Phenotypic characterisation of Pasteurella multocida isolates from Australian poultry

A phenotypic characterisation of 110 isolates of bacteria previously identified as Pasteurella multocida was performed. Reference strains of many of the currently recognised species within the genus Pasteurella were included in the study. All the isolates had been obtained from Australian poultry - 67 from chickens, 42 from turkeys and one from a duck. Ten different biochemical biovars were recognised amongst the isolates. Four of these biovars, representing 91 isolates, were identified as P. multocida subsp. multocida. One biovar, consisting of one isolate, was identified as P. multocida subsp. septica and another biovar, consisting of five isolates, as P. multocida subsp. gallicida. Two further biovars were tentatively identified as ornithine decarboxylase negative P. multocida subsp. multocida (five isolates) and maltose positive P. multocida subsp. septica (one isolate). The final two biovars, consisting of five and two isolates each, could not be assigned to any of the currently recognised subspecies of P. multocida.