Phenotypical and genotypical characteristics of paired isolates of Pasteurella multocida from the lungs and kidneys of slaughtered pigs.

Twenty-eight strains of Pasteurella multocida were isolated from 12 Danish and two Canadian abattoir pigs. Fourteen strains were isolated from pulmonary inflammatory lesions, and 14 strains were isolated from kidneys of the same animals. Phenotypical and genotypical characteristics of the strains were evaluated with a view to determine if P. multocida isolated from kidneys might have been disseminated from the lungs. All field strains were capsular type A. The biochemical reactivity in the API-20E and API-ZYM commercial test-kits was uniform with the exception of alpha-glucosidase activity which was present at low levels in only ten of the strains. One strain was markedly serum sensitive, six strains slightly sensitive and the remaining were serum resistant. The peptide patterns obtained by polyacrylamide gel electrophoresis of whole cell proteins of the strains were very uniform with the exception of differences in intensity of bands in the 38 and 34 kD regions. The pattern of oligonucleotides obtained after electrophoresis of total genomic DNA digested with BamHI showed that the paired isolates had identical patterns in eight of the 14 animals. It is therefore likely that isolates from kidney lesions represent blood borne dissemination from primary pulmonary lesions.