PLASMID PROFILES AND ANTIMICROBIAL SUSCEPTIBILITY PATTERNS OF VIBRIO-CHOLERAE O1 STRAIN ISOLATED DURING A RECENT OUTBREAK IN NIGERIA

In a study on the outbreak of cholera in Nigeria in 1992, 86 strains o f Vibrio cholerae O1 (79 Ogawa serotype and 7 Inaba serotype) were iso lated. Antimicrobial susceptibility testing and plasmid profile analys is of the strains were done. Most isolates were highly sensitive to ci profloxacin, cefotaxime, chloramphenicol, gentamicin, erythromycin, na lidixic acid, and nitrofurantoin, and less sensitive to ampicillin, pe nicillin, cloxacillin, cotrimoxazole, streptomycin, and tetracycline. The strains showed 13 resistant patterns; the commonest resistant patt erns were Ap(r), Sm-r, and ApTc(r). A total of 41 (47.6%) strains cont ained one or more plasmid(s) with sizes ranging from 4.5 kilobase to 1 50 kilobase. Ten isolates were able to transfer resistant plasmids to Escherichia coli K-12 by conjugation. Antibiogram patterns distinguish ed more isolates than in plasmid profile analysis. Plasmids specifying resistance to ampicillin, tetracycline, and trimethoprim were found. The differing patterns of antibiogram and plasmid profiles indicated t hat many circulating strains were responsible for the last outbreak in the country.