Flavobacterium psychrophilum in Baltic salmon Salmo salar brood fish and their offspring

Ekman, Elisabet; Börjeson, Hans; Johansson, Nils

doi:10.3354/dao037159

Cited by 50 publications

(45 citation statements)

References 11 publications

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“…F. psychrophilum outbreaks were first described in North America from Coho salmon Oncorhynchus kisutch (Borg 1948); the disease was then also identified in France, Germany, the UK, Finland, Denmark, Norway, and Switzerland as well as in Asian countries such as Japan and Korea, reported in ayu Plecoglossus altivelis (Nematollahi et al 2003, Barnes & Brown 2011. Although the role of the commercial fish and egg trade in the dissemination of the pathogen has yet to be clarified, F. psychrophilum infections in salmonid fish farms can now be considered cosmopolitan (Bernardet & Kerouault 1989, Cipriano et al 1995, Ekman et al 1999.…”

Section: Introductionmentioning

confidence: 99%

Molecular epidemiology of Flavobacterium psychrophilum from Swiss fish farms

Strepparava¹,

Nicolas²,

Wahli³

et al. 2013

Dis. Aquat. Org.

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Bacterial cold water disease (BCWD) and rainbow trout fry syndrome (RTFS) caused by Flavobacterium psychrophilum are 2 of the major diseases causing high fish mortality in salmonid fish farms. The molecular epidemiology of F. psychrophilum is still largely unknown. Multilocus sequence typing (MLST) has been previously used for this pathogen and underscored a correlation between clonal complexes and host fish species. Here we used MLST to study the relationships among 112 F. psychrophilum isolates from rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta fario and S. t. lacustris in Swiss fish farms between 1993 and 2012. The isolates belonged to 27 different sequence types (STs). Most of the Swiss outbreaks were associated with strains belonging to clonal complexes CC-ST2 and CC-ST90, found in both rainbow trout and brown trout and represented by several STs. Eight ST singletons could not be connected to any known clonal complex. Already reported from other parts of Europe and North America, CC-ST2 was the most frequent clonal complex observed, and it caused the majority of outbreaks in Switzerland, with CC-ST90 being the second most important type. In the tightly interconnected Swiss fish farms, no association between clonal complex and host fish was detected, but a temporal evolution of the frequency of some STs was observed. The occurrence of sporadic STs suggests high F. psychrophilum diversity and may reflect the presence of different sequence types in the environment. KEY WORDS: F. psychrophilum · BCWD · RTFS · Myxobacteria · Pathology · Clonal complex · Sequence complex · Allele type · MLST · FlavobacteriosisResale or republication not permitted without written consent of the publisher Dis Aquat Org 105: 203-210, 2013 ent methods such as serotyping, ribotyping, and plasmid profiling (Madetoja et al. 2002, Hesami et al. 2008, Kim et al. 2010. Multilocus sequence typing (MLST) allows the characterization of bacteria based on the nucleotide sequences of several housekeeping genes. Each fragment represents an allele type (AT), and each combination of alleles allows assigning each isolate to a sequence type (ST). This approach is highly reproducible and standardized, as it depends directly on DNA sequences (Maiden et al. 1998). While MLST has also been used to identify species, for instance in the genera Aeromonas (Martino et al. 2011) and Wolbachia (Baldo et al. 2006), its main use is linked to epidemiological investigations. It has been used to study the epidemiology of selected pathogenic bacterial species such as community and healthcare-associated strains of multidrug resistant Staphylococcus aureus (MRSA;Peterson et al. 2012) and animal pathogenic strains of Brachyspira hydysenteriae among farmed and wild pigs in Spain and other countries (Osorio et al. 2012). In aquaculture, this technique has been used to type isolates of the fish pathogen Yersinia ruckeri from different geographical areas, different hosts, and different environments (Bastardo et al. 2012). Nicolas et al. (2008) ...

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Section: Introductionmentioning

confidence: 99%

Molecular epidemiology of Flavobacterium psychrophilum from Swiss fish farms

Strepparava¹,

Nicolas²,

Wahli³

et al. 2013

Dis. Aquat. Org.

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“…The bacterium causing bacterial kidney disease (BKD), Renibacterium salmoninarum, has been shown to be vertically transmitted (Evelyn et al 1984), and Flavobacterium psychrophilum has been isolated from the inside of the fertilised egg (Brown et al 1997, Kumagai et al 2000, as well as from internal organs and sexual products of brood fish (Holt et al 1987, Rangdale et al 1996, Brown et al 1997, Ekman et al 1999, indicating vertical transmission.…”

Section: Abstract: Flavobacterium Psychrophilum · Nanoinjection · Rtmentioning

confidence: 99%

Nanoinjection as a tool to mimic vertical transmission of Flavobacterium psychrophilum in rainbow trout Oncorhynchus mykiss

Ekman

Åkerman²,

Balk³

et al. 2003

Dis. Aquat. Org.

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“…BCWD is primarily a disease of salmonids although other commercially important fish species can be affected (Iguchi et al 2003, Nematollahi et al 2003. BCWD -or RTFS -can have severe impacts on aquaculture and there have been reports of this diseases worldwide (Bernardet et al 1988, Wakabayashi et al 1991, Toranzo & Barja 1993, Wiklund et al 1994, Bustos et al 1995, Ekman et al 1999. At present there is no commercial vaccine available and the primary prevention strategy is careful population management (e.g.…”

Section: Introductionmentioning

confidence: 99%

Polymorphisms in 16S rRNA genes of Flavobacterium psychrophilum correlate with elastin hydrolysis and tetracycline resistance

Soule¹,

LaFrentz²,

Cain³

et al. 2005

Dis. Aquat. Org.

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Flavobacterium psychrophilum is the etiological agent of bacterial coldwater disease, which causes significant problems to aquaculture worldwide. A recent study (Soule M, Cain K, LaFrentz S, Call DR [2005] Infect Immun 73:3799-3802) identified two 16S rRNA gene sequence variants (6 base differences) within the variable stem-loop region 3 for F. psychrophilum strains ATCC 49418 and CSF 259-93. That study also hypothesized that F. psychrophilum is composed of at least 2 distinct genetic lineages (I and II) described by a microarray-based comparative genomics study. In the present study, we augmented an existing 16S rDNA microarray to detect both 16S rRNA sequence variants from F. psychrophilum. Subsequent microarray experiments showed that CSF 259-93 hybridized as expected, but ATCC 49418 was positive for both sequence variants. We then developed a PCR-restriction fragment length polymorphism (RFLP) assay (MnlI and MaeIII) to distinguish between the 2 sequences. Gel isolation of PCR-RFLP products, cloning, and sequencing confirmed that ATCC 49418 harbors both 16S rRNA sequences. Microarray experiments showed that 11 of 14 strains from genetic Lineage I harbor both the CSF 259-93 and ATCC 49418 16S rRNA sequence variants, whereas all 15 Lineage II strains were only positive for the CSF 259-93 sequence (p < 0.0001). Elastin hydrolysis and tetracycline resistance were most closely associated with the latter strains (p < 0.0001 and p = 0.024, respectively). These data support the hypothesis that F. psychrophilum is composed of at least 2 distinct genetic lineages that are closely associated with host origin. KEY WORDS: 16S rRNA · Flavobacterium psychrophilum · Bacterial coldwater disease · Elastin hydrolysis · Microarray hybridization · Tetracycline resistance Resale or republication not permitted without written consent of the publisherDis Aquat Org 65: [209][210][211][212][213][214][215][216] 2005 In general, Flavobacterium psychrophilum strains are biochemically homogeneous, with the exception of some variation in the presence or absence of caseinases, gelatinases, and elastases (Bertolini et al. 1994, Lorenzen et al. 1997, Madetoja et al. 2001. Not all strains of F. psychrophilum are capable of causing the same degree of disease (Holt 1987, Madetoja et al. 2002, LaFrentz et al. 2003 and they can be antigenically diverse (Evensen & Lorenzen 1996, Crump et al. 2001, Madetoja et al. 2002. Immunization with killed cells of one strain does not necessarily convey protective immunity from infection by other strains (Holt et al. 1989, Obach & Laurencin 1991.Genetic variation has been assessed between strains using ribotyping, plasmid profiles, randomly amplified polymorphic DNA (RAPD), and PCR-RFLP of specific gene fragments (Chakroun et al. 1997, Chakroun et al. 1998, Madetoja et al. 2001, Izumi et al. 2003. Studies of outbreak strains from Danish trout farms suggest dominance by a single ribotype , Madetoja et al. 2002, but other studies show greater genetic variation across geographic scales (Chakroun et a...

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Flavobacterium psychrophilum in Baltic salmon Salmo salar brood fish and their offspring

Cited by 50 publications

References 11 publications

Molecular epidemiology of Flavobacterium psychrophilum from Swiss fish farms

Molecular epidemiology of Flavobacterium psychrophilum from Swiss fish farms

Nanoinjection as a tool to mimic vertical transmission of Flavobacterium psychrophilum in rainbow trout Oncorhynchus mykiss

Polymorphisms in 16S rRNA genes of Flavobacterium psychrophilum correlate with elastin hydrolysis and tetracycline resistance

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