Molecular Typing of Pasteurella multocida strains recently isolated from Poultry flocks

Pasteurella multocida (P. multocida) is a wide-range pathogen that infects poultry and animals. The objective of this study is to use molecular biology techniques to develop a fast characterization and genotyping strategy for P. multocida. Sixty bacterial isolates were isolated from suspected Pasteurella outbreaks in two chicken farms in El-Sharkia Governorate, Egypt, during April 2025. These 60 strains were subjected to chemical and bacteriological identification using traditional methods for both tests. Afterwards, the positive isolates were utilized in molecular identification of capsular typing using PCR targeting the universal primer (KMT1 gene) and multiplexing PCR using primers targeting the different serogroups (A, B, D, E, and F). Out of 60 samples, only 45 isolates tested positive for Pasteurella both morphologically and biochemically. All isolates exhibited different levels of sensitivity to the tested antibiotics. The molecular identification showed that only 40 isolates showed the expected 460 bp targeting the (KMT1 gene). Molecular capsular typing of positive PCR strains showed 1044 bp belonging to type A (22 strains), and 3 strains showed 760 bp corresponding to the B type (uncommon). Those 25 isolates were molecularly negative for the D, E, and F capsular antigens. Meanwhile, 15 PCR-positive isolates were untypable. In conclusion, the majority of the isolated Pasteurella strains were phenotypically and genotypically confirmed to be P. multocida type A from a local Egyptian poultry farm. Compared to biochemical analysis and traditional serotyping, which can take a lengthy period, PCR typing could allow for the quick and accurate characterization of P. multocida and confirm its identity. Since reference antisera are not accessible, it can shorten the time required to produce polyvalent vaccines. Moreover, the continuous identification of field strains of Pasteurella may provide better data to control Pasteurellosis in Egypt