AUTHOR=Yu Yongxiang , Liu Xiao , Wang Yingeng , Liao Meijie , Tang Miaomiao , Rong Xiaojun , Wang Chunyuan , Li Bin , Zhang Zheng 

TITLE=Antimicrobial Resistance and Genotype Characteristics of Vibrio scophthalmi Isolated from Diseased Mariculture Fish Intestines With Typical Inter-Annual Variability

JOURNAL=Frontiers in Marine Science

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.924130

DOI=10.3389/fmars.2022.924130

ISSN=2296-7745

ABSTRACT=<p>As an intestinal organism settled long-term within the gut of marine fish, Vibrio scophthalmi is a potential object for the bacterium genetic variation and adaptation research. The genetic diversity, antimicrobial resistance phenotype, and genotype of 33 V. <italic>scophthalmi</italic> isolated from diseased marine fish intestines between 2002 and 2020 were evaluated. The results showed that all isolates were frequently resistant to penicillins, cephalosporins, aminoglycosides, and macrolides and displayed multidrug-resistant (MDR) phenotype <italic>in vitro</italic>. Thirty percent of isolates were resistant to more than 20 different drugs. The average insensitive (resistant and intermediate) rate of <italic>V. scophthalmi</italic> isolates was 49.5%~81.8% between 2002 and 2020, but the t-test revealed that there was no significant difference in the drug-resistance rate of <italic>V. scophthalmi</italic> isolates with typical interannual variability. Eleven antimicrobial resistance genes (<italic>strB</italic>, <italic>strA</italic>, <italic>ant(3 ˝)-I</italic>, <italic>mphA</italic>, <italic>blaPSE</italic>, <italic>qnrS</italic>, <italic>tetC</italic>, <italic>tetE</italic>, <italic>tetM</italic>, <italic>tetS</italic>, and <italic>int1</italic>) were detected in these isolates, but the antimicrobial resistance phenotypes and genotypes of these isolates were not consistent. Enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) analysis indicated that 33 isolates could be divided into two clusters (G1 and G3) and two single isolates (G2 and G4), and the G2 cluster was isolated from South Sea <italic>C. undulates</italic> with typical geographical species differences. There was no significant correlation between the drug susceptibility and the genetic types of <italic>V. scophthalmi</italic> isolates. The results reveal the mismatch phenomenon between antimicrobial resistance and genotype of inherent <italic>V. scophthalmi</italic> in the marine fish intestines, and the antimicrobial susceptibility isolates might be a potential risk source for storage and transmission of resistance genes.</p>