Introduction of Yersinia ruckeri biotype 2 into Finnish fish farms

Ström-Bestor, Maria; Mustamäki, Noora; Heinikainen, Sirpa; Hirvelä-Koski, Varpu; Verner–Jeffreys, David W.; Wıklund, Tom

doi:10.1016/j.aquaculture.2010.08.009

Cited by 24 publications

(28 citation statements)

References 20 publications

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“…We have previously shown that a defined mutation in flhA, which encodes a critical component of the flagellar secretion apparatus, mimicked the BT2 phenotype and had no discernible effect on virulence in a motile BT1 strain when using a natural infection route and an immunologically naive host (13). Loss of motility and lipase secretion also has not affected the success of natural BT2 strains, as evidenced by the recent reports of BT2-caused disease outbreaks and laboratory virulence testing of BT2 strains (3,4,15,36,41). While these results suggest that mutational loss of flagellar secretion can be tolerated by this pathogen with no measurable effect on virulence, currently there is no evidence that loss of flagellar secretion provides a selective advantage in avoiding the immune response.…”

Section: Discussionmentioning

confidence: 76%

“…BT2 Y. ruckeri was recognized in the United Kingdom prior to 1989, with the earliest strains isolated in 1981 (11), while in Spain, Denmark, and Finland, BT2 strains have been identified more recently (15,36,42). Moreover, pulsed-field gel electrophoresis (PFGE) analysis established that the BT2 strains in Denmark and Spain are more closely related to the BT1 strains present in these countries than to BT2 strains from the United Kingdom, thus suggesting that the BT2 phenotype has arisen independently in mainland Europe from local BT1 strains (42).…”

Section: Discussionmentioning

confidence: 99%

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Independent Emergence of Yersinia ruckeri Biotype 2 in the United States and Europe

Welch

Verner–Jeffreys

Dalsgaard

et al. 2011

Appl Environ Microbiol

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Biotype 2 (BT2) variants of the bacterium Yersinia ruckeri are an increasing disease problem in U.S. and European aquaculture and have been characterized as serovar 1 isolates that lack both peritrichous flagella and secreted phospholipase activity. The emergence of this biotype has been associated with an increased frequency of enteric redmouth disease (ERM) outbreaks in previously vaccinated salmonid fish. In this study, four independent specific natural mutations that cause the loss of both motility and secreted lipase activity were identified in BT2 strains from the United States, United Kingdom, and mainland Europe. Each of these was a unique mutation in either fliR, flhA, or flhB, all of which are genes predicted to encode essential components of the flagellar secretion apparatus. Our results demonstrate the existence of independent mutations leading to the BT2 phenotype; thus, this phenotype has emerged separately at least four times. In addition, BT2 strains from the United Kingdom were shown to have the same mutant allele found in U.S. BT2 strains, suggesting a common origin of this BT2 lineage. This differentiation of distinct BT2 lineages is of critical importance for the development and validation of alternative vaccines or other treatment strategies intended for the control of BT2 strains.

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Section: Discussionmentioning

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Independent Emergence of Yersinia ruckeri Biotype 2 in the United States and Europe

Welch

Verner–Jeffreys

Dalsgaard

et al. 2011

Appl Environ Microbiol

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“…These outbreaks have often been linked to the presence of non-motile isolates (assigned as biotype 2, BT 2, isolates). Non-motile BT 2 isolates were found in trout populations in the UK, the European mainland (Austin et al 2003, Fouz et al 2006, Ström-Bestor et al 2010 and North America (Arias et al 2007). The first isolation from a trout population in Germany dates back to 1994 (Klein et al 1994).…”

Section: Introductionmentioning

confidence: 99%

Analysis of Yersinia ruckeri strains isolated from trout farms in northwest Germany

Huang¹,

Jung²,

Schäfer³

et al. 2015

Dis. Aquat. Org.

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Enteric redmouth disease (ERM), caused by Yersinia ruckeri, is among the most important infectious diseases in rainbow trout Oncorhynchus mykiss aquaculture in Europe. Our aim was to analyse the persistence of Y. ruckeri strains in trout farms in northwest Germany and their dissemination between farms based on a detailed molecular and phenotypical characterisation scheme. The data on identification and characterisation of Y. ruckeri strains and examining the distribution of these strains in the field could serve as a basis for preventive disease monitoring plans. During the observation period from June 2011 until June 2012, we collected 48 Y. ruckeri isolates from 12 different rainbow trout hatcheries. In total, 44 (91.7%) of the isolates were nonmotile; in particular, all isolates recovered during the sampling period in winter and early spring were non-motile. In several trout farms, characteristic farm-specific Y. ruckeri isolates from particular typing groups were isolated throughout the year, while in other farms, which had a trading relationship between each other, ERM outbreaks were caused by Y. ruckeri from the same typing group. Our data indicate that in some farms, the causative Y. ruckeri strains persisted in the respective trout farm. The presence of Y. ruckeri from the same typing group in farms with a trading relationship indicates a dissemination of the infection between the farms. KEY WORDS: Epidemiology · Enteric redmouth disease · Rainbow trout · Oncorhynchus mykissResale or republication not permitted without written consent of the publisher FREE REE ACCESS CCESS

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“…Serotyping is particularly important for strain differentiation of Y. ruckeri, and the O-serotyping scheme of Davies (14) is the most commonly used (12,(15)(16)(17). In this scheme, five O serotypes, O1, O2, O5, O6, and O7, are recognized by rapid slide agglutination assay using defined O antigens (14); the individual O serotypes correspond to discrete lipopolysaccharide (LPS) types as identified by SDS-PAGE and Western blotting (18).…”

mentioning

confidence: 99%

“…Since the first identification of biotype 2 isolates in the United Kingdom, nonmotile variants have been described elsewhere in Europe (16,17,(23)(24)(25), the United States (26), and Australia (7). Indeed, biotype 2 Y. ruckeri strains are causing increasing concern because they are responsible for disease in fish previously vaccinated against biotype 1 strains (17,20,23,26,27). A typing scheme based on the molecular mass variation of the major outer membrane proteins (OMPs) was developed to further differentiate between strains of Y. ruckeri (28).…”

mentioning

confidence: 99%

Yersinia ruckeri Isolates Recovered from Diseased Atlantic Salmon (Salmo salar) in Scotland Are More Diverse than Those from Rainbow Trout (Oncorhynchus mykiss) and Represent Distinct Subpopulations

Ormsby

Caws

Burchmore

et al. 2016

Appl Environ Microbiol

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Yersinia ruckeri is the etiological agent of enteric redmouth (ERM) disease of farmed salmonids. Enteric redmouth disease is traditionally associated with rainbow trout (Oncorhynchus mykiss, Walbaum), but its incidence in Atlantic salmon (Salmo salar) is increasing. Yersinia ruckeri isolates recovered from diseased Atlantic salmon have been poorly characterized, and very little is known about the relationship of the isolates associated with these two species. Phenotypic approaches were used to characterize 109 Y. ruckeri isolates recovered over a 14-year period from infected Atlantic salmon in Scotland; 26 isolates from infected rainbow trout were also characterized. Biotyping, serotyping, and comparison of outer membrane protein profiles identified 19 Y. ruckeri clones associated with Atlantic salmon but only five associated with rainbow trout; none of the Atlantic salmon clones occurred in rainbow trout and vice versa. These findings suggest that distinct subpopulations of Y. ruckeri are associated with each species. A new O serotype (designated O8) was identified in 56 biotype 1 Atlantic salmon isolates and was the most common serotype identified from 2006 to 2011 and in 2014, suggesting an increased prevalence during the time period sampled. Rainbow trout isolates were represented almost exclusively by the same biotype 2, serotype O1 clone that has been responsible for the majority of ERM outbreaks in this species within the United Kingdom since the 1980s. However, the identification of two biotype 2, serotype O8 isolates in rainbow trout suggests that vaccines containing serotypes O1 and O8 should be evaluated in both rainbow trout and Atlantic salmon for application in Scotland. IMPORTANCEVaccination plays an important role in protecting Atlantic salmon against the bacterial pathogen Yersinia ruckeri, but, in recent years, there has been an increasing incidence of vaccine breakdown in salmon. This is largely because current vaccines are aimed at rainbow trout and are based on serotypes specific for this species. A wider range of serotypes is responsible for infection in Atlantic salmon, but very little is known about the diversity of these strains and their relationships to those recovered from rainbow trout. In the present study, we demonstrate that Y. ruckeri isolates recovered from diseased Atlantic salmon in Scotland are more diverse than those from rainbow trout; furthermore, isolates from the two species represent distinct subpopulations. In addition, a new O serotype was identified that is responsible for a significant proportion of the disease in Atlantic salmon. Our findings are likely to have important implications for the development of improved vaccines against Y. ruckeri. The Gram-negative bacterium Yersinia ruckeri is the etiological agent of enteric redmouth (ERM) disease of cultured salmonids and causes significant economic losses to the fish-farming industry. Yersinia ruckeri was first isolated in 1956 from diseased rainbow trout (Oncorhynchus mykiss, Walbaum) in the Hagerman Valle...

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Introduction of Yersinia ruckeri biotype 2 into Finnish fish farms

Cited by 24 publications

References 20 publications

Independent Emergence of Yersinia ruckeri Biotype 2 in the United States and Europe

Independent Emergence of Yersinia ruckeri Biotype 2 in the United States and Europe

Analysis of Yersinia ruckeri strains isolated from trout farms in northwest Germany

Yersinia ruckeri Isolates Recovered from Diseased Atlantic Salmon (Salmo salar) in Scotland Are More Diverse than Those from Rainbow Trout (Oncorhynchus mykiss) and Represent Distinct Subpopulations

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