Comparison between a TaqMan Polymerase Chain Reaction Assay and a Culture Method for ctx-Positive Vibrio cholerae Detection

The main objective of the present work was to evaluate a real-time polymerase chain reaction (PCR) method to detect toxigenic Vibrio cholerae in Pangasius hypophthalmus, a freshwater fish cultured mainly in South East Asia. A FDA traditional culture method and a real-time PCR method of the ctx gene were used for detection of V. cholerae in spiked samples of pangasius fish. After an overnight enrichment of samples at 37 degrees C in alkaline peptone water, 2 cfu/25 g of fish was detected with both methods. Although both methods were very sensitive, obtaining results with culture methods may take several days, while real-time PCR takes only a few hours. Furthermore, with traditional methods, complementary techniques such as serotyping, although not available for all serogroups, are needed to identify toxigenic V. cholerae. However, with real-time PCR, toxigenic serogroups are detected in only one step after overnight enrichment.