Quadruplex real-time PCR assay for detection and identification of Vibrio cholerae O1 and O139 strains and determination of their toxigenic potential.
Vibrio cholerae is a natural inhabitant of the aquatic environment. However, its toxigenic strains can cause potentially life-threatening diarrhea. A quadruplex real-time PCR assay targeting four genes, the cholera toxin gene (ctxA), the hemolysin gene (hlyA), O1-specific rfb, and O139-specific rfb, was developed for detection and differentiation of O1, O139, and non-O1, non-O139 strains and for prediction of their toxigenic potential. The specificity of the assay was 100% when tested against 70 strains of V. cholerae and 31 strains of non-V. cholerae organisms. The analytical sensitivity for detection of toxigenic V. cholerae O1 and O139 was 2 CFU per reaction with cells from pure culture. When the assay was tested with inoculated water from bullfrog feeding ponds, 10 CFU/ml could reliably be detected after culture for 3 h. The assay was more sensitive than the immunochromatographic assay and culture method when tested against 89 bullfrog samples and 68 water samples from bullfrog feeding ponds. The applicability of this assay was confirmed in a case study involving 15 bullfrog samples, from which two mixtures of nontoxigenic O1 and toxigenic non-O1/non-O139 strains were detected and differentiated. These data indicate that the quadruplex real-time PCR assay can both rapidly and accurately detect/identify V. cholerae and reliably predict the toxigenic potential of strains detected.
Huang
Jianwei
J
Department of Microbiology, Xiamen Centre for Disease Control and Prevention, Xiamen 361021, Fujian Province, China.
Zhu
Yumei
Y
Wen
Huixin
H
Zhang
Jiafeng
J
Huang
Shijie
S
Niu
Jianjun
J
Li
Qingge
Q
D000818:Animals; D002771:Cholera / Q000382:microbiology*; D002772:Cholera Toxin / Q000235:genetics*; D005243:Feces / Q000382:microbiology; D005516:Food Microbiology; D005618:Fresh Water / Q000382:microbiology; D005798:Genes, Bacterial / Q000235:genetics; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*; D011892:Rana catesbeiana / Q000382:microbiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014734:Vibrio cholerae / Q000145:classification* / Q000235:genetics*; D041241:Vibrio cholerae O1 / Q000235:genetics*; D041242:Vibrio cholerae O139 / Q000235:genetics*; D014871:Water Microbiology
D002772:Cholera Toxin