Class 1 integron-borne, multiple-antibiotic resistance encoded by a 150-kilobase conjugative plasmid in epidemic Vibrio cholerae O1 strains isolated in Guinea-Bissau

in the 1996-1997 cholera epidemic in Guinea-Bissau. surveillance for antimi crobial resistance showed the emergence of a multidrug-resistant strain of Vibrio cholerae O1 during the course of the epidemic. The strain was resist ant to ampicillin, erythromycin, tetracycline? furazolidone, aminoglycoside s, trimethoprim, and sulfamethoxazole. Concomitant with the emergence of th is strain, we observed a resurgence in the number of registered cholera cas es as web as an increase in the case fatality rate from 1.0% before the eme rgence of the multiple-drug-resistant strain to 5.3% after the emergence of the strain. Our study shows that the strain contained a 150-kb conjugative multiple-antibiotic resistance plasmid with class 1 integron-borne gene ca ssettes encoding resistance to trimethoprim (dhfrXII) and aminoglycosides [ ant(3 "-1a]). The finding of transferable resistance to almost all of the a ntibiotics commonly used to treat cholera is of great public health concern . Studies should be carried out to determine to what extent the strain or i ts resistance genes have been spread to other areas where cholera is endemi c.