Vaccinal properties of Salmonella abortusovis mutants for streptomycin: screening with an ovine model.
Living attenuated vaccines may help control infection with Salmonella enterica subspecies enterica ser abortusovis in sheep without constraints incompatible with husbandry. Virulence and immunogenicity of 2 Abortusovis streptomycin-dependent strains and 3 reverse mutants were compared in sheep, the virulent parental strain Abortusovis 15/5 being used as reference. Reduction of virulence with conservation of some immunogenicity was demonstrated for the 5 mutant strains after intravenous or subcutaneous inoculation. A 5-day bacteriemia was detectable after intravenous inoculation with parental strain, whereas none was shown with mutant strains. Mutant reverse strains survived in loco-regional lymph nodes for at least 12 days. The dependent strain D5 and reverse strain Rv6 were selected for subcutaneous vaccination of 2 groups of 18 ewes 32 days before fecundation. Ten pregnant ewes per group and 10 unvaccinated ewes were randomly selected among pregnant animals and were challenged subcutaneously at mid-gestation. Both vaccines conferred protection, but Rv6 was more efficient than D5 and was chosen as the vaccinal strain.
Pardon
P
P
INRA, Station de pathologie de la reproduction, Unité de pathologie infectieuse ovine, Tours-Nouzilly, Nouzilly, France.
Marly
J
J
Lantier
F
F
Sanchis
R
R
D000818:Animals; D001428:Bacterial Vaccines; D005260:Female; D009154:Mutation; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000517:prevention & control / Q000662:veterinary*; D012475:Salmonella / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D012481:Salmonella Infections, Animal / Q000517:prevention & control*; D012756:Sheep; D012757:Sheep Diseases / Q000517:prevention & control*; D013307:Streptomycin / Q000378:metabolism; D014613:Vaccines, Attenuated; D014774:Virulence
D001428:Bacterial Vaccines; D014613:Vaccines, Attenuated; D013307:Streptomycin