Vol. 9, Special Issue 12, Part C (2025)

The present study was conducted to determine the sequence diversities between capsular serotypes A and D of P. multocida isolates of porcine origin with respect to the toxin gene region. Cloning and sequencing of the toxA gene of P. multocida type A and D isolates from pigs in North Eastern India was carried out using the pGEM-T^® Easy vector. Partial toxA gene sequences from 5 isolates of P. multocida were compared with the sequences of P. multocida available in the GeneBank database. Phylogenetic analysis revealed that the isolates shared 96-100% nucleotide (nt) and 97.5-100% amino acid (aa) sequence identity among themselves. The phylogenetic analysis also showed that the toxA genes Assam isolates of P. multocida (both type A and D) clustered separately from other global isolates, while maintaining a close phylogenetic relationship between the two local types. These findings indicate possible genetic variation in the toxA gene of local P. multocida isolates, which may have implications for diagnostics and vaccine development.