Bacteriological variation among Bordetella bronchiseptica isolates from dogs and other species.

Bacteriological properties of 50 isolates of Bordetella bronchiseptica were compared. Phase variation, which involved colonial morphology and its associated characters of hemagglutination, hemolysis, acriflavine agglutination; crystal violet staining, flagellation, and fimbriation, occurred among these isolates. Organisms representing the three observed morphotypes did not have different growth rates, nor were any differences in their bacteriological characteristics observed after repeated subculture on agar. There were also variations in antimicrobial drug susceptibility, especially to sulfonamide-trimethoprim, and in nitrate reduction. The relationships among these variable parameters were not apparent. None of the observed variations could be attributed to differences in the species of origin.