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Multilocus sequence typing (MLST) analysis of California Flavobacterium psychrophilum reveals novel genotypes and predominance of CC‐ST10 in California salmonid hatcheries
Author(s) -
Sebastião Fernanda de Alexandre,
Loch Thomas P.,
Knupp Christopher,
Mukkatira Kaveramma,
Veek Tresa,
Richey Christine,
Adkison Mark,
Griffin Matt J.,
Soto Esteban
Publication year - 2020
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/are.14578
Subject(s) - biology , multilocus sequence typing , outbreak , rainbow trout , pathogen , genotype , epizootiology , genetic diversity , microbiology and biotechnology , virology , genetics , fishery , gene , population , demography , sociology , fish <actinopterygii>
The Gram‐negative bacterium, Flavobacterium psychrophilum, is endemic to California, USA, where it is an important pathogen in salmonid aquaculture, especially in rainbow trout ( Oncorhynchus mykiss ). Disease outbreaks caused by F. psychrophilum in rainbow trout fingerlings can approach 90% mortality, resulting in millions of dollars of economic losses annually. The focus of this study was to investigate the genetic diversity of 49 F. psychrophilum isolates collected from disease outbreaks in 17 salmonid hatcheries in California, USA, from 2015 to 2018 using multilocus sequence typing. Results suggest California F. psychrophilum isolates are diverse, representing 11 distinct sequence types (STs), three of which were previously undescribed. Still, the majority of genotyped isolates ( n = 41) belonged to a single clonal complex (CC), CC‐ST10, which is the largest CC worldwide and has been linked to disease outbreaks on several continents. Results of this study provide evidence of marked intraspecific genetic diversity of F. psychrophilum from California . The biological significance of this genetic variability is unclear but could have implications for future vaccine development and treatments. Further studies investigating the virulence, antigenic, and antimicrobial susceptibility profiles of F. psychrophilum are warranted to better understand the epizootiology of this pathogen in the Western United States.