title: Genetic and serological diversity of Flavobacterium psychrophilum isolates from salmonids in United Kingdom.
abstract: Flavobacterium psychrophilum is one of the most important bacterial pathogens affecting cultured rainbow trout (Oncorhynchus mykiss) and is increasingly causing problems in Atlantic salmon (Salmo salar L.) hatcheries. Little is known about the heterogeneity of F. psychrophilum isolates on UK salmonid farms. A total of 315 F. psychrophilum isolates, 293 of which were collected from 27 sites within the UK, were characterised using four genotyping methods and a serotyping scheme. A high strain diversity was identified among the isolates with 54 pulsotypes, ten (GTG)5-PCR types, two 16S rRNA allele lineages, seven plasmid profiles and three serotypes. Seven PFGE groups and 27 singletons were formed at a band similarity of 80%. PFGE group P (n=75) was found to be numerically predominant in eight sites within the UK. Two major PFGE clusters and 13 outliers were found at the band similarity of 40%. The predominant profileobserved within the F. psychrophilum isolates examined was PFGE cluster II - (GTG)5-PCR type r1-16S rRNA lineage II - serotype Th (70/156 isolates examined, 45%). Co-existence of genetically and serologically heterogeneous isolates within each farm was detected, confounding the ability to control RTFS outbreaks. The occurrence over time (up to 11 years) of F. psychrophilum pulsotypes in three representative sites (Scot I, Scot III and Scot V) within Scotland was examined, potentially providing important epidemiological data for farm management and the development of site-specific vaccines.
authors.affiliation: Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA, UK. Electronic address: tpn1@stir.ac.uk.
authors.forename: Thao P H
authors.initials: TPH
authors.lastname: Ngo
authors.affiliation: Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA, UK.
authors.forename: Kerry L
authors.initials: KL
authors.lastname: Bartie
authors.affiliation: Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA, UK; Moredun Research Institute, Pentlands Science Park, Penicuik, EH26 0PZ, UK.
authors.forename: Kim D
authors.initials: KD
authors.lastname: Thompson
authors.affiliation: The Centre for Environment, Fisheries and Aquaculture Science, The Nothe, Barrack Road, Weymouth, DT4 8UB, UK.
authors.forename: David W
authors.initials: DW
authors.lastname: Verner-Jeffreys
authors.affiliation: Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA, UK.
authors.forename: Rowena
authors.initials: R
authors.lastname: Hoare
authors.affiliation: Institute of Aquaculture, University of Stirling, Stirling, FK9 4LA, UK.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Adams
mesh_terms: D000483:Alleles; D000818:Animals; D004275:DNA, Ribosomal / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field / Q000662:veterinary; D005393:Fish Diseases / Q000453:epidemiology / Q000382:microbiology*; D045826:Flavobacteriaceae Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D005417:Flavobacterium / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D014644:Genetic Variation; D005838:Genotype; D017686:Oncorhynchus mykiss / Q000382:microbiology*; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000662:veterinary; D020317:Salmo salar / Q000382:microbiology*; D012606:Scotland / Q000453:epidemiology; D012703:Serotyping / Q000662:veterinary; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D004275:DNA, Ribosomal
keywords: Bacterial cold water disease; Flavobacterium psychrophilum; Genotyping; Plasmids; Rainbow trout fry syndrome; Serotyping