Rapid multiplex polymerase chain reaction for simultaneous detection of Vibrio harveyi, V. parahaemolyticus, and V. vulnificus in pacific white shrimp (Litopenaeus vannamei)

Context: A comparatively small number of species, e.g., Vibrio parahaemolyticus and V. vulnificus, cause disease in both aquatic animals and humans. V. harveyi is marine animal pathogen and rarely causes infections in humans; however, it might become a reservoir of antibiotic-resistant bacteria forms and virulence genes. Aims: 1) to develop rapid multiplex polymerase chain reaction (PCR) assay for the simultaneous detection of V. harveyi, V. parahaemolyticus, and V. vulnificus by using vhhP2, tl, and rpoS genes as the respective target genes and 2) to evaluate specificity and determined detection of multiplex PCR technique. Materials and Methods: The multiplex PCR assay was developed and evaluated for specificity on 36 isolates of V. harveyi, 30 isolates of V. parahaemolyticus, and 14 isolates of V. vulnificus, along with other species of Vibrio and non-Vibrio bacterial isolates. Sensitivity of test was described as detection limit of pathogens in lowest amount of sample (CFU/mL or CFU/g) was determined by diluted DNA extracts of the pure cultures and spiked pacific white shrimp (Litopenaeus vannamei) samples Results: This developed multiplex PCR was proved as an accurate method, which was specific for three Vibrio species. The detection limits of V. harveyi, V. parahaemolyticus, and V. vulnificus in pure cultures and spiked shrimp samples ranged 1.05-4.8 x 10(3) CFU/mL and 1.9-7 x 10(4) CFU/g, respectively. Conclusions: This rapid multiplex PCR assay can decrease amount and process of sample preparation, which was time-consuming, and had preferable accuracy. This developed technique will be suitable and useful for food-borne pathogen detection in shrimp and horizontal gene transfer study among different Vibrio species in aquatic animals.