Vibrio cholerae is a Gram-negative facultative anaerobic bacteria.
V. cholerae naturally exists in brackish or salt water, where they easily attach to the chitin-containing shells of crabs, shrimps and other shellfish. Human pathogenic V. cholerae cause the deadly cholera disease, which can be caused by eating undercooked or raw marine organisms. Epidemic cholera strains become virulent by acquiring the CTX phage which enables V. cholerae to attach to the intestinal lumen and producing cholera toxin. The activated product of the ctxAB gene is responsible for the intracellular toxicity of cholera toxin.

Cholera toxin (ctx) gene is critical in causing cholera disease. Infections with some strains lacking the ctx gene may also lead to disease in humans, but these cases are much less serious and life-threatening. The presence of the ctxAB gene as a molecular marker can be used for distinguishing toxigenic cholera from non-virulent strains of V. cholerae.

Real Time PCR reaction is a triplex-type. FAM channel serves for detection of the DNA sequences specific for Vibrio cholerae whereas DNA sequences specific for the ctxAB virulence gene are detected in the Texas Red channel. Whereas, the HEX channel is reserved for monitoring of the internal control amplification. Additionally, diagnostic panel contains negative and positive controls allowing to monitor the whole aspects of the Real Time PCR. Positive control was obtained using genetic engineering.