正常孕妇阴道菌群特征及影响因素

Vaginal microbiota characteristics and influencing factors in normal pregnant women

目的:研究正常孕妇阴道菌群特征及影响因素。方法:本研究基于2018年2月至2020年2月在安徽医科大学附属安庆医院建立的孕妇队列,将所有符合纳入排除标准的"正常"孕妇阴道样本,按采样孕周顺序排列,以每个孕周为一抽样层,每层随机抽取5例样本,不足5例则全部纳入,使用16S rRNA基因测序技术测得样本V3~V4序列。利用MicrobiomeAnalyst进行优势菌种分析。Alpha多样性以Chao1、Observed Features、Shannon、Simpson、Faith_pd、Pielou′s Evenness指数的对数值进行表示,并依据样本是否以乳酸菌为主导划分为两类,分别利用多重线性回归、Logistic回归探索影响因素。连续性变量采用方差分析、Kruskal Wallis检验,分类数据则采用卡方检验、Fisher检验。P<0.05时认为数据差异有统计学意义。结果:本研究纳入91例孕妇/91例阴道标本,平均年龄为(27.37±3.60)岁,孕早期、孕中期、孕晚期分别纳入18个、56个和17个阴道样本,孕周中位数分别为11.93周、19.43周和38.29周。样本物种组成:门水平上,厚壁菌门相对丰度为91.30%;属水平上,乳酸菌属相对丰度为87.67%;种水平上,惰性乳酸菌、卷曲乳酸菌相对丰度分别为42.95%、36.33%。惰性乳酸菌在所有孕期均显示出优势性,其相对丰度较高的样本数随孕期逐渐减少,卷曲乳酸菌在孕中期、孕晚期显示出优势性,其相对丰度较高的样本数随孕期逐渐增加。孕期阴道菌群Alpha多样性随着孕周推进,呈逐渐降低的趋势。不同吸烟习惯孕妇阴道菌群Pielou′s Evenness多样性指标差异有统计学意义(P<0.05),不同饮酒习惯孕妇阴道菌群Shannon多样性指标差异具有统计学意义(P<0.05)。不同教育水平孕妇阴道菌群Chao1、Observed Features、Faith_pd多样性指标差异有统计学意义(P<0.05),不同收入水平孕妇阴道菌群Shannon、Simpson多样性指标差异有统计学意义(P<0.05)。结论:正常孕妇阴道内以乳酸菌为主导,随着孕期推进,惰性乳酸菌的优势性逐渐降低,卷曲乳酸菌优势性逐渐升高。正常孕妇阴道菌群Alpha多样性与吸烟、饮酒、教育水平、家庭收入水平有关,孕前戒烟、孕前有饮酒习惯的孕妇阴道菌群Alpha多样性较低,较低教育水平、较高家庭收入水平孕妇阴道菌群Alpha多样性较高。

Objective To study the characteristics and influencing factors of vaginal microbiota in normal pregnant women.Methods This study was based on a cohort of pregnant women established in Anqing Municipal Hospital Affiliated to Anhui Medical University from February 2018 to February 2020.Vaginal samples of normal pregnant women who met the inclusion and exclusion criteria were ordered by the gestational weeks at sampling.Five samples were randomly selected from each gestational week group and if the samples were less than five,all samples were included.Sequencing of the V3-V4 region of the 16S rRNA gene was performed.Dominant species were analyzed by MicrobiomeAnalyst.Alpha diversity was measured with Chao1,Observed Features,Shannon diversity,Simpson diversity,Faith_pd and Pielou′s Evenness.The dominant status of Lactobacillus was also described and compared.Multiple linear regression and logistic regression were used to analyze the factors influencing vaginal microbiota.Analysis of variance and Kruskal Wallis test were used for statistical analysis of continuous variables,and Chi-square test and Fisher′s exact test were used for categorical data.The differences were considered statistically significant when the P value was less than 0.05.Results This study enrolled 91 pregnant women(91 vaginal samples)with an average age of(27.37±3.60)years.There were 18,56 and 17 vaginal samples collected at the median gestational age of 11.93 weeks(the first trimester),19.43 weeks(the second trimester)and 38.29 weeks(the third trimester),respectively.The relative abundance of Firmicutes and Lactobacillus was 91.30%and 87.67%,respectively.Lactobacillus iners and Lactobacillus crispatus had a relative abundance of 43.95%and 36.33%,respectively.Moreover,Lactobacillus iners-dominated vaginal microbiota was detected in all trimesters.The number of samples with high relative abundance of Lactobacillus iners gradually decreased with gestational age.Lactobacillus crispatus-dominated vaginal microbiota was found in the second and third trimesters and the number of samples with high relative abundance gradually increased during pregnancy.The Alpha diversity of vaginal microbiota had a decreasing trend during the gestation.There were significant differences in Pielou′s Evenness diversity index of vaginal microbiota between different smoking groups(P<0.05)and in Shannon diversity index between different drinking groups(P<0.05).There were significant differences in Chao1,Observed Features and Faith_pd diversity index of vaginal microbiota between pregnant women with different education(P<0.05)and in Shannon and Simpson diversity index between different income groups(P<0.05).Conclusions Vaginal microbiota was dominated by Lactobacillus in normal pregnant women.The dominance of Lactobacillus iners gradually decreased,while that of Lactobacillus crispatus increased during gestation.In normal pregnant women,the Alpha diversity of vaginal microbiota was correlated with smoking,drinking,education and family annual income.Smoking cessation and drinking before pregnancy were related to lower Alpha diversity of vaginal microbiota in pregnant women,while lower education and higher family income were associated with higher Alpha diversity.