Abstract: In order to understand the variation of outer membrane protein H (ompH) gene and the correlation with capsular type, the capsular typing and ompH gene of 44 strains of P.multocida were examined and anlalyzed by PCR method.The results showed that 22 strains were capsular type A, 17 strains were capsular type B, 5 strains were identified as capsular type D.The open reading frames of ompH gene were from 1 002 to 1 056 bp.The predicted maturation proteins were composed of 313 to 331 amino acids except the signal peptide including 20 amino acid residues in N terminal.The molecular weight of maturation proteins were from 33.83 to 36.46 ku.The alignment data indicated that the nucleotide sequence homologies were from 86.2% to 100.0%, and the homology of amino acid were from 86.0% to 100.0%.The phylogenetic tree constructed by the ompH gene showed that capsular type A, B and D strains were in different branches.The sequence analysis results showed the ompH gene of P.multocida isolated from swine had high homology among different serotypes.At the same time, there was a correlation between capsular type and the ompH gene.

Key words: Pasteurella multocida; capsular type; ompH gene; sequence analysis