De Novo Sequencing Provides Insights Into the Pathogenicity of Foodborne Vibrio parahaemolyticus.

Jianfei Liu,Lijun Zhou,Kaifei Fu,Chenglin Wu,Kewei Qin,Xiaojie Yu

doi:10.3389/fcimb.2021.652957

Abstract

Vibrio parahaemolyticus is a common pathogenic marine bacterium that causes gastrointestinal infections and other health complications, which could be life-threatening to immunocompromised patients. For the past two decades, the pathogenicity of environmental V. parahaemolyticus has increased greatly, and the genomic change behind this phenomenon still needs an in-depth exploration. To investigate the difference in pathogenicity at the genomic level, three strains with different hemolysin expression and biofilm formation capacity were screened out of 69 environmental V. parahaemolyticus strains. Subsequently, 16S rDNA analysis, de novo sequencing, pathogenicity test, and antibiotic resistance assays were performed. Comparative genome-scale interpretation showed that various functional region differences in pathogenicity of the selected V. parahaemolyticus strains were due to dissimilarities in the distribution of key genetic elements and in the secretory system compositions. Furthermore, the genomic analysis-based hypothesis of distinct pathogenic effects was verified by the survival rate of mouse models infected with different V. parahaemolyticus strains. Antibiotic resistance results also presented the multi-directional evolutionary potential in environmental V. parahaemolyticus, in agreement with the phylogenetic analysis results. Our study provides a theoretical basis for better understanding of the increasing pathogenicity of environmental V. parahaemolyticus at the genome level. Further, it has a key referential value for the exploration of pathogenicity and prevention of environmental V. parahaemolyticus in the future.

Highlights

Vibrio parahaemolyticus is a gram-negative halophilic bacterial species, first identified in 1950 (Fujino et al, 1953)
There has been an increase in the number of clinical cases of V. parahaemolyticus infection (Li et al, 2016), and sporadic or epidemic cases have been reported in some regions that were once considered unsuitable for the growth of V. parahaemolyticus, such as South America and Northern Europe (Martinez-Urtaza et al, 2010; Baker-Austin et al, 2013)
Due to the increasing global incidence of foodborne gastroenteritis caused by V. parahaemolyticus (Rezny and Evans, 2020), it is imperative to reevaluate the pathogenicity of this bacteria using modern tools

Summary

Introduction

Vibrio parahaemolyticus is a gram-negative halophilic bacterial species, first identified in 1950 (Fujino et al, 1953). There has been an increase in the number of clinical cases of V. parahaemolyticus infection (Li et al, 2016), and sporadic or epidemic cases have been reported in some regions that were once considered unsuitable for the growth of V. parahaemolyticus, such as South America and Northern Europe (Martinez-Urtaza et al, 2010; Baker-Austin et al, 2013). This suggests that V. parahaemolyticus is continuously evolving and is developing into a more serious pathogen (Nair et al, 2007; Newton et al, 2014). The mechanisms of its rapid serotype conversion and pandemic evolution have not been revealed yet

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