降低肠道菌群的丰富度及多样性,生后3个月内肠道菌群组成结构、相对丰度及表型不断变化。

Objective To investigate the colonization and evolution of intestinal flora in very preterm infants(VPIs)treated with antibiotics at different time points based on 16S ribosomal RNA(16S rRNA)gene sequencing technology.Methods Twenty VPIs(gestational age<32 weeks)treated with antibiotics 24 h after birth were selected as the subjects.General clinical data of VPIs,(including gender,gestational age,birth weight,delivery mode,placenta/umbilical cord/amniotic fluid,feeding mode,antibiotic type and duration,ventilator use and time of ventilator use,length of hospital stay)were collected.Incidence of neonatal pneumonia,sepsis,neonatal respiratory distress syndrome(RDS),bronchopulmonary dysplasia(BPD),neonatal intracranial hemorrhage(IVH),and neonatal necrotizing enterocolitis(NEC)during hospitalization.Fecal specimens of VPI were collected from Day 1(A0 before antibiotics),Day 3(A1),Week 1(A2),Month 1(A3),and Month 3(A4)after birth.16S rRNA gene sequencing technology was used to analyze the number of amplicon sequence variants(ASV),Chao1 index,shannon index,flora and genus of intestinal flora,and to predict their phenotypes.Results The number of ASV of VPIs intestinal flora,Chao1 index and shannon index A1 began to decline,and recovered with the cessation of antibiotics and the increase of age.The relative abundance of Proteobacteria increased first and then decreased,Firmicutes decreased first and then increased,Actinobacteria remained in a stable state of low abundance after birth,and increased rapidly at A4.The sequence of bacterial genera was Leuconostoc,Klebsiella,and Bifidobacterium.Aerobes and facultative anaerobes were the first to colonize at birth,and they became the dominant bacterial groups at A4.Conclusions Postnatal antibiotic exposure to VPIs may reduce the richness and diversity of intestinal flora,and the compositional structure,relative abundance and phenotype of intestinal flora continue to change within 3 months postnatal.