Diversity of Lactobacilli Associated with Severe Early Childhood Caries

描述(申请人提供)：这项申请的长期目标是揭示一组称为乳杆菌(Lb)的细菌的特征，这种细菌在儿童和成人的龋齿进展和严重程度中发挥关键作用。近一个世纪以来，人们已经知道了龋齿和乳酸菌之间的联系，但在确定100多种乳酸菌中哪一种是导致龋齿的进一步进展仍然难以捉摸。遗传方法的最新进展和十几个lb基因组的公布使人们有可能对lb成员的亚群和导致龋齿的致龋性特征有重要的了解。这些目标将通过两个具体目标来实现。目的1调查儿童早期重度龋病组(S组)和无龋组(CF组)和中度活动龋组(白斑病变组)儿童Lb的分布。我们将通过独立于文化和依赖于文化的方法来实现这些目标，以获得对磅种群丰度和多样性的估计。我们还将通过AP-PCR鉴定在这三组中发现的个别Lb基因类型。通过16SRRNA基因测序，将完成唯一基因型的Lb物种鉴定，以获得代表S-ECC、WSL和CF栖息地或生态位特征的不同物种/基因型的分离物集合。目标2是确定与龋齿生态位相关的遗传属性。将全基因组测序和比较基因组学应用于来自AIM 1的分离株，再加上公共和私人数据库中提供的非口腔Lb基因组序列，将导致识别独特的基因特征，这些基因特征是龋齿/无龋生态位所特有的。有了这些信息，临床医生将能够分析口腔中的细菌样本，并确定存在的lb是否会导致龋齿。反过来，这将为临床医生提供对龋齿风险和严重程度的估计。这些发现的一个重要副产品将为评估作为健康相关益生菌的lb的致龋性铺平道路。

DESCRIPTION (provided by applicant): The long-term objective of this application is to uncover the characteristics of a group of bacteria called the lactobacilli (Lb) that play a key role in the progression and severity of dental caries in both children and adults. For almost a century, the link between caries and Lb was known, but further progress in delineating which of the more than 100 species of lactobacilli were responsible for dental caries remained elusive. Recent advances in genetic methods and the publication of a dozen Lb genomes now make it possible to gain important insight into the sub-group of Lb members and the cariogenic traits responsible for caries. These goals will be met by two specific aims. Aim 1 is to conduct a survey of the Lb populations in three groups of children, those with severe early childhood caries (S-ECC) and two comparison groups, a caries free (CF) and a moderately active caries (white spot lesion, WSL) group. We will accomplish these aims by both culture-independent and culture-dependent methods to obtain estimates of abundance and diversity of the Lb populations. We will also identify individual Lb genotypes found in the three groups by AP-PCR. Lb species identification of unique genotypes will be accomplished by 16S rRNA gene sequencing to obtain a collection of isolates that represent the different species/genotypes that characterize the S-ECC, WSL, and CF habitat or niche. Aim 2 is to identify genetic attributes associated with the caries-niche. A combination of whole-genome sequencing and comparative genomics applied to the isolates derived from Aim 1, coupled with non-oral Lb genome sequences available in public and private database, will result in the identification of genetic signatures unique to the caries/caries-free niche. With this information, clinicians will be able to analyze a bacterial sample from the mouth and determine whether the Lb present are cariogenic or not. This, in turn, will give clinicians an estimation of risk for, and severity of, dental caries. An important spin off to these findings will pave the way toward assessing the cariogenic potential of Lb proposed as health-associated probiotics.