Detection of Vibrio cholerae and V-mimicus heat-stable toxin gene sequence by PCR

Previously the heat-stable enterotoxin in Vibrio cholerae and V. mimicus has been detected by suckling mouse assay, a non-specific approach, and by DNA probes, a time-consuming method. This report describes a polymerase chain reaction (PCR) procedure for the detection of the stn (NAG-ST) and sto (O1-ST) gene sequences that is rapid and specific, allowing toxin gene molecular characterisation. A total of 34 V. cholerae and V. mimicus isolates was examined for ST and CT genes. The NAG-ST gene sequence was amplified in 13 of 22 non-O1/non-O139 V. cholerae and three of five V. mimicus strains. A new enterotoxin gene sequence pattern was found with MseI and TagI restriction endonuclease PCR fragment digestion of two V. cholerae isolates, in addition to the pattern anticipated from the Genbank sequence, and found with the other ST+. These results show that ST-PCR detection is useful for the characterisation of V. cholerae and V. mimicus.