Association of cytolethal distending toxin locus cdtB with enteropathogenic Escherichia coli isolated from patients with acute diarrhea in Calcutta, India

Among Escherichia coli strains isolated from stool specimens from patients with acute diarrhea, 1.4% were found to harbor cdtB by use of enrichment cytolethal distending toxin (CDT) PCR. These isolates were identified as being enteropathogenic E. coli (EPEC). In a retrospective study using a probe hybridization assay, 6 of 138 EPEC strains were found to harbor the cdtB locus. cdtB-positive isolates mostly belong to the O86a and O127a serogroups, with the former being associated with higher expression of CDT. Pulsed-field gel electrophoresis profiles showed that the EPEC strains harboring cdtB strains are genetically diverse.