Development of a PCR test based on a gene region associated with the pathogenicity of Pasteurella multocida serotype B:2, the causal agent of haemorrhagic septicaemia in Asia.

We have developed a PCR assay to detect Pasteurella multocida serotype B:2, the causal agent of Haemorrhagic Septicaemia (HS) in Asia. Nucleotide sequence determination of a 16S rRNA-23S rRNA PCR product unique to B:2 strains was shown to share amino acid sequence homology with a bacteriophage Mu protein. Primers designed from this sequence when tested against a panel of isolates recovered from a wide geographical area and representing a large range of bacterial genera and species, were found to specifically amplify DNA from P. multocida, serotype B:2. Southern hybridisation confirmed the presence of this sequence in only the B:2 serotype of P. multocida, suggesting an association between bacterial virulence and the presence of bacteriophage genes in the bacterial genome. The results of this study demonstrate the potential application of PCR to the diagnosis of HS in cattle and buffalo in Asia. Application of PCR to support diagnosis of HS will greatly improve accuracy, laboratory response time, and will facilitate rational deployment of resources for controlling this disease.