title: Characterization of attenuated Renibacterium salmoninarum strains and their use as live vaccines.
abstract: Two nutritionally mutant strains of Renibacterium salmoninarum (Rs) were isolated that grew on tryticase soy agar (Rs TSA1) or brain heart infusion agar (Rs BHI1). These 2 strains could be continuously cultured on these media, whereas typical R. salmoninarum would only grow on KDM-2 agar. We determined no other phenotypic difference that could be used to distinguish them from wild-type R. salmoninarum. Both strains were found to be avirulent when 5 x 10(6) bacteria were intraperitoneally (i.p.) injected into Atlantic salmon. Rs TSA1, Rs BHI1, and Rs MT-239 (a R. salmoninarum strain previously shown to be attenuated) were tested as live vaccines in 2 separate trials. The best protection was seen with Rs TSA1. Vaccinated Atlantic salmon had relative percent survival (RPS) of 50 at 74 d post-challenge in Trial 1 and 76 at 60 d post-challenge in Trial 2. In both trials, 100% of the control salmon died from bacterial kidney disease (BKD) (within 40 d for Trial 1 and 50 d for Trial 2) after i.p. challenge with 5 x 10(6) live cells of the virulent isolate Rs Margaree.
authors.affiliation: Division of Natural Sciences, Purchase College, State University of New York, 10577, USA. jdaly@purchase.edu
authors.forename: J G
authors.initials: JG
authors.lastname: Daly
authors.forename: S G
authors.initials: SG
authors.lastname: Griffiths
authors.forename: A K
authors.initials: AK
authors.lastname: Kew
authors.forename: A R
authors.initials: AR
authors.lastname: Moore
authors.forename: G
authors.initials: G
authors.lastname: Olivier
mesh_terms: D000818:Animals; D001428:Bacterial Vaccines; D005393:Fish Diseases / Q000517:prevention & control*; D016908:Gram-Positive Bacterial Infections / Q000517:prevention & control / Q000662:veterinary*; D008835:Micrococcaceae / Q000276:immunology*; D020317:Salmo salar; D014611:Vaccination / Q000662:veterinary; D014613:Vaccines, Attenuated
chemical_list: D001428:Bacterial Vaccines; D014613:Vaccines, Attenuated