Pahumunto Nuntiya, Ruangsri Praphansri, Wongsuwanlert Mutita, Piwat Supatcharin, Dahlen Gunnar, Teanpaisan Rawee
Common Oral Diseases and Epidemiology Research Center and the Department of Stomatology, Faculty of Dentistry, Prince of Songkla University, Hat-Yai, 90112, Thailand.
Department of Conservative Dentistry, Faculty of Dentistry, Prince of Songkla University, Hat-Yai, 90112, Thailand.
Anaerobe. 2015 Dec;36:60-4. doi: 10.1016/j.anaerobe.2015.10.012. Epub 2015 Oct 31.
A high proportion of non-serotypeable isolates of Aggregatibacter actinomycetemcomitans among Thai periodontitis cases has been previously reported. The aim of this study was to investigate the expression of leukotoxin and toxicity, cytolethal distending toxin (Cdts), and internalization and the killing effect on fibroblasts by A. actinomycetemcomitans subtypes from Thai chronic periodontitis cases. A total of 96 A. actinomycetemcomitans strains from 37 periodontitis cases, previously serotyped with PCR and subtyped with DGGE, were examined for the presence of the ltx gene and cdt genes (cdtBC), and tested for leukotoxin expression, leukotoxicity, internalization, and apoptosis of fibroblast cells. The ltx gene was present in all isolates, while 84.4% showed the cdtBC gene. Two strains with a JP2-like ltx gene with a deletion of 530 bp in the promoter region, serotyped as c, showed virulence of similar magnitude to the JP2 strain. Furthermore, a higher virulence was found in the two non-serotypeable DGGE subtypes, NS1 and NS2, compared with the serotypeable strains (serotype a-f, serotype b and d were absent). Generally, the virulence of strains obtained from deep periodontal pockets was higher than those isolated from shallow non-bleeding pockets. A. actinomycetemcomitans subtypes isolated from adult Thais with chronic periodontitis showed a highly variable virulence, leukotoxin expression, leukotoxicity, internalization and apoptosis of fibroblast, and are regulated both genetically and environmentally.
此前已有报道称，泰国牙周炎病例中高比例的伴放线聚集杆菌分离株为不可分型菌株。本研究的目的是调查来自泰国慢性牙周炎病例的伴放线聚集杆菌亚型的白细胞毒素表达和毒性、细胞致死性膨胀毒素（Cdts）、内化作用以及对成纤维细胞的杀伤作用。对37例牙周炎病例中分离出的96株伴放线聚集杆菌菌株进行检测，这些菌株先前已通过PCR进行血清分型，并通过变性梯度凝胶电泳（DGGE）进行亚型分析，检测其是否存在ltx基因和cdt基因（cdtBC），并测试白细胞毒素表达、白细胞毒性、内化作用以及成纤维细胞的凋亡情况。所有分离株均存在ltx基因，而84.4%的分离株显示存在cdtBC基因。两株具有类似JP2的ltx基因且启动子区域缺失530 bp的菌株，血清型为c，其毒力与JP2菌株相似。此外，与可分型菌株（血清型a - f，血清型b和d不存在）相比，在两种不可分型的DGGE亚型NS1和NS2中发现了更高的毒力。一般来说，从深部牙周袋中获得的菌株毒力高于从浅部无出血袋中分离出的菌株。从患有慢性牙周炎的成年泰国人分离出的伴放线聚集杆菌亚型显示出高度可变的毒力、白细胞毒素表达、白细胞毒性、内化作用以及成纤维细胞凋亡，并且受到遗传和环境因素的调控。
