An improved technique for isolation of environmental Vibrio cholerae with epidemic potential: monitoring the emergence of a multiple-antibiotic-resistant epidemic strain in Bangladesh.
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.
Faruque
Shah M
SM
Molecular Genetics Laboratory, Laboratory Sciences Division, International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka, Bangladesh. faruque@icddrb.org
Islam
M Johirul
MJ
Ahmad
Qazi Shafi
QS
Biswas
Kuntal
K
Faruque
A S G
AS
Nair
G Balakrish
GB
Sack
R Bradley
RB
Sack
David A
DA
Mekalanos
John J
JJ
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
D000900:Anti-Bacterial Agents; D003470:Culture Media; D004269:DNA, Bacterial; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D013307:Streptomycin