Leung W Keung, Ngai Vincent K S, Yau Joyce Y Y, Cheung Becky P K, Tsang Paul W K, Corbet Esmonde F
Faculty of Dentistry, Prince Philip Dental Hospital, The University of Hong Kong, Hong Kong SAR, China.
J Periodontal Res. 2005 Jun;40(3):258-68. doi: 10.1111/j.1600-0765.2005.00805.x.
This study characterized Actinobacillus actinomycetemcomitans isolates from young Chinese aggressive periodontitis patients.
Subgingival plaque samples (two/subject) were collected from diseased subjects < 25 years old (n = 9, mean age 21.1 +/- 1.6 years) and age-matched periodontitis-free controls (n = 47, mean age 22.0 +/- 1.1 years). Selective and anaerobic culture were used. The serotype, leukotoxin gene (ltx) operon promoter and the cytolethal distending toxin (cdt) genes complex of the A. actinomycetemcomitans isolates were investigated. Effects of the isolates on non-keratinizing periodontal ligament epithelial cells monolayer were studied.
Diseased subjects had significantly higher full-mouth bleeding score (p = 0.002) and total viable counts from plaque samples (7.2 x 10(6) vs. 2.1 x 10(5) CFU/paperpoint, p < 0.005). A. actinomycetemcomitans was isolated from 67%/56% or 6%/4% of diseased or controls subject/sites, respectively (p < 0.001). The proportion of A. actinomycetemcomitans isolatable from aggressive periodontitis or periodontitis-free associated subgingival plaque was low (0.7% vs. 0.1%, p < 0.02). The serotype of the isolates was characterized. All isolates possessed 652-like ltx gene promoter and all but one serotype c isolate from a diseased patient had intact cdtABC genes. That particular strain appeared to confer the least cellular damages on periodontal ligament epithelial monolayer compared to others.
This preliminary study confirmed the notion of increased prevalence and quantity of A. actinomycetemcomitans associated with aggressive periodontitis in young patients. The overall ltx promoter and cdt characteristics of the A. actinomycetemcomitans isolates, however, were similar among the diseased and control groups. A strain lacking the cdtABC gene appeared to be less damaging to a periodontal ligament epithelial cell model. Further studies therefore are warranted to clarify the pathogenic role and potentials of A. actinomycetemcomitans in aggressive periodontitis.
本研究对来自中国年轻侵袭性牙周炎患者的伴放线放线杆菌分离株进行了特征分析。
从年龄小于25岁的患病受试者（n = 9，平均年龄21.1±1.6岁）和年龄匹配的无牙周炎对照者（n = 47，平均年龄22.0±1.1岁）中采集龈下菌斑样本（每位受试者两份）。采用选择性厌氧培养。研究了伴放线放线杆菌分离株的血清型、白细胞毒素基因（ltx）操纵子启动子和细胞致死性膨胀毒素（cdt）基因复合体。研究了分离株对非角质化牙周膜上皮细胞单层的影响。
患病受试者的全口出血评分显著更高（p = 0.002），菌斑样本中的总活菌数也更高（7.2×10⁶对2.1×10⁵CFU/纸尖，p < 0.005）。伴放线放线杆菌分别从67%/56%或6%/4%的患病或对照受试者/部位分离得到（p < 0.001）。可从侵袭性牙周炎或无牙周炎相关龈下菌斑中分离出的伴放线放线杆菌比例较低（0.7%对0.1%，p < 0.02）。对分离株的血清型进行了特征分析。所有分离株均具有652样ltx基因启动子，除一名患病患者的一株血清型c分离株外，所有分离株的cdtABC基因均完整。与其他菌株相比，该特定菌株对牙周膜上皮单层的细胞损伤似乎最小。
这项初步研究证实了年轻患者中与侵袭性牙周炎相关的伴放线放线杆菌患病率和数量增加的观点。然而，伴放线放线杆菌分离株的总体ltx启动子和cdt特征在患病组和对照组中相似。一株缺乏cdtABC基因的菌株对牙周膜上皮细胞模型的损伤似乎较小。因此，有必要进行进一步研究以阐明伴放线放线杆菌在侵袭性牙周炎中的致病作用和潜力。
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