Protection of rabbits against experimental pasteurellosis by a streptomycin-dependent Pasteurella multocida serotype 3:A live mutant vaccine

Abstract

Pasteurella multocida (serotype 3:A) was isolated from a rabbit with clinical signs of suppurative rhinitis. This P. multocida strain was mutagenized wih Nmethyl-N'-nitro-N-nitrosoguanidine to obtain a genetically stable streptomycindependent mutant, from which a live vaccine was prepared. Pasteurella-free rabbits were inoculated intranasally three times at weekly intervals and challenged intranasally with a virulent serotype 3:A rabbit P. multocida isolate 2 weeks after the third vaccination. The rabbits were killed 2 to 3 weeks later. The vaccine did not cause clinical disease, death, or gross or microscopic lesions. Furthermore, the vaccine protected the challenge rabbits from developing clinical disease, death, and gross lesions. However, mild focal lung lesions were noted in several of the vaccinated-challenged animals. In contrast, nonvaccinated-challenged rabbits developed pyrexia and anorexia. Furthermore, three of four of these rabbits died with severe gross lesions including pyothorax, suppurative pericarditis, and fibrinopurulent pneumonia. Microscopically, the four nonvaccinated rabbits had moderate to severe suppurative pneumonia and mild to moderate suppurative rhinitis, and two had mild tympanitis. The mutant vaccine did not appear to colonize the nasal cavities. The vaccine prevented the colonization of the virulent challenge organism in lungs, liver, spleen, genital tracts, and blood, but not the nasal cavities.

Identification of immunogenic outer membrane proteins of Pasteurella multocida 3:A in rabbits

“…Pasteurella multocida is an important pathogen in rabbits that causes suppurative rhinitis, otitis media, pneumonia, conjunctivitis, pyometra, subcutaneous abscesses, and septicemia (3,13). The disease is often latent; however, under various conditions of stress, severe clinical expressions of disease may occur.…”

Naturally occurring pasteurellosis in laboratory rabbits: chemical and serological studies of whole cells and lipopolysaccharides of Pasteurella multocida

“…Although additional studies will be required to determine the reason(s) for these observations, we suspect that antigenic determinants on the LPS may be altered by the method of extraction, ionic strength of the solution (8.5% NaCl solution versus distilled water), the presence of non-LPS in the extract, and the degree of aggregation of constituents of the extracts. Other surveys of somatic antigens from rabbit isolates of P. multocida consistently reveal that type 12 is the most prevalent serotype (4,13,22). That rabbits harbor unique serotypes of P. multocida is suggested by the studies demonstrating that several isolates of P. multocida are not typable with the 16 reference sera used in the GDPT (4,13,26).…”

“…Treatment of pasteurellosis with antibiotics, usually penicillin, may temporarily retard progress of the disease but is not curative. Recent studies on the pathogenesis of rabbit pasteurellosis have emphasized the morphological changes in infected tissues (15), granulocyte function (18), and in vivo colonization by mutant strains (12,22). Although a few studies have addressed the serological features of rabbit isolates of P. multocida (4,13,23,24), most investigations of the serology of P. multocida have involved the study of isolates from cattle and fowl in which the organism causes hemorrhagic septicemia and fowl cholera, respectively.…”

Development of Gamma Irradiation Vaccine against Mannheimia haemolytica: A Preliminary Study

“…The cells were harvested in 0.01 M phosphate-buffered saline, centrifuged, washed twice with phosphate-buffered saline and diluted to 3.6×10 10 cells/mLG 1 . All groups were inoculated subcutaneously with the challenge organisms at dose 0.5 mL per rabbit, the challenge dose was according to Lu and Pakes (1981).…”