title: Development of a novobiocin-resistant Edwardsiella ictaluri as a novel vaccine in channel catfish (Ictalurus punctatus).
abstract: The efficacy of a novel attenuated Edwardsiella ictaluri vaccine (B-50348) was determined in channel catfish (Ictalurus punctatus) by bath immersion and intraperitoneal (IP) injection. The vaccine was developed from a virulent strain of E. ictaluri (AL93-58) through selection for novobiocin resistance. When channel catfish (average weight 10 g) were IP injected with 4.2 × 10⁶ colony-forming units (CFU) of the attenuated vaccine B-50348, no fish died. However, when the same age and size matched group of the catfish were IP injected with a lesser amount (2.4 × 10⁶ CFU/fish) of modified live RE-33 vaccine or the AL93-58 virulent strain (2.5 × 10⁶ CFU/fish) of E. ictaluri, 65% and 95% fish died, respectively. When channel catfish were challenged with AL93-58, relative percent survival values of vaccinated fish were all greater than 90% at 22, 32, and 63 days post B-50348 vaccination through intraperitoneal injection. By bath immersion, at 37 and 57 days post vaccination of B-50348, relative percent survival values were both 100% when fish were challenged by virulent E. ictaluri AL93-58. Our results suggest that B-50348 could be used as a novel safe and efficacious vaccine against ESC in channel catfish.
authors.affiliation: Aquatic Animal Health Research Unit, USDA-ARS, 990 Wire Road, Auburn, AL 36832, USA. Julia.Pridgeon@ars.usda.gov
authors.forename: Julia W
authors.initials: JW
authors.lastname: Pridgeon
authors.forename: Phillip H
authors.initials: PH
authors.lastname: Klesius
mesh_terms: D000818:Animals; D001428:Bacterial Vaccines / Q000276:immunology*; D024881:Drug Resistance, Bacterial; D020610:Edwardsiella ictaluri / Q000187:drug effects / Q000276:immunology / Q000472:pathogenicity; D004756:Enterobacteriaceae Infections / Q000276:immunology / Q000517:prevention & control; D004797:Enzyme-Linked Immunosorbent Assay; D005393:Fish Diseases / Q000276:immunology / Q000401:mortality / Q000517:prevention & control; D007059:Ictaluridae / Q000276:immunology*; D009675:Novobiocin / Q000494:pharmacology; D010957:Plasmids / Q000187:drug effects; D014613:Vaccines, Attenuated / Q000276:immunology
chemical_list: D001428:Bacterial Vaccines; D014613:Vaccines, Attenuated; D009675:Novobiocin