Complete genome analysis of Vibrio mimicus strain SCCF01, a highly virulent isolate from the freshwater catfish

Zehui Yu,Erlong Wang,Yi Geng,Kaiyu Wang,Defang Chen,Xiaoli Huang,Ping Ouyang,Zhicai Zuo,Chao Huang,Jing Fang,Lizi Yin,Hongrui Guo,Zhijun Zhong

doi:10.1080/21505594.2019.1702797

Abstract

ABSTRACT Vibrio mimicus is a foodborne pathogen, which is widely distributed in the aquatic environment. Moreover, it is often involved in aquatic animal diseases. In recent years, V. mimicus is an emerging pathogen in some species of Siluriformes. The strain SCCF01 was isolated from yellow catfish (Pelteobagrus fulvidraco). In this study, we aimed to perform genomic analysis of V. mimicus strain SCCF01 to identify genetic features and evolutionary relationships. Information on gene function and classification was obtained by functional annotation, and circular graph of strain SCCF01 genome, which was created by Circos v0.64. Information on virulence genes (adhesion, flagellum system, exotoxin, and secretory system, etc.) was obtained by virulence genes annotation. Genome element prediction showed that most of the mobile elements were distributed in chromosome I. Therefore, chromosome I of SCCF01 genome has more plasticity than chromosome II and might be larger in size. Genomic linear relationship between the strain of V. mimicus and strain SCCF01 was analyzed by linear pairwise comparison but was unable to determine the relationship. Gene family analysis predicted that the evolutionary direction of strain SCCF01 was: clinical strain → environmental strain → SCCF01 strain. Phylogenetic analysis showed that the strain SCCF01 was more closely related to environmental strains. According to gene family analysis and phylogenetic analysis, we speculated that strain SCCF01 has probably diverged from environmental strains.

Highlights

Vibrio mimicus (V. mimicus) was initially considered as an atypical V. cholerae,[1] which is closely related to Vibrio cholerae
V. mimicus strain SCCF01, which is a highly virulent strain isolated from yellow catfish (Pelteobagrus fulvidraco) in China, causes almost 100% mortality in yellow catfish [9,12]
V. mimicus strain SCCF01, which was isolated from diseased yellow catfish (Pelteobagrus fulvidraco) at a commercial aquaculture site in Southwest China [9]

Summary

Introduction

Vibrio mimicus (V. mimicus) was initially considered as an atypical V. cholerae,[1] which is closely related to Vibrio cholerae. V. mimicus is a widely distributed aquatic bacterium that can cause disease in humans and massive death of aquatic animals. It is a foodborne pathogen [2], which can cause gastroenteritis, diarrhea and food poisoning [3,4,5]. The epidemiological features of V. mimicus showed short disease duration and high mortality rate, which eventually leads to substantial economic loss in Siluriformes farmhouses [9,10]. V. mimicus strain SCCF01, which is a highly virulent strain isolated from yellow catfish (Pelteobagrus fulvidraco) in China, causes almost 100% mortality in yellow catfish [9,12]

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