Detection of the cytolethal distending toxin locus cdtB among diarrheagenic Escherichia coli isolates from humans in Iran
Detection of the cytolethal distending toxin locus cdtB among diarrheagenic Escherichia coli isolates from humans in Iran
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DOI：
10.1016/j.resmic.2004.09.011
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发表时间：
2005-03-01
影响因子：
2.6
通讯作者：
Oswald, E
中科院分区：
文献类型：
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作者：
Bouzari, S;Oloomi, M;Oswald, E
细胞致死性膨胀毒素（CDT）代表了一个新出现的家族，由许多病原体产生的新描述的细菌产物。编码该毒素的基因被鉴定为三个相邻基因（cdt-A、cdt-B和cdt-C）的簇。迄今为止，已经鉴定了五种cdt遗传变体，命名为cdt-I、cdt-II、cdt-III、cdt-IV和cdt-V。为了确定大肠杆菌分离株中cdt基因的存在，采用PCR测定。利用设计的检测大肠杆菌的多重引物。colicdt基因，PCR检测结果显示37.5%的菌株含有cdt基因。而特异性引物位于cdt-B基因座检测cdt-I，cdt-II，cdt-III和cdt-IV，在多重PCR阳性菌株表明，cdt-I-like基因存在于这些菌株的45.3%。然而，在52%的分离株中，可检测到cdt-III样基因。值得一提的是，在30.8%的分离株中，同时检测到cdt-II和cdt-III。在2.6%的分离株中，存在cdt-III基因。cnf-1基因在29.4%的携带cdt-I基因的菌株中被检测到，然而，cnf-2基因仅在23.1%的cdt-III样菌株中被检测到。此外，PCR分析结果表明，在我们的大肠杆菌中存在cdt样基因。大肠杆菌分离株，尽管在CHO细胞试验中，所有分离株均显示出CDT特有的细胞病变效应。(c)2004年，Elsevier SAS。All rights reserved.
Cytolethal distending toxin (CDT) represents an emerging family of newly described bacterial products that are produced by a number of pathogens. Genes encoding this toxin were identified as a cluster of three adjacent genes, cdt-A, cdt-B and cdt-C. Five cdt genetic variants, designated cdt-I, cdt-II, cdt-III, cdt-IV and cdt-V, have been identified so far. To determine the presence of cdt genes among Escherichia coli isolates, a PCR assay was employed. Using multiplex primers designed for detection of E. coli cdt genes, PCR analysis indicated the presence of cdt genes in 37.5% of these isolates. While specific primers were located in the cdt-B locus for detection of cdt-I, cdt-II, cdt-III and cdt-IV, in multiplex PCR positive isolates indicated that a cdt-I-like gene was present in 45.3% of these isolates. However, in 52% of the isolates, the cdt-III-like gene could be detected. It should be mentioned that in 30.8% of these isolates, cdt-II and -III were detected simultaneously. In 2.6% of the isolates, the cdt-III gene was present. The cnf-1 gene was detected in 29.4% of strains carrying the cdt-I gene; however, the cnf-2 gene was detected only in 23.1% of the cdt-III-like strains. Furthermore, the data obtained by PCR analysis indicated the presence of cdt-like genes among our E. coli isolates, although in the CHO cell assay, all isolates showed a cytopathic effect characteristic of CDT. (c) 2004 Elsevier SAS. All rights reserved.