Streptococcus mutans, a primary bacterium associated with dental caries, has four known clinical serotypes (c, e, fand k). Certain serotypes, the presence of multiple serotypes and strains with collagen‐binding proteins (CBP, Cnm and Cbm) have been linked with systemic disease. Evaluation of S mutans serotype distribution and caries association is needed in the United States. The purpose of this study was to evaluate the prevalence of S mutans serotypes from two cohorts of African‐American children in rural Alabama using three sample types (saliva, plaque and individual S mutans isolates) by PCR detection for association with caries. Detection of CBP was also performed by PCR. In total, 129 children were evaluated and overall prevalence of serotypes were: serotype c(98%), e(26%), f(7%) and k(52%). Serotype c was statistically associated with higher caries scores in older children (P < 0.001) and serotype k was statistically more likely in females (P = 0.004). Fourteen per cent of children had CBP. Thirteen S mutans isolates from five children tested positive for both CBP. This study is the first to report on the prevalence of S mutans serotypes in a US population using the PCR‐based approach. The frequency of serotype k in this study is the highest reported in any population, illustrating the need for further study to determine the prevalence of this clinically relevant serotype in the US. This is the first study to report S mutans isolates with both Cnm and Cbm in the same strain, and further analysis is needed to determine the clinical significance of these strains.

中文翻译：

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通过 PCR 分析龋齿儿童中的变形链球菌血清型和胶原结合蛋白 Cnm/Cbm。

变形链球菌是一种与龋齿相关的主要细菌，有四种已知的临床血清型（c、e、f和k）。某些血清型、多种血清型和具有胶原结合蛋白（CBP、Cnm 和 Cbm）的菌株的存在与全身性疾病有关。美国需要对变形链球菌血清型分布和龋齿关联进行评估。本研究的目的是使用三种样本类型（唾液、菌斑和个体变形链球菌分离株）通过 PCR 检测来评估阿拉巴马州农村地区两组非裔美国儿童中变形链球菌血清型的流行情况，以了解其与龋齿的关系。还通过PCR进行CBP的检测。总共对 129 名儿童进行了评估，血清型的总体患病率是：血清型c (98%)、e (26%)、f (7%) 和k (52%)。血清型c与年龄较大儿童的较高龋齿评分存在统计学相关性（P  < 0.001），而血清型k在女性中更有可能发生（P  = 0.004）。14% 的儿童患有 CBP。来自 5 名儿童的13 株变形链球菌分离株的两种 CBP 检测均呈阳性。本研究首次使用基于 PCR 的方法报告美国人群中变形链球菌血清型的流行情况。本研究中k血清型的出现频率是所有人群中报告最高的，表明需要进一步研究以确定这种临床相关血清型在美国的流行率。这是第一项报告同一菌株中同时具有 Cnm 和 Cbm 的变形链球菌分离株的研究，需要进一步分析以确定这些菌株的临床意义。