Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 11 3 2019 07 25 191 197 EN Motahare Feizabadi Farahani Department of Central Laboratory, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization, Tehran, Iran Majid Esmaelizad Department of Central Laboratory, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization, Tehran, Iran Ahmad Reza Jabbari Department of Pasteurella National Research Laboratory, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization, Tehran, Iran 2018 07 29 2019 02 21 Background and Objectives: Iron is an essential compound in metabolic pathway of wide range of organisms. Because of limited free iron supply in mammalian and avian hosts, bacteria have applied various ways to acquire iron. Materials and Methods: In this study, the frequency of 8 iron acquisition factors was examined among 63 avian and ovine Pasteurella multocida field isolates and their vaccine strains using PCR method. Results: Five candidate genes (fur, tonB, exbD, exbB and hgbA) were identified among all isolates. For the first time, 2 loci (hgbB1 and hgbB2) of the hgbB gene were identified, which were previously reported as 1 gene. Also, it was found that 5 ovine and 1 avian isolates possessed all the virulence factors, which could also be considered for evaluating the frequency of other virulence factors. Conclusion: More studies need to be conducted on the frequency of all other virulence factors among these isolates, which can provide basic information for improvement or substitution of current vaccinal strains. Overall, as the new designed sets of primers showed more potential in detecting the corresponded genes, researchers can consider them in further studies. https://ijm.tums.ac.ir/index.php/ijm/article/view/1841 https://ijm.tums.ac.ir/index.php/ijm/article/download/1841/1172