Phylogenetic Analysis Based on OmpA Protein Sequences of Diverse Pasteurella multocida Strains Originated from Different Animal Host Species

Pasteurella multocida causes endemic diseases of economic importance in livestock. A number of capsular serotypes of P. multocida bacteria are associated with different clinical diseases in the host species. Outer membrane proteins (OMPs) are at the interface of bacterium and host which are likely to play an important roles in host specificity and disease. The prime objective of the present study was to comparatively analyze seven P. multocida strains obtained from sheep, buffaloes, rabbit and pigs succumbed to different clinical conditions by ompA gene sequence analysis in conjunction with the capsular type. The ompA genes of various capsular serotypes from host species origins were amplified and sequenced. Further, sequence, phylogenetic and structural analyses were carried out. Analysis revealed that length of CDs region in different serogroups of P. multocida varied from ~ 1050 to 1077 bp, being highest in serogroups B (1077 bp) and lowest in serogroups A of rabbit strain (1050 bp). Nucleotide length was same in all sheep serogroup A strains (1059 bp). Protein domain analysis of OmpA showed signal peptide, N-terminal ompA domain and C-terminal ligand binding domain. The phylogenetic analysis showed two major clusters of the bovine and porcine/ sheep/rabbit/human strains, which was further divided in to different sub clusters such as subcluster I = NIVEDIPm sheep strains serogroup A, subcluster II = NIVEDIPm rabbit strains serogroup A, subcluster III = NIVEDIPm pig strains serogroup A, subcluster IV = NIVEDIPm pig strains serogroup D, subcluster V = NIVEDIPm bovine strains serogroup B. This study concluded that the clustering of P. multocida based on ompA proteins was associated with capsular serogroup and host species.