AUTHOR=Zhu Qiaoyun , Chen Xiao , Liu Yanchao , Wang Ruonan , Chen Jiayao , Chen Yu 

TITLE=Virulence, Antimicrobial Susceptibility, Molecular and Epidemiological Characteristics of a New Serotype of Vibrio parahaemolyticus From Diarrhea Patients

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.02025

DOI=10.3389/fmicb.2020.02025

ISSN=1664-302X

ABSTRACT=<p><italic>Vibrio parahaemolyticus</italic> is the main pathogen of food-borne diarrheal in coastal areas. Through the study of pathogen characteristics of 1870 <italic>V. parahaemolyticus</italic>, the isolation rate of O4:KUT had increased significantly since 2013. In this study, we analyzed virulence, antimicrobial susceptibility, molecular, and epidemiological characteristics of a new serotype named O4:KUT2. O4:KUT2 strains had <italic>tlh</italic><sup>+</sup><italic>tdh</italic><sup>+</sup><italic>trh</italic><sup>–</sup><italic>toxRS/</italic>new<sup>–</sup> characteristics and were prevalent during 2013–2015. The 91.5% O4:KUT2 serotype strains were resistant to ampicillin. The growth curves of O4:KUT2 strains were different with O4:K9, O4:K8, and O3:K6 serotype strains. O4:KUT2 strains belonged to ST332 where four strains had a large fragment inserted at <italic>recA</italic>. Compared the whole genomes of O4:KUT2 strains with O4:K9 strain which also belonged to ST322 isolated from acute diarrhea patients in Zhejiang province in 2012, no different alleles at 2249 loci was found. This finding implied that O4:KUT2 strains might be derived from O4:K9 strains. Clinical presentation of patients positive for <italic>V. parahaemolyticus</italic> O4:KUT2 were no significant difference with patients positive for O3:K6, although their genetic characteristics were different. The appearance and the increase of proportion of the new serotype O4:KUT2 strains was aware that we should not relax the monitoring of the pathogen spectrum of acute diarrheal patients.</p>