In a previous study using pure bacterial cultures in a PCR assay, a primer pair corresponding to a unique chromosomal region of Vibrio cholerae O139 Bengal generated an amplicon from only V. cholerae O139 Bengal. PCR with the same primer pair was used to screen 180 diarrheal stool specimens. All the 67 V. cholerae O139 culture-positive stool specimens were positive by PCR, and the remaining specimens, which contained either other recognized enteric pathogens or no pathogens, were all negative by PCR.

We isolated and characterized a Vibrio cholerae O139 Bengal-specific DNA region by arbitrary PCR. The fragment contains open reading frames encoding two potential glycosyltransferases possibly involved in capsular polysaccharide or lipopolysaccharide biosynthesis. In order to evaluate the possibility that this region could be used for the specific detection of V. cholerae O139 Bengal, a PCR system was established. The specificity and sensitivity of the PCR were investigated by analyzing 240 strains within the family Vibrionaceae and 178 strains of other gram-negative bacteria. All V. cholerae O139 Bengal strains tested were positive, and none of the 384 control strains were amplified. The sensitivity of the assay was 10 2 CFU/ml.