CHARACTERIZATION OF VIBRIO CHOLERAE O1 ISOLATED IN VIETNAM

V cholerae O1 isolated in Vietnam in 1995 and 2000 were characterized. Most of the isolates in 2000 showed moderate resistance to tetracycline and chloramphenicol, and strong resistance to sulfamethoxazoltrimethoprim. The susceptibilities to ampicillin, erythromycin, nalidixic acid and ofloxacin were not very different from those of the isolates in 1995. V cholerae O1 strains showing this kind of drug susceptibility pattern are unique to the seventh cholera pandemic, and they have become widely distributed in Southeast Asian countries. Genetic analysis of the strains from Vietnam by arbitrarily primed polymerase chain reaction suggested that they might be clonal derivatives. In prophage type, 6 of 20 strains (30%) in 1995 and 1 of 24 strains (4%) in 2000 belonged to Ubol type. Considering the current spreading of V cholerae O1 with such unique susceptibility to the drugs, we recommend careful monitoring of the drug susceptibility of V cholerae O1 throughout the world.