title: Edwardsiellosis caused by Edwardsiella ictaluri in laboratory populations of Zebrafish Danio rerio.
abstract: We report the first cases of Edwardsiella ictaluri causing epizootics in laboratory populations of Zebrafish Danio rerio. Edwardsiella ictaluri is primarily recognized as a disease of catfish species and is known to cause an economically important bacterial disease of farm-raised catfish in the USA and abroad; however, it has been isolated on occasion from 10 other genera of nonictalurid fishes. We isolated E. ictaluri from moribund Zebrafish held in quarantine at two different universities in two states and from a research facility in a third state between February 23 and December 6, 2011. Edwardsiellosis in Zebrafish can be described as a severe systemic disease characterized by tissue necrosis and the presence of large numbers of extracellular and intracellular bacteria, often within macrophages. The kidneys (pronephros and mesonephros), spleen, nares, and forebrain were the most commonly and severely affected tissues. In outbreaks, mortality was acute and numerous fish died over a 1-2 week period. Mortality continued until the majority of the population was lost, at which time the remaining fish were euthanized. In addition to these cases, four cultures of bacteria isolated from Zebrafish by another diagnostic laboratory were submitted to the Louisiana Aquatic Diagnostic Laboratory for identification and were confirmed as E. ictaluri. In total, eight cultures of E. ictaluri from Zebrafish from Louisiana, Massachusetts, Pennsylvania, and Florida were identified. The isolates were confirmed as E. ictaluri by biochemical phenotype, API 20E (bioMérieux), and amplification and sequencing of a portion of the 16S rRNA gene. Edwardsiella ictaluri isolates from Zebrafish are believed to comprise a unique group and were differentiated from catfish isolates by exhibiting weaker motility, autoaggregation in broth, a different plasmid profile (two plasmids of 4.0 and 3.5 kb), a different API 20E code (4204000), and lack of lipopolysaccharide recognition with Mab Ed9.
authors.affiliation: a Department of Pathobiological Sciences, School of Veterinary Medicine , Louisiana State University , 1909 Skip Bertman Drive , Baton Rouge , Louisiana , 70803 , USA.
authors.forename: John P
authors.initials: JP
authors.lastname: Hawke
authors.forename: Michael
authors.initials: M
authors.lastname: Kent
authors.forename: Matt
authors.initials: M
authors.lastname: Rogge
authors.forename: Wes
authors.initials: W
authors.lastname: Baumgartner
authors.forename: Judy
authors.initials: J
authors.lastname: Wiles
authors.forename: Johnny
authors.initials: J
authors.lastname: Shelley
authors.forename: L Christine
authors.initials: LC
authors.lastname: Savolainen
authors.forename: Robert
authors.initials: R
authors.lastname: Wagner
authors.forename: Katy
authors.initials: K
authors.lastname: Murray
authors.forename: Tracy S
authors.initials: TS
authors.lastname: Peterson
mesh_terms: D000818:Animals; D000830:Animals, Laboratory; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000911:Antibodies, Monoclonal; D004196:Disease Outbreaks / Q000662:veterinary; D024881:Drug Resistance, Bacterial; D020610:Edwardsiella ictaluri / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D004756:Enterobacteriaceae Infections / Q000382:microbiology / Q000662:veterinary*; D005393:Fish Diseases / Q000382:microbiology* / Q000473:pathology; D010957:Plasmids / Q000235:genetics; D015027:Zebrafish
chemical_list: D000900:Anti-Bacterial Agents; D000911:Antibodies, Monoclonal