Nanogold-based immunochromatographic strip test for rapid detection of clinical and environmental strains of Vibrio cholerae

A nanogold-based immunochromatographic strip test (VCG strip test) for the detection of all 70 isolates of Vibrio cholerae including O1, O139, and non-O1/O139 (NVCs) was developed using two monoclonal antibodies (MAbs), namely VC-63 and VC-201, which bound specifically to 10 and 15 kDa proteins. Direct detection of V. cholerae in experimentally spiked fresh seafood samples such as shrimp, blood clam, mussel, and oyster could be achieved with sensitivities of 10(7) CFU/ml, which was similar to that of the dot blotting test using each MAb. The detection sensitivity could be improved to 10(3) or 10 or 1 CFU/ml of original bacterial content after preincubation of the sample in alkaline peptone water for 6, 12, and 24 hr consecutively. However, the detection sensitivities were also dependent on the content of other bacteria in the sample that might compete or inhibit the growth of V. cholerae during the preenrichment step. Due to its broad specificity, simplicity and rapid result generation, the VCG strip test can be used for the preliminary detection of V. cholerae at point of care for both environmental and clinical strains to assist appropriate decision or epidemiological surveillance of virulent V. cholerae strains (including NVC strains), which are ubiquitous in the environment and seafood.

Automated summary

The study developed a nanogold-based immunochromatographic strip test for rapid and accurate detection of various Vibrio cholerae strains, suitable for preliminary detection of cholera pathogens in fresh seafood. While detection sensitivity can be enhanced through preincubation, the presence of other bacteria in the sample may influence the test results.