Mortality and pathology in brown bullheads Amieurus nebulosus associated with a spontaneous Edwardsiella ictaluri outbreak under tank culture conditions

Iwanowicz, Luke R.; Griffin, Alison R.; Cartwright, Deborah D.; Blazer, Vicki S.

doi:10.3354/dao070219

Cited by 27 publications

(23 citation statements)

References 20 publications

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“…The results showed that the fish challenged by immersion lived longer than those challenged by injection, and most of them showed similar clinical signs to injected fish. Clinical presentation of fish from the E. ictaluri experimental infection supported field observations of ESC in other fish species, as hole-in-thehead lesions and petechial haemorrhage of the skin have been reported in various fish species infected with E. ictaluri (Miyazaki & Plumb 1985;Iwanowicz et al 2006;Ye et al 2009;Liu et al 2010).…”

Section: Discussionsupporting

confidence: 66%

Mortality and pathology of hybrid catfish, Clarias macrocephalus (Günther) × Clarias gariepinus (Burchell), associated with Edwardsiella ictaluri infection in southern Thailand

Suanyuk

Rogge

Thune

et al. 2013

Journal of Fish Diseases

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Enteric septicaemia of catfish (ESC) caused by Edwardsiella ictaluri is becoming an increasing problem in aquaculture and has been reported worldwide in a variety of fish species. This study reports ESC in hybrid catfish, Clarias macrocephalus (Günther) × Clarias gariepinus (Burchell), cultured in southern Thailand. The bacteria were identified as E. ictaluri by conventional and rapid identification systems, as well as by genetic and phylogenetic characterization. Analysis of 16S rRNA indicated 100% homology to the 16S rRNA sequence of several E. ictaluri strains in GenBank. Plasmid profiles demonstrated 4.0- and 5.6-kb plasmids, compared with the 4.8- and 5.6-kb plasmids in the US isolates, and representative genes of three of the four known pathogenicity islands of US isolates were present. Serologically, lipopolysaccharide (LPS) purified from the Thai isolates was not recognized by a monoclonal antibody against the LPS of US isolates. Fish experimentally infected with E. ictaluri showed 23-100% mortality within 14 days with a 168-h LD50 of 6.92 × 10(7) CFU mL(-1) by immersion and a 96-h LD50 of 1.58 × 10(6) CFU fish(-1) by intraperitoneal injection. Examination of tissue sections obtained from both naturally and experimentally infected fish indicated that infection of hybrid catfish with E. ictaluri produced lesions in several organs including liver, kidney, spleen, heart and brain. Histopathology findings included cellular necrosis, focal haemorrhage, infiltration of lymphocytes and multifocal granulomatous inflammation in the infected organs.

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Section: Discussionsupporting

confidence: 66%

Mortality and pathology of hybrid catfish, Clarias macrocephalus (Günther) × Clarias gariepinus (Burchell), associated with Edwardsiella ictaluri infection in southern Thailand

Suanyuk

Rogge

Thune

et al. 2013

Journal of Fish Diseases

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“…The yggE gene (1.5-fold), conserved in Shigella flexneri and Edwardsiella ictaluri , encodes a putative extracellular protein. E. ictaluri is the causative agent of enteric septicemia of catfish [56], and yggE is considered a potential target antigen for vaccines for this disease [57]. Another gene, ytfK (4.9-fold), encodes a small protein (68 aa) whose function is not known, but is reported to be up-regulated when E. coli forms a biofilm [58].…”

Section: Resultsmentioning

confidence: 99%

Genome-Wide Analysis of the Pho Regulon in a pstCA Mutant of Citrobacter rodentium

et al. 2012

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The phosphate-specific transport operon, pstSCAB-phoU, of Gram-negative bacteria is an essential part of the Pho regulon. Its key roles are to encode a high-affinity inorganic phosphate transport system and to prevent activation of PhoB in phosphate-rich environments. In general, mutations in pstSCAB-phoU lead to the constitutive expression of the Pho regulon. Previously, we constructed a pstCA deletion mutant of Citrobacter rodentium and found it to be attenuated for virulence in mice, its natural host. This attenuation was dependent on PhoB or PhoB-regulated gene(s) because a phoB mutation restored virulence for mice to the pstCA mutant. To investigate how downstream genes may contribute to the virulence of C. rodentium, we used microarray analysis to investigate global gene expression of C. rodentium strain ICC169 and its isogenic pstCA mutant when grown in phosphate-rich medium. Overall 323 genes of the pstCA mutant were differentially expressed by at least 1.5-fold compared to the wild-type C. rodentium. Of these 145 were up-regulated and 178 were down-regulated. Differentially expressed genes included some involved in phosphate homoeostasis, cellular metabolism and protein metabolism. A large number of genes involved in stress responses and of unknown function were also differentially expressed, as were some virulence-associated genes. Up-regulated virulence-associated genes in the pstCA mutant included that for DegP, a serine protease, which appeared to be directly regulated by PhoB. Down-regulated genes included those for the production of the urease, flagella, NleG8 (a type III-secreted protein) and the tad focus (which encodes type IVb pili in Yersinia enterocolitica). Infection studies using C57/BL6 mice showed that DegP and NleG8 play a role in bacterial virulence. Overall, our study provides evidence that Pho is a global regulator of gene expression in C. rodentium and indicates the presence of at least two previously unrecognized virulence determinants of C. rodentium, namely, DegP and NleG8.

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“…Reddening inside and around the buccal cavity was often observed in infected specimens even in the absence of lesions. Both signs are typically associated with E. ictaluri infections in teleost fish [32], [33]. Control and infected specimens were euthanized by a lethal dose of MS-222 diluted in water.…”

Section: Methodsmentioning

confidence: 99%

Discovery of J Chain in African Lungfish (Protopterus dolloi, Sarcopterygii) Using High Throughput Transcriptome Sequencing: Implications in Mucosal Immunity

2013

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J chain is a small polypeptide responsible for immunoglobulin (Ig) polymerization and transport of Igs across mucosal surfaces in higher vertebrates. We identified a J chain in dipnoid fish, the African lungfish (Protopterus dolloi) by high throughput sequencing of the transcriptome. P. dolloi J chain is 161 aa long and contains six of the eight Cys residues present in mammalian J chain. Phylogenetic studies place the lungfish J chain closer to tetrapod J chain than to the coelacanth or nurse shark sequences. J chain expression occurs in all P. dolloi immune tissues examined and it increases in the gut and kidney in response to an experimental bacterial infection. Double fluorescent in-situ hybridization shows that 88.5% of IgM+ cells in the gut co-express J chain, a significantly higher percentage than in the pre-pyloric spleen. Importantly, J chain expression is not restricted to the B-cell compartment since gut epithelial cells also express J chain. These results improve our current view of J chain from a phylogenetic perspective.

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Mortality and pathology in brown bullheads Amieurus nebulosus associated with a spontaneous Edwardsiella ictaluri outbreak under tank culture conditions

Cited by 27 publications

References 20 publications

Mortality and pathology of hybrid catfish, Clarias macrocephalus (Günther) × Clarias gariepinus (Burchell), associated with Edwardsiella ictaluri infection in southern Thailand

Mortality and pathology of hybrid catfish, Clarias macrocephalus (Günther) × Clarias gariepinus (Burchell), associated with Edwardsiella ictaluri infection in southern Thailand

Genome-Wide Analysis of the Pho Regulon in a pstCA Mutant of Citrobacter rodentium

Discovery of J Chain in African Lungfish (Protopterus dolloi, Sarcopterygii) Using High Throughput Transcriptome Sequencing: Implications in Mucosal Immunity

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