Global Phylogeography and Genomic Characterization of Vibrio Parahaemolyticus Infections in Jilin Province, China (2016–2022)

Abstract

Vibrio parahaemolyticus is a critical foodborne pathogen causing gastroenteritis worldwide. Furthermore, the incidence of transmission and outbreaks attributed to V. parahaemolyticus has exhibited a notable upward trend during the past two decades. However, comprehensive information of this pathogen in inland cities in China remains scarce. This study encompassed molecular characteristics, genetic associations, and transmission of 115 V. parahaemolyticus strains obtained from nine inland cities in Jilin Province. The strain was divided into 90 sequence types (STs), with 41 STs were novel. And predominant sequence type was ST3 (14.78%, 17/115). The strains presented the highest resistance rate against cefazolin and ampicillin. Ninety-four antibiotic resistance genes (ARGs) divided into 8 categories of antibiotics were identified. Tet(34) (112/115, 97.39%) and bla-CARB (114/115, 99.13%) gene responsible for tetracycline and β-lactams resistance were present in most isolates. Interestingly, V. parahaemolyticus with detected tet(34) gene may not necessarily be resistant to tetracycline, and vice versa. And strains with strong biofilm formation ability possess more resistance genes. The atypical virulence genes and virulence genome islands (VPaI) of the isolated strains were also identified. All strains encode type III secretion system 1 (T3SS1), while 114 isolates encode type VI secretion system 2 (T6SS2). Important to note was that T6SS1 was encoded in 59.55% of food strains. Based on the distribution of VPaI related fragments, the pathogenicity genomic islands VPaI-1-5 were found in food-associated isolates, while clinical strains were closely related within a single cluster, and the food isolates were relatively highly diverse. Furthermore, some isolates included in our research indicated the potential transmission, sharing some SNPs between food and clinical-positive V. parahaemolyticus strains in different countries. Our research expands the perspective on the genetic characteristic, diversity, and virulence potential of V. parahaemolyticus isolates, which helps to better understand the potential risks of cross-border transmission of the pathogen.

Keywords: Vibrio parahaemolyticus, Genetic diversity, antibiotic resistance, virulence, Multilocus sequence typing, WgSNP