Rapid method for visual detecting pathogenic Vibrio parahaemolyticus in food by loop-mediated isothermal amplification

A loop-mediated isothermal amplification technique was established to detect pathogenic Vibrio parahaemolyticus by using tdh gene in this paper. Six primers including two outer primers F3/B3, two inner primers FIP/BIP and two loop primers LF/LB were designed according to the highly conserved tdh gene of Vibrio parahaemolyticus. All bacteria strains including 6 pathogenic Vibrio parahaemolyticus strains and 15 other bacterial strains were amplified by using the primers with Bst DNA polymerase at 60℃. Among the 21 bacteria strains, only pathogenic Vibrio parahaemolyticus strains were LAMP positive result, which indicated that the LAMP primers designed were highly specific for target bacteria. The sensitivity of LAMP assay for Vibrio parahaemolyticus reached to 9.42 cfu/m L for the pure culture and 25.3cfu/25 g for the tested contaminated food. The test could complete in 40 ~60min. The LAMP assay established in this study was a sensitive, rapid and simple tool for detecting Vibrio parahaemolyticus.