LAUSR

Pasteurella multocida possesses various virulence factors, including capsule, lipopolysaccharide, fimbriae, toxins, outer membrane proteins, and adhesions. Adhesins have a crucial role in mediating colonization and invasion of the host. The aim of the present study was to identify the prevalence of adhesion factor genes and resistance/sensitivity patterns among the avian P. multocida isolates from Iran. A total of 30 isolates of P. multocida were used for this study. All isolates were obtained from the poultry cases dead from fowl cholera in the northern parts of Iran. The results of the polymerase chain reaction analysis for the frequency of virulence-associated genes showed that the genes encoding adhesins (i.e., ptfA, fimA, hsf-1, pfhA, and ompH) were found in all (100%) of the isolates. However, the frequency of two genes including tadD and toxA were 50% and 70%, respectively. Thegenotyping patterns were classified into four groups according to the virulence factors in P. multocida isolates. Genotype pattern I, which included the isolates harbouring all of the examined virulence factor genes showed the highest frequency (43.3%). Pathogenicity test showed that all of the isolates classified as genotype I were pathogen or highly pathogen in the mice model. The sensitivity of the isolates to penicillin, ampicillin, lincospectin, florfenicol, tylosin, and tiamulin was 100%. However, the sensitivity rates to flumequin, enrofloxacine, and nalidixicacid were 96.6% and 80%, respectively. The findings of the current study will be helpful to elucidate the disease process and develop an efficient multivalent local vaccine.