不同分娩方式对晚期早产儿肠道菌群的影响

目的 探讨不同分娩方式对晚期早产儿肠道菌群定植的影响。方法 以胎龄(周)为34~(0/7)～36~(6/7)的15例晚期早产儿为研究对象,根据分娩方式分为自然分娩组(n=8)和剖宫产组(n=7)。收集早产儿出生后3 d、7 d、14 d的粪便标本,应用高通量测序技术对细菌16S rRNA可变区中的V4区进行测序,分析肠道菌群多样性及组成结构。结果 (1)自然分娩组晚期早产儿粪便标本菌群多样性指数逐渐上升,剖宫产组的多样性指数较平稳,两组相比差异无统计学意义;(2)45份粪便标本中共检测出10个菌门,均以变形菌门、厚壁菌门、放线菌门和拟杆菌门为优势菌门,两组晚期早产儿生后变形菌门、拟杆菌门所占比例逐渐降低,厚壁菌门、放线菌门呈增多趋势。两组相比,剖宫产组7 d、14 d时拟杆菌门的相对丰度显著低于自然分娩组(Z=-2.896,P=0.004;Z=-2.120,P=0.040),变形菌门相对丰度仅在7 d时显著高于自然分娩组(Z=-2.190,P=0.030);(3)两组研究对象中,除自然分娩组14 d时以双歧杆菌属为优势菌属外,余下均以肠杆菌属为优势菌属。相比于自然分娩组,在7 d时剖宫产组拟杆菌属所占比例显著降低(Z=-2.806,P=0.005),肠杆菌属所占比例显著升高(Z=-2.199,P=0.030)。结论 剖宫产能显著影响婴儿早期肠道菌群的定植,降低肠道中早期拟杆菌的水平。

Impact of delivery mode on gut microbiota in late preterm infants

Abstract: Objective To explore the effect of delivery mode on the gut microbiota of preterm infants. Methods Fifteen hospitalized late preterm infants were enrolled and divided into two groups according to the mode of delivery, 8 cases in vaginal delivery group and 7 cases in caesarean section group). Fecal samples were collected at Days 3, 7 and 14 after birth, respectively to extract bacterial DNA. The microbial community diversity and composition was analyzed through sequencing V4 region of 16S rRNA with Illumina high-throughput sequencing technology. Results (1) The Simpson index in vaginal delivery group increased with the age, while that in caesarean delivery group was relatively stable. There was no significant difference between the two groups. (2) Ten phyla were detected from 45 samples. Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes were the most dominant in all samples. With the increasing of the age, the proportions of Proteobacteria and Bacteroidetes gradually decreased, while Firmicutes and Actinobacteria showed an increasing trend in both groups. Compared with the vaginal delivery group, the relative abundance of Bacteroidetes in caesarean delivery group at Days 7 and 14 showed significant reduction; At Day 7, the proportion of Proteobacteria was statistically higher than in vaginal delivery group. (3) Enterobacter sp. was dominant in both groups at the three time points except at Day 14 in vaginal delivery group where Bifidobacteria was dominant. At Day 7, the abundance of Bacteroidetes sp. was significantly lower, while that of Enterobacter sp. increased significantly in caesarean delivery group. Conclusion Cesarean section will affect the normal colonization of gut microbiota of preterm infants and is associated with the decrease of Bacteroidetes.