Phenotypic characterisation of Pasteurella multocida isolates from Australian poultry

Area of Science:

• Veterinary microbiology
• Bacteriology
• Poultry disease research

Background:

• Pasteurella multocida is a significant bacterial pathogen in poultry.
• Accurate identification and subtyping of P. multocida are crucial for disease control.
• Phenotypic characterization aids in understanding bacterial diversity and pathogenicity.

Purpose of the Study:

• To perform a detailed phenotypic characterization of 110 Pasteurella multocida isolates from Australian poultry.
• To compare these isolates against reference strains of recognized Pasteurella species.
• To identify and classify the isolates into distinct biochemical biovars and subspecies.

Main Methods:

• Phenotypic characterization of 110 bacterial isolates previously identified as Pasteurella multocida.
• Inclusion of reference strains from recognized Pasteurella species for comparative analysis.
• Biochemical testing to delineate ten distinct biovars among the isolates.

Main Results:

• 91 isolates were identified as Pasteurella multocida subspecies multocida across four biovars.
• One isolate was identified as P. multocida subspecies septica, and five as P. multocida subspecies gallicida.
• Two biovars (seven isolates total) could not be assigned to currently recognized subspecies, indicating potential novel diversity.

Conclusions:

• The study identified significant phenotypic diversity within Australian poultry P. multocida isolates.
• A substantial proportion of isolates confirmed to P. multocida subspecies multocida, P. multocida subspecies septica, and P. multocida subspecies gallicida.
• The presence of unclassified biovars highlights the need for further taxonomic investigation within the Pasteurella genus.