用16S rRNA荧光定量PCR技术分析低出生体重儿肠道菌群变化及影响因素

The variation and influencing factors of intestinal microflora in low birth weight infants by using 16S rRNA quantitative PCR technique

目的监测低出生体重儿肠道细菌分布情况,并分析影响低出生体重儿肠道微生态平衡的因素。方法以低出生体重儿(1 500g≤体重<2 500g)为研究对象,采用16SrRNA荧光定量PCR技术检测新生儿出生后第1天、3天、7天粪便中双歧杆菌、乳杆菌、大肠埃希菌和肠球菌4种细菌的含量,比较正常新生儿与低出生体重儿肠道菌群构建的差异;分析不同胎龄、体重、喂养方式、疾病状态等因素对低出生体重儿肠道微生态平衡的影响。结果 (1)低出生体重儿组和健康新生儿组粪便中大肠埃希菌、肠球菌、乳杆菌和双歧杆菌含量与婴儿日龄呈明显正相关关系,且低出生体重儿组婴儿粪便4种细菌含量均明显低于健康对照组(P<0.05)。(2)2 000g≤体重<2 500g组低出生体重儿大肠埃希菌和肠球菌含量在各日龄明显高于体重<2 000g组新生儿(P<0.05),双歧杆菌和乳杆菌含量在3日龄和7日龄阶段明显高于体重<2 000g组(P<0.05),而1日龄阶段差异无统计学意义(P>0.05)。(3)母乳喂养组在3日龄和7日龄阶段双歧杆菌和乳杆菌含量明显高于乳制品喂养组(P<0.05)。(4)无并发症患儿组在3日龄和7日龄阶段乳杆菌和双歧杆菌含量明显高于有并发症组(P<0.05)。结论低出生体重儿肠道菌群构建规律异于正常新生儿,尤其是乳杆菌和双歧杆菌的定植差异更为突出;低出生体重儿的出生体重与肠道乳杆菌和双歧杆菌的含量呈正相关;母乳喂养对低出生体重儿肠道中益生菌的定植有明显的优势;新生儿相关疾病直接影响低出生体重儿肠道微生态的构建,可导致其胃肠道生态系统的异常;16S rRNA荧光定量PCR技术适用于评价婴幼儿肠道微生态状况。

Objective To investigate the distribution and influencing factors of intestinal microflora in low birth weight（LBW）infants.Methods Newborns weighing from 1.5kg to 2.5kg were enrolled in the study,who′s fecal samples were tested for the levels of Bifidobacteria,Lactobacilli,Enterococci and Escherichia coli on the first,the third and the seventh day after birth by using 16 SrRNA quantitative PCR technique.The difference in the distribution of intestinal microflora between LBW infants and normal infants were observed,and the influencing factors such as gestational age,body weight,feeding patterns and health condition were analyzed.Results（1）There was a positive correlation between the infant day age and the levels of Bifidobacteria,Lactobacilli,Enterococci and E.coli in feces of LBW infants group and normal controls,and the levels of the four bacteria were obviously lower in LBW infants than in normal controls（P〈0.05）.（2）Comparing with the group of body weight less than 2.0kg,the levels of Enterococci and E.coli in the group of body weight 2.0kg to 2.5kg were obviously higher at each day age（P〈0.05）,and the levels of Bifidobacteriaand Lactobacilli were obviously higher at 3 and 7 day age（P〈0.05）.However,there was no statistical difference in the levels of Bifidobacteria and Lactobacilli between the two groups at 1 day age（P〈0.05）.（3）The levels of Bifidobacteriaand Lactobacilli were obviously higher in the breastfeeding group than in non-breastfeeding group at 3 and 7 day age（P〈0.05）.（4）At the age stage of 3 days and 7 days,the levels of Bifidobacteriaand Lactobacilliin the infants without complications were obviously higher than in those with complications（P〈0.05）.Conclusion The distribution of intestinal microflora in LBW infants,especially Bifidobacteriaand Lactobacilli,is different from that in normal controls.There is a positive correlation between the birth weight and the levels of Bifidobacteriaand Lactobacilliin feces of LBW infants.Breastfeeding is obviously beneficial to the colonization of intestinal probiotics in LBW infants.Complications such as hypoglycemia,jaundice,feeding intolerance and infections can directly impact the construction of intestinal probiotics in LBW infants,resulting in abnormal gastrointestinal microbiota.16 SrRNA quantitative PCR technique is suitable for evaluation of the intestinal microecological condition in infants.