Distribution correlation of P. gingivalis and S. cristatus in dental plaque

描述（由申请人提供）：成人牙周炎在不同种族之间呈明显分布，与非西班牙裔白人相比，非西班牙裔黑人的发病率显著更高，即使考虑到糖尿病等协变量和其他健康和社会因素。据报道，正如预期的那样，患有牙周炎的有齿受试者对口腔病原体牙龈卟啉单胞菌的滴度高于没有牙周炎的受试者。本实验室首次报道了冠状链球菌和牙龈卟啉单胞菌之间的属间交流。我们鉴定了一个S. cristatus，精氨酸脱亚胺酶（ArcA），作为信号 牙龈卟啉单胞菌通过抑制fimA基因的表达对其作出反应的分子，fimA基因编码长菌毛的主要亚基蛋白。后者是牙龈卟啉单胞菌的细菌定殖和宿主细胞侵袭所必需的。因此，本项目将检验以下假设：a）S. cristatus作为一种有益的细菌，在预防牙龈卟啉单胞菌在口腔中的定植中起重要作用;和B）牙龈卟啉单胞菌的发病率增加， 非裔美国人的牙周炎可能是由于口腔S. cristatus：与白人相比，这些受试者中的牙龈卟啉单胞菌，或者FimA基因型在黑人与白人中可能不同。因此，我们的目标是：1）确定S的分布。目的：比较牙周炎患者和牙周健康者牙菌斑中的菌群（尤其是S. cristatus和牙龈卟啉单胞菌），在非洲裔美国人与高加索人在每组内;和2）检查这些患病率的相关性S。Cristatus和牙龈卟啉单胞菌具有不同的FimA基因型。为了实现这些目标，我们将招募三组受试者：牙周组织健康的受试者，或中度与重度牙周炎的受试者。每组将由成年非裔美国人和高加索男性和女性组成。排除标准将包括糖尿病、艾滋病毒/艾滋病和其他健康标准，如怀孕。所有受试者将接受牙周状况的全口检查和病史。将采集牙菌斑中的微生物样本。S.将通过qPCR分析确定冠状菌和牙龈卟啉单胞菌的感染率，以及不同FimA基因型的患病率。我们预计，拟议的研究将提供有关牙周炎发病机制的重要信息，以及在这两个人群中发现的微生物生物膜，并将为未来的扩展研究铺平道路，从长远来看，重点是制定针对消除牙龈卟啉单胞菌定植的适当干预策略。

DESCRIPTION (provided by applicant): Adult periodontitis is disproportionally distributed among races, and has a significantly higher incidence in non- Hispanic blacks compared to non-Hispanic whites, even when co-variates such as diabetes and other health and social factors have been taken into account. Titers to the oral pathogen P. gingivalis are reported to be higher, as anticipated, in dentate subjects with, compared to those without periodontitis. Our laboratory was to first to report an intergeneric communication between Streptococcus cristatus and P. gingivalis. We identified a surface protein of S. cristatus, arginine deiminase (ArcA), as a signal molecule to which P. gingivalis responds by repressing the expression of the fimA gene, which codes for the major subunit protein of long fimbriae. The latter is required for bacterial colonization of P. gingivalis and host cell invasion. Therefore this project will test the hypothess that: a) S. cristatus serves as a beneficial bacterium and plays an important role in the prevention of P. gingivalis colonization of the oral cavity; and b) that the increased incidence of periodontitis in African-Americans may be due to either a decreased ratio of oral S. cristatus: P. gingivalis in these subjects compared to whites, or that the FimA genotypes may differ in blacks vs. whites. Our aims therefore are to: 1) determine the distribution of S. cristatus and P. gingivalis in dental plaques of those with moderate periodontitis, severe periodontitis and periodontal healthy individuals, and compare microbial profiles (especially S. cristatus and P. gingivalis), in Africa Americans versus Caucasians within each group; and 2) to examine the correlation of these prevalence of S. cristatus and P. gingivalis with different FimA genotypes. To achieve these aims, we will recruit three groups of subjects: those with a healthy periodontium, or with moderate versus severe periodontitis. Each group will be composed of adult African American and Caucasian males and females. Exclusion criteria will include diabetes, HIV-AIDs and other health criteria such as pregnancy. All subjects will receive a full-mouth examination of periodontal status and a medical history. Microbial samples from dental plaque will be collected. The prevalence of S. cristatus and P. gingivalis will be determined by qPCR analysis, as will the prevalence of different FimA genotypes. We anticipate that the proposed studies will provide important information regarding the pathogenesis of periodontitis, and the microbial biofilms found in these two populations and will pave the way for extended studies in future, focused in the longer term on the development of appropriate interventional strategies targeting at eliminating of P. gingivalis colonization.