Fig. 2

Phylogenetic trees of partial ompA genes and proteins. Molecular evolutionary history of partial ompA genes (a) and proteins (b) obtained from 186 P. multocida isolates associated with diseased cattle, water buffaloes, and pigs in Thailand in comparison with 41 available ompA genes and proteins from the NCBI database. The phylogenetic relationships were inferred using the neighbour-joining method. Evolutionary analyses were conducted in MEGA 6. The bovine clusters (C1 and C2) are labelled in the dark blue bars, and the porcine clusters (P1, P2, P3, and P4) are labelled in the green bars. The P4 subcluster consists of the P4I and P4II groups. Details regarding each cluster are presented in Additional file 2: Table S2