Prevalence of cytolethal distending toxin production in periodontopathogenic bacteria
Prevalence of cytolethal distending toxin production in periodontopathogenic bacteria
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DOI：
10.1128/jcm.41.4.1391-1398.2003
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发表时间：
2003-04-01
影响因子：
9.4
通讯作者：
Sugai, M
中科院分区：
文献类型：
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作者：
Yamano, R;Ohara, M;Sugai, M
细胞致死膨胀毒素（CDT）是近年来发现的一种由多种慢性感染致病菌产生的毒力因子。根据大肠杆菌（Escherichia coli）和弯曲杆菌（Campylobacter）cdtB基因的不同区域设计了简并寡核苷酸引物，利用HeLa细胞生物测定法检测了73株牙周致病菌的cdtABC基因的产生，并通过PCR检测了cdtABC基因的存在。Sugai等人，Infect. Immun. 66：5008- 5019，1998）。45株A.放线菌属的菌株，但毒素的滴度在这些菌株之间有很大的差异。PCR结果表明，这些菌株中存在Y 4型cdt序列，而其余的A. PCR扩增和Southern杂交检测cdtABC基因均为阴性。在40个CDT阳性菌株中，用HindIII酶切的基因组DNA进行Southern杂交，发现至少有6种限制性片段长度多态性类型。这表明cdtABC侧翼区是高度多态性的，这可以部分解释培养上清液中CDT活性的变异性。在我们的实验条件下，其余的牙周致病菌的测试菌株没有检测到的CDT生产的HeLa细胞测定和PCR分析的cdtB序列。这些结果有力地表明CDT是一种独特的毒素，主要由A.放线菌属是牙周致病菌中的优势菌。
Cytolethal distending toxin (CDT) is a newly identified virulence factor produced by several pathogenic bacteria implicated in chronic infection. Seventy three strains of periodontopathogenic bacteria were examined for the production of CDT by a HeLa cell bioassay and for the presence of the cdt gene by PCR with degenerative oligonucleotide primers, which were designed based on various regions of the Escherichia coli and Campylobacter cdtB genes, which have been successfully used for the identification and cloning of cdtABC genes from Actinobacillus actinomycetemcomitans Y4 (M. Sugai et al., Infect. Immun. 66:5008-5019,1998). CDT activity was found in culture supernatants of 40 of 45 tested A. actinomycetemcomintans strains, but the titer of the toxin varied considerably among these strains. PCR experiments indicated the presence of Y4-type cdt sequences in these strains, but the rest of A. actinomycetemcomitans were negative by PCR amplification and also by Southern blot analysis for the cdtABC gene. In the 40 CDT-positive strains, Southern hybridization with HindIII-digested genomic DNA revealed that there are at least 6 restriction fragment length polymorphism types. This suggests that the cdtABC flanking region is highly polymorphic, which may partly explain the variability of the CDT activity in the culture supernatants. The rest of tested strains of periodontopathogenic bacteria did not have detectable CDT production by the HeLa cell assay and for cdtB sequences by PCR analysis under our experimental conditions. These results strongly suggested that CDT is a unique toxin predominantly produced by A. actinomycetemcomitans among periodontopathogenic bacteria.