Prevalence of Vibrio parahaemolyticus Isolated from Aquaculture Products in Farming Environment in Zhangzhou City

In order to investigate the prevalence and gene polymorphism of Vibrio parahaemolyticus in the farming environment of Zhangzhou city, fresh samples of Oreochroms mossambcus, Epinephelus spp. and Penaeus vannamei were collected from 7 farms in this region from January to July in 2019. The suspected isolates were cultured and purified by thiosulfate citrate bile salts sucrose agar culture medium (TCBS). The fragments of tlh gene and 16S rDNA gene were amplified by PCR and sequenced to identify the suspected strains. The genotyping of Vibrio parahaemolytic isolates was performed by random amplified polymorphic DNA (RAPD) method. A total of 228 samples were collected in the experiment, and 111 suspected strains were obtained through microbiological screening. A total of 69 strains were identified as Vibrio parahaemolyticus by PCR and sequencing with a positive rate of 30.26%. RAPD technique was used to type isolates of Vibrio parahaemolyticus, and clearer DNA bands were obtained. Analysis of the fingerprints showed that 69 Vibrio parahaemolytic can be divided into 9 main types, with genetic similarity in the range of 83% to 100%. To some extent, the aquatic products in the farm will be contaminated by Vibrio parahaemolyticus, and the degree of contamination of Vibrio parahaemolyticus is variable in different aquatic products, different farms and at different times.