An Enzyme-Linked Immunosorbent Assay for the Rapid Detection of Vibrio parahaemolyticus

A sandwich enzyme-linked immunosorbent assay (ELISA) was developed for the rapid detection of Vibrio parahaemolyticus in foods. The assay was based on the detection of two outer-membrane proteins (molecular weights 36,000 and 34,000) of V. parahaemolyticus . Following an 18-h incubation in alkaline peptone salt broth containing 0.1%Teepol, the culture supernatant was added to the microtiter plate coated with antibodies against the two outer-membrane proteins. After washing, the same antibodies absorbed with V. alginolyticus and labeled with horsemdish peroxidase were used as secondary antibodies. The detection limit of the assay for total outer-membrane proteins was 10 ng/ml. For 29 strains of V. parahaemolyticus and 73 strains (including 27 isolates of vibrios) of other bacteria tested, the sensitivity and specificity of the ELISA were 100 and 96%, respectively. Strains producing false positives were V. tubiashii , V. campbellii , and V. vulnificus . Of 23 seafood samples tested, V. parahaemolyticus was detected in 17 and 15 samples, respectively, by the ELISA and by a conventional culture method. V. parahaemolyticus was also detected in samples artificially inoculated with the microorganism at levels less than 10 colony-forming units (CFU) per g. Compared to the conventional culture methods, which may take 4 to 6 days to complete, the ELISA can detect low numbers of V.parahaemolyticus in foods with a total analytical time of only 24 h. The ELISA is recommended as a rapid screening method.