Diarrhea Research Today is a free monthly online journal that collates and summarizes the latest research about Diarrhea, including details on infant and child diarrhea, causes, treatment, pregnany. | ||||||||
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Detection of the cytolethal distending toxin locus cdtB among diarrheagenic Escherichia coli isolates from humans in Iran.Bouzari S, Oloomi M, Oswald E Molecular Biology Unit, Pasteur Institute of Iran, Tehran 13164, Iran. saeidbouzari@yahoo.com 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-IV 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. Published 7 March 2005 in Res Microbiol, 156(2): 137-44.
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