Abstract
Three hundred fifty-six animal isolates of indole-positive urease-negative cultures of Pasteurella, which would formerly have been classified as P. multocida, were examined with respect to their relationship to the recently described P. multocida subspecies (ssp.) multocida, septica, and gallicida and P. canis, P. stomatisl Taxon 16, and Pasteurella sp. B. Two hundred sixty-three (73.9%) of the cultures could be identified with one of these taxa, and 93 isolates (26.1%), representing 17 different biotypes, were unassignable. Pasteurella multocida ssp. multocida was the predominant taxon throughout and in most of the 25 animal species from which isolations were made. In dogs, P. canis was the most frequent. Different degrees of host predilection were observed also in P. multocida ssp. septica for cats, P. canis for sheep, and 2 of the unassignable biotypes for cattle and dogs, respectively. Overall, the respiratory tract was the most frequent source of isolates, but a propensity of P. multocida ssp. septica for localization in the central nervous system of cats was noted.