不同人群唾液中变形链球菌的定量检测及其意义

目的 建立定量检测唾液样本中变形链球菌和细菌总数的方法 ,比较变形链球菌和细胞总数的存在与不同人群中龋齿患病率的关系.方法 针对染色体DNA印迹法检测变形链球菌中出现的14 kb的HaeⅢ酶切片段,合成特异性引物(Sm~*),运用实时荧光定量聚合酶链反应(PCR)技术定量检测变形链球菌;对单纯随机抽样方法 抽取的99份唾液标本按照龋齿牙数是否为0分为龋齿组和无龋组,龋齿组72人,无龋组27人(包括从未患过龋齿者和曾患龋齿但已经过治疗和填充的无新鲜龋齿者),分别进行变形链球菌和细菌总量的检测及统计学分析.结果引物Sm~*仅对变形链球菌有特异性,定量PCR可检测的下限为0.1 μg/L;细菌总数在龋齿组和无龋组分别为51.4×10~8个/L和221.6×10~8个/L,变形链球菌占细菌总数比值分别为0.0193和0.0059,细菌总数和变形链球菌所占比值在两组间差异有统计学意义(P=0.022).结论 引物Sm~*可用于变形链球菌的定量检测;唾液中变形链球菌与总细菌数的比值与龋齿患病率相关.

Quantitative detection of Streptococcus mutans in different people with dental caries by real-time polymerase chain reaction

Objective To establish a quantity detection method of Streptococcus mutans(Sm)and bacteria and compare the relationship between the number of these bacteria and the prevalence of dental caries in different people.Methods With specific primers for a unique sequence in a 14 kb Hae Ⅲ restriction fragment consistently presenting during detecting Sm by chromosomal DNA fingerprints,the total number of Sm and bacteria of 99 saliva samples were detected by real-time polymerase chain reaction(PCR)and statistically analyzed.Results The primers were specific for Sm and the minimum detectable level by real-time PCR was 0.1 μg/L.The total number of bacteria in the dental caries and people without caries was 51.4×10~8 cell copies/L and 221.6×10~8 cell copies /L respectively,in which the ratio of Sm to bacteria was 0.0193 and 0.0059 respectively.The differences were significantly different between the people with dental caries and those without caries in the total number of bacteria and the ratio of Sm to bacteria.Conclusions The primers can be used to detect the Sm by real-time PCR.The ratio of Sm to bacteria was closely associated with the prevalence of dental caries.