title: An improved technique for isolation of environmental Vibrio cholerae with epidemic potential: monitoring the emergence of a multiple-antibiotic-resistant epidemic strain in Bangladesh.
abstract: Predicting cholera epidemics through monitoring the environment for the presence of pathogenic Vibrio cholerae is complicated by the presence in water of a large number of mostly nonpathogenic V. cholerae strains. V. cholerae strains causing recent cholera epidemics in Bangladesh carry the sulfamethoxazole-trimethoprim (SXT) element, which encodes resistance to several antibiotics. Here, we show that the use of a culture medium containing streptomycin, sulfamethoxazole, and trimethoprim (the antibiotic selection technique [AST]) can significantly enhance the isolation of environmental V. cholerae O1 with epidemic potential (P<.001). The AST was also used to monitor the recent emergence and spread of a new multiple-antibiotic-resistant strain of V. cholerae in Bangladesh. The results of this study support the hypothesis that pre-epidemic amplification of pathogenic V. cholerae occurs in the human host and leads to the start of an epidemic cycle dominated by a single clone of V. cholerae that spreads rapidly through environmental waters.
authors.affiliation: Molecular Genetics Laboratory, Laboratory Sciences Division, International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka, Bangladesh. faruque@icddrb.org
authors.forename: Shah M
authors.initials: SM
authors.lastname: Faruque
authors.forename: M Johirul
authors.initials: MJ
authors.lastname: Islam
authors.forename: Qazi Shafi
authors.initials: QS
authors.lastname: Ahmad
authors.forename: Kuntal
authors.initials: K
authors.lastname: Biswas
authors.forename: A S G
authors.initials: AS
authors.lastname: Faruque
authors.forename: G Balakrish
authors.initials: GB
authors.lastname: Nair
authors.forename: R Bradley
authors.initials: RB
authors.lastname: Sack
authors.forename: David A
authors.initials: DA
authors.lastname: Sack
authors.forename: John J
authors.initials: JJ
authors.lastname: Mekalanos
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001431:Bacteriological Techniques; D001459:Bangladesh / Q000453:epidemiology; D002771:Cholera / Q000453:epidemiology / Q000382:microbiology*; D003470:Culture Media / Q000737:chemistry; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D004196:Disease Outbreaks; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D017720:Molecular Epidemiology; D016133:Polymerase Chain Reaction; D021521:Ribotyping; D012641:Selection, Genetic; D013307:Streptomycin / Q000494:pharmacology; D014296:Trimethoprim Resistance / Q000235:genetics; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000494:pharmacology; D041241:Vibrio cholerae O1 / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D014871:Water Microbiology
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D004269:DNA, Bacterial; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D013307:Streptomycin