Prevalence of<i>Renibacterium salmoninarum</i>among DownstreamMigrating Salmonids in the Columbia River

Sanders, James E.; Long, J. J.; Arakawa, C. K.; Bartholomew, Jerri L.; Rohovec, J. S.

doi:10.1577/1548-8667(1992)004<0072:porsad>2.3.co;2

Cited by 35 publications

(26 citation statements)

References 7 publications

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“…Downstream migration and smoltification could exert a selective pressure against more heavily in fected or clinically ill fish. Juvenile salmon with BKD exhibit reduced survival when exposed to stressors simulating migration (Sanders et al 1992, Moles 1997 and while transitioning through smoltification (Mesa et al 1999). Clinically affected fish are also more susceptible to predation (Mesa et al 1998).…”

Section: Discussionmentioning

confidence: 99%

“…Efforts to control and reduce infection in hatcheries rely on antibiotic injections of broodstock and culling eggs from females with elevated levels of bacterial proteins in kidney tissue. Monitoring juvenile salmon during the freshwater phase has provided evidence that R. salmoninarum infection is endemic in Pacific Northwest watersheds (Sanders et al 1992, Pascho et al 1993, VanderKooi & Maule 1999, Arkoosh et al 2004. Less is known about the infection status in seawater (Meyers et al 1999, Bruno 2004, Rhodes et al 2006, especially during the early marine phase, a transition period between freshwater and ocean residence that is considered to be the most critical period in determining survival to adulthood (Pearcy 1992).…”

Section: Abstract: Chinook Salmon · Bacterial Infection · Risk Factomentioning

confidence: 99%

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Nearshore ecosystem predictors of a bacterial infection in juvenile Chinook salmon

Rhodes¹,

Rice²,

Greene³

et al. 2011

Mar. Ecol. Prog. Ser.

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Section: Discussionmentioning

confidence: 99%

Section: Abstract: Chinook Salmon · Bacterial Infection · Risk Factomentioning

confidence: 99%

Nearshore ecosystem predictors of a bacterial infection in juvenile Chinook salmon

Rhodes¹,

Rice²,

Greene³

et al. 2011

Mar. Ecol. Prog. Ser.

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“…Bacterial kidney disease (BKD) has been reported in most areas of the world where salmonid species are found (4,11,13,20,27,28,35,37,42,46), and it is a principal source of morbidity and mortality among cultured salmon and trout. Acute BKD is characterized by ascites, swollen kidneys, exophthalmia, melanosis, and granulomatous lesions of internal organs such as the kidney, whereas asymptomatic carriers can complete an entire life cycle and successfully spawn (16).…”

mentioning

confidence: 99%

Both msa Genes in Renibacterium salmoninarum Are Needed for Full Virulence in Bacterial Kidney Disease

Coady

Murray

Elliott

et al. 2006

Appl Environ Microbiol

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Renibacterium salmoninarum, a gram-positive diplococcobacillus that causes bacterial kidney disease among salmon and trout, has two chromosomal loci encoding the major soluble antigen (msa) gene. Because the MSA protein is widely suspected to be an important virulence factor, we used insertion-duplication mutagenesis to generate disruptions of either the msa1 or msa2 gene. Surprisingly, expression of MSA protein in broth cultures appeared unaffected. However, the virulence of either mutant in juvenile chinook salmon (Oncorhynchus tshawytscha) by intraperitoneal challenge was severely attenuated, suggesting that disruption of the msa1 or msa2 gene affected in vivo expression.Bacterial kidney disease (BKD) has been reported in most areas of the world where salmonid species are found (4,11,13,20,27,28,35,37,42,46), and it is a principal source of morbidity and mortality among cultured salmon and trout. Acute BKD is characterized by ascites, swollen kidneys, exophthalmia, melanosis, and granulomatous lesions of internal organs such as the kidney, whereas asymptomatic carriers can complete an entire life cycle and successfully spawn (16). The infectious agent of BKD, Renibacterium salmoninarum, can be transmitted both horizontally among cohorts and vertically by intraovum inclusion (2,14). Current disease controls include broodstock segregation or culling, antibiotic treatment, and vaccination, but these methods have only moderate efficacy in preventing or treating the disease (1,30,32).R. salmoninarum is a gram-positive diplococcobacillus that grows very slowly and has fastidious nutritional requirements (8,12,39,40). R. salmoninarum produces abundant quantities of an extracellular, 57-kDa protein called p57 or major soluble antigen (MSA) (7,17,41). MSA is associated with the bacterial surface and is released into surrounding tissues, and it has been associated with leukocyte agglutination (7, 43, 44) and immunomodulation (3, 15, 41, 45). A variant strain of R. salmoninarum displays both reduced MSA expression and lowered mortality upon infection (5, 24, 38), whereas R. salmoninarum isolates possessing an additional copy of the gene encoding MSA are more virulent than isolates lacking the additional copy (32). MSA is encoded by duplicate chromosomal loci (25), and both loci are expressed (33). These observations suggest that MSA is a significant virulence determinant, and we hypothesized that disruption of either chromosomal locus would result in a less virulent strain of R. salmoninarum. The goals of the present study were to generate and characterize R. salmoninarum clones bearing disruptions of either msa1 or msa2, to compare the production of MSA protein in the mutants and the parental R. salmoninarum strain, and to evaluate the virulence of the mutant and parental R. salmoninarum strains for chinook salmon, Oncorhynchus tshawytscha. MATERIALS AND METHODSBacterial strains, media, and culture conditions. The parental R. salmoninarum strain used for transformation was the ATCC type strain 33209 (American Type Cult...

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“…There have been a number of studies investigating the presence, prevalence, and means of transmission of BKD within and between fish populations. This work has shown that R. salmoninarum is endemic within many wild salmonid populations as a low-level, subclinical infection; it has been isolated in up to 100% of samples (9,12,15). However, the epidemiology of BKD remains unclear, mainly because of the difficulty of differentiating isolates of R. salmoninarum by biochemical, serological, and multilocus enzyme electrophoresis techniques (1,6,16).…”

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confidence: 99%

Molecular Diversity of Renibacterium salmoninarum Isolates Determined by Randomly Amplified Polymorphic DNA Analysis

Grayson¹,

Atienzar

Alexander³

et al. 2000

Appl Environ Microbiol

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The molecular diversity among 60 isolates of Renibacterium salmoninarum which differ in place and date of isolation was investigated by using randomly amplified polymorphic DNA (RAPD) analysis. Isolates were grouped into 21 banding patterns which did not reflect the biological source. Four 16S-23S rRNA intergenic spacer (ITS1) sequence variations and two alleles of an exact tandem repeat locus, ETR-A, were the bases for formation of distinct groups within the RAPD clusters. This study provides evidence that the most common ITS1 sequence variant, SV1, possesses two copies of a 51-bp repeat unit at ETR-A and has been widely dispersed among countries which are associated with mainstream intensive salmonid culture.Renibacterium salmoninarum is an important cause of clinical and subclinical infections among farmed and wild salmonid populations in North and South America, Europe, and Japan (5). The organism causes a chronic, systemic, and granulomatous infection, bacterial kidney disease (BKD), that is often fatal under conditions which are stressful to the host (11). There is no effective vaccine or chemotherapy, and the presence of subclinical infections complicates attempts to control the disease through programs of eradication. An improved understanding of the transmission and spread of BKD is of considerable importance in policy management issues relating to aquaculture and wildfisheries. There have been a number of studies investigating the presence, prevalence, and means of transmission of BKD within and between fish populations. This work has shown that R. salmoninarum is endemic within many wild salmonid populations as a low-level, subclinical infection; it has been isolated in up to 100% of samples (9,12,15). However, the epidemiology of BKD remains unclear, mainly because of the difficulty of differentiating isolates of R. salmoninarum by biochemical, serological, and multilocus enzyme electrophoresis techniques (1,6,16).We used two approaches to assess the extent of molecular variation among R. salmoninarum isolates from different geographic locations. First, we investigated possible polymorphisms in specific regions within the genome, genes msa (3), rsh (4), and hly (8), and the rRNA genes, including the intergenic spacer (ITS) regions. PCR and DNA sequencing studies have shown that R. salmoninarum has only limited variation in these regions (7). Identifying specific markers of variation in the R. salmoninarum genome, such as insertion sequences or variable numbers of tandem repeats (TR), has been constrained by a paucity of sequence information. Second, we analyzed differences throughout the genome using randomly amplified polymorphic DNA (RAPD) analysis. RAPD analysis is a PCR-based alternative method to the use of species-specific DNA sequences for isolate or strain differentiation. The method uses short random primers for rapidly detecting genomic polymorphisms under low-stringency conditions (18,19). RAPD analysis is widely used for differentiating bacterial isolates (2, 10, 17) and relies on small q...

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Prevalence ofRenibacterium salmoninarumamong DownstreamMigrating Salmonids in the Columbia River

Cited by 35 publications

References 7 publications

Nearshore ecosystem predictors of a bacterial infection in juvenile Chinook salmon

Nearshore ecosystem predictors of a bacterial infection in juvenile Chinook salmon

Both msa Genes in Renibacterium salmoninarum Are Needed for Full Virulence in Bacterial Kidney Disease

Molecular Diversity of Renibacterium salmoninarum Isolates Determined by Randomly Amplified Polymorphic DNA Analysis

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