足月妊娠宫腔和宫腔周围内环境菌群的特征对比分析

The comparative analysis of microflora characteristics in uterine cavity and its surrounding environment in term delivery women

目的:探讨并对比分析足月妊娠宫腔及宫腔周围内环境菌群的特征。方法:选取2018年1月～2018年7月在北京大学深圳医院行足月剖宫产的26例孕妇。分别对孕妇宫颈管、盆腔、直肠、胎盘和羊水取样,提取总DNA,经16S rRNA V4区引物扩增、高通量测序及序列优化,通过生物信息分析比较不同部位菌群的特征。结果:(1)26例孕妇共收集114份样本,包括宫颈管、盆腔和胎盘样本各26份,羊水样本24例,直肠样本12例。所有样本经测序获得序列3019260条,经优化获得序列2544703条用于数据分析。(2)门分类水平上,宫颈管主要菌群为厚壁菌门(77.5%)和放线菌门(18.5%);盆腔主要菌群为变形菌门(65.7%)和厚壁菌门(16.4%);直肠主要菌群为厚壁菌门(52.1%)和拟杆菌门(39.1%);羊水主要菌群为变形菌门(67.5%)和厚壁菌门(12.3%);胎盘主要菌群为变形菌门(54.6%)和厚壁菌门(30.2%)。(3)属分类水平上,宫颈管主要菌群为乳杆菌属(75.9%)和加德纳菌属(14.8%);盆腔主要菌群为其他菌属(58.8%)和鞘氨醇单胞菌属(5.9%);直肠主要菌群为其他菌属(61.7%)和普氏菌属(28.9%);羊水主要菌群为其他菌属(54.0%)和窄食单胞菌属(7.6%);胎盘主要菌群为其他菌属(47.7%)和乳杆菌属(20.6%)。(4)宫颈管菌群的Shannon指数和OTU数均明显小于其他部位(P<0.05),羊水、胎盘及盆腔菌群的Shannon指数和OTU数两两对比无显著差异(P>0.05)。(5)主成分分析(PCA)能明显区分宫颈管菌群、直肠菌群,但未能显著区分羊水、盆腔和胎盘3个部位的菌群。结论:羊水和胎盘内有菌群定植,以变形菌门为主,其组成和多样性与盆腔菌群相近,与宫颈管和直肠菌群显著不同。

Objective: To investigate and compare the characteristics of microflora in uterine cavity and its surrounding environment in term delivery women. Methods: Samples from 26 pregnant women with full-term cesarean section from Jan.2018 to Jul.2018 in Peking University Shenzhen Hospital were selected to analyze the characteristics of microflora in cervical canal,pelvic cavity,placenta,amniotic fluid and rectum using the 16S rRNA gene amplicon sequencing. Results:(1)There were 114 samples collected from these 26 cases,including 26 samples from cervical canal,pelvic cavity and placenta respectively,24 samples of amniotic fluid and 12 samples from rectum.A total of 2544703 optimal sequences was extracted from 3019260 raw sequences.(2)On the phyla level,the predominant microfloras in cervical canal were Firmicute (77.5%) and Actinobacteria (18.5%).The predominant microfloras in pelvic cavity were Proteobacteria (65.7%) and Firmicute (16.4%).The predominant microfloras in rectum were Firmicute (52.1%) and Bacteroidete (39.1%).The predominant microfloras in amniotic fluid were Proteobacteria (67.5%) and Firmicute (12.3%).The predominant microfloras in placenta were Proteobacteria (54.6%) and Firmicute (30.2%).(3)On the genus level,the predominant microfloras in cervical canal were Lactobacillus (75.9%) and Gardnerella (14.8%).The predominant microfloras in pelvic cavity were other genus (58.8%) and Sphingomonas (5.9%).The predominant microfloras in rectum were other genus ( 61.7 %) and Prevotella (28.9%).The predominant microfloras in amniotic fluid were other genus (54.0%) and Stenotrophomonas (7.6%).The predominant microfloras in placenta were other genus (47.7%) and Lactobacillus (20.6%).(4)The shannon index and OTUs of the microbiome in the cervix canal were both significantly less than that in other sites ( P <0.05).The shannon index and OTUs had no significant differences between the pelvic cavity,placenta and amniotic fluid.(5)According to PCA analysis,the microfloras in cervical canal and rectum could be distinguished from that in amniotic fluid,pelvic cavity and placenta,while the microfloras in amniotic fluid,pelvic cavity and placenta could not be distinguished from each other. Conclusions: Microfloras can be detected in amniotic fluid and placenta,and the composition and diversity of microfloras in amniotic fluid and placenta are similar to that in pelvic cavity while different from that in cervical canal and rectum.