Distribution of virulence adhesin associated genes and antimicrobial susceptibility in Pasteurella multocida from ovine pasteurellosis in Iran

Pasteurella multocida is an opportunistic pathogen responsible for pneumonia of lambs and goats, respiratory atrophic rhinitis of swine. Although the molecular basis of the pathogenicity and host specificity of P. multocida is not well understood, several studies have reported that a number of proteins are correlated with the pathogenic mechanisms. Adhesins have a crucial role in mediating colonization and invasion of the host. Thus, their presence on the bacterial surfaces is usually correlated with virulence. The aim of this study was identify the adhesion associate genes and antimicrobial suscaptability among ovine P. multocida isolates from Iran. Of the thirty tested strains, 3.4% (1/30) were susceptible to all (12 antibiotics) tested drugs, and 83.4% (25/30) were resistant to at least one drug tested. The resistance was more frequent to streptomycin (83.3%), followed by tylosin and penicillin (46.6%). The results of PCR analysis for the frequency of virulence-associated genes indicted that the genes encoding adhesins (ptfA, fimA, hsf-1 and ompH), were each found in more than 93.0% of the isolates. In contrast, the frequency of 2 genes (pfhA and tadD) were 36%. All the tested isolates were positive for fimA and ompH (100%). Five different virulence profiles (P1 - P5) were obtained among the 30 isolates of ovine origin, and profile P2, harboring all adhesion genes except pfhA and ptfA, had the highest frequency. The results of this investigation provide useful information for understanding the antimicrobial resistance patterns, capsular types and adhesin genes prevalence of P.multocida isolate from sheep in Iran.