分娩方式对新生儿后期肠道菌群的影响

Influence of mode of delivery on post-neonatal gut microbiota

目的利用聚合酶链反应一变性梯度凝胶电泳法（polymerase chain reactiondenaturing gradient gel electrophoresis, PCR-DGGE）分析分娩方式对新生儿后期肠道菌群的影响。方法收集2013年4月至8月在南京市区出生的健康足月新生儿30例为研究对象，根据喂养方式分为纯母乳喂养组15例（包括剖宫产出生的新生儿7例和阴道分娩出生的新生儿8例）和混合喂养组15例（包括剖宫产出生的新生儿8例和阴道分娩出生的新生儿7例）。采集生后28d的粪便标本，抽提样本中细菌基因组总DNA，并对其16S rDNA V3可变区进行PCR扩增和DGGE电泳，获得肠道菌群指纹图谱，进行多样性和相似性特征分析。采用两独立样本t检验或矿检验进行统计学分析。结果（1）多样性分析发现，纯母乳喂养组中，剖宫产出生的新生儿肠道菌群条带数、多样性指数低于阴道分娩出生的新生儿（分别为9．71±4．27与15．12±4．19，2．13±0．39与2．61±0．32，P值均〈0．05），优势度指数高于阴道分娩出生的新生儿（0．13±0．04与0．08±0．03，P〈0．05），均匀度指数差异无统计学意义（P〉0．05）。混合喂养组中，剖宫产儿肠道菌群条带数和多样性指数低于阴道分娩出生的新生儿（10．88±3．23与16．29±5．38、2．26±0．37与2．66±0．31，P值均〈0．05），优势度指数平均值虽高于阴道分娩出生的新生儿，但差异无统计学意义（P〉0．05）；而均匀度指数差异亦无统计学意义（P〉0．05）。（2）相似性分析发现，大部分相同分娩方式新生儿的肠道菌群汇聚在一起，提示同一分娩方式新生儿的肠道菌群结构更为相似。结论在新生儿后期，剖宫产出生的新生儿的肠道菌群总体的种类及数量落后于阴道分娩出生的新生儿；剖宫产出生的新生儿肠道优势菌地位更突出，而阴道分娩出生的新生儿肠道菌种分布更均匀。

Objective To analyze the influence of mode of delivery on post-neonatal gut microbiota using polymerase chain reaction-denaturing gradient gel electrophoresis （PCR-DGGE） technology. Methods From April to August in 2013, thirty healthy urban full-term neonates in Nanjing City were enrolled in the study, including fifteen exclusive breastfed ones （seven born of caesarean section and eight born vaginally） and fifteen mixed feeding ones （eight born of cesarean section and seven born vaginally）. Stool specimens were collected on the 28th day after birth and bacterial genomic DNA was extracted and examined by PCR on 16S rDNA V3 variable region. Bacterial community profiles were obtained by DGGE. Diversity and similarity differences of the gut microbial community structures were analyzed. Two independent sample t test or Chi-square tests were used for stastistical analysis. Results （l）Diversity analysis showed that among exclusive breastfeeding infants, the Strip number and Shannon-Weaver Diversity Index of gut microbiota in infants born abdominally were significantly lower than those born vaginally [9.71 ±4.27 vs 15.12±4.19, 2.13±0.39 vs 2.61±0.32, both P〈0.05], but the Simpson index of gut microbiota was significantly higher [0.13 ± 0.04 vs 0.08±0.03, P〈0.05], and no significant difference was shown in Pielou Index （P〉0.05）. In the mixed feeding group, the Strip number and Shannon-Weaver Diversity Index of gut microbiota in infants born abdominally were significantly lower than those born vaginally [10.88±3.23 vs 16.29±5.38, 2.26±0.37 vs 2.66±0.31, both P〈0.05], the Simpson index was higher, but together with the Pielou Index, neither showed significant difference （both P〉0.05）. （2） Similarity analysis found that gut microbiota from neonates born of same mode of delivery mostly gathered together and had much more similar structures. Conclusions In the post-neonatal period, the species and numbers of gut microbiota in infants born abdominally are all behind of those born vaginally. The predominant microbiota in babies born of cesarean section are more prominent, and gut microbiota in vaginal delivered babies are more uniformly distributed.