口腔微生物菌群分布与儿童龋病的关系研究

Study on the relationship between the distribution of oral microflora and caries in children

目的分析口腔微生物菌群分布与儿童龋病的关系,为预防儿童龋病提供理论依据。方法选取有龋(dmfs>6)患儿30例为患龋组,无龋(dmfs=0)患儿30例为对照组,分别采集牙菌斑,用变性梯度凝胶电泳技术(DGGE电泳)分析16SrDNA特征序列,观察DGGE电泳条带,并比对16SrDNA基因克隆文库,获得细菌鉴定结果,运用实时荧光定量PCR(Real-Time PCR)定量分析主要致龋菌水平。结果60例患者牙菌斑中共检出门类5个,属类28个及种系型88个。患龋组菌斑门类、属类与对照组比较差异无统计学意义(P>0.05),患龋组种系型较对照组种系型显著减少(P<0.05);Real-Time PCR显示患龋组牙菌斑中轻链球菌、血链球菌及口腔链球菌扩增的基因型数目较对照组明显减少(P<0.05),但变异链球菌及远缘链球菌基因型数目与对照组比较差异无统计学意义(P>0.05);患龋组口腔牙菌斑总基因型数目少于对照组(P<0.05)。Real-Time PCR还显示患龋组的远缘链球菌、变异链球菌、内氏放线菌及黏性放线菌比例均高于对照组(P<0.05)。结论与健康儿童相比龋病患儿口腔微生物菌群多样性减少,致龋菌远缘链球菌、变异链球菌、内氏放线菌和黏性放线菌致病菌比例升高,可为预防儿童龋病提供理论依据。

Objective To analyze the relationship between the distribution of oral microflora and caries in children and provide theoretical basis for the prevention of caries in children.Method 30 cases of children with caries(dmfs>6)and 30 cases of children without caries(dmfs=0)were selected as the caries group and the control group.The plaques was collected.Denaturing gradient gel electrophoresis(DGGE electrophoresis)was used to analyze 16SrDNA characteristic sequence,DGGE electrophoresis bands were observed and the result of bacterial identification was compared with 16SrDNA gene clone library.The levels of major cariogenic bacteria were analyzed by real-time fluorescence quantitative PCR.Results 5 phyla,28 genera and 88 phylotypes were detected in dental plaque of 60 subjects.Comparing the 16SrDNA characteristic sequences of plaque between the two groups,there was no significant difference in plaque phylum and genus between the caries group and the control group(P>0.05).The genotype of caries group was significantly reduced compared with the control group(P<0.05).Real-Time PCR showed that the number of amplified genotypes of Streptococcus mutans,Streptococcus sanguis and Streptococcus oralis in dental plaque of caries group was significantly lower than that of control group(P<0.05),but the number of genotypes of Streptococcus mutans and Streptococcus sobrinus was not significantly different from that of control group(P>0.05).The number of total genotypes of dental plaque in caries group was less than that of control group(P<0.05).The proportions of Streptococcus sobrinus,Streptococcus mutans,Actinomyces Neisseriae and Actinomyces viscosus were significantly higher in the caries group than in the control group(P<0.05).Conclusion Compared with healthy children,the diversity of oral microflora in children with caries is reduced,and the proportion of four cariogenic bacteria,Streptococcus sobrinus,Streptococcus mutans,Actinomyces nellii and Actinomyces mucinosa is increased,which can provide theoretical basis for the prevention of caries in children.