The immunogenicity and pathogenicity of Pasteurella multocida isolated from poultry in Indonesia

Of 13 field isolates of Pasteurella from chickens and ducks in Indonesia, 10 were confirmed as P. multocida subspecies multocida, one as P. multocida subspecies gallicida and one as P. multocida subspecies septica. Nine were capsular Type A four were Serotype 1, one was Serotype 4, one was Serotype 11, one was Serotypes 4,12, and the remaining six were untypable. Five isolates were pathogenic for mice and two were pathogenic for chickens. Both a trivalent vaccine which included local field isolates and an imported commercial vaccine, were efficacious in layer chickens against challenge with virulent reference and local field strains. Though not statistically significant, the protection provided by the trivalent vaccine against virulent field isolate challenge was slightly better and could provide an improvement over the currently used imported vaccine although further field trials are required. A bacterin vaccine produced from a Serotype 1 field isolate grown in the allantoic sac of embryonated chicken eggs provided chickens with good cross protection against heterologous serotype challenge.