University of Tehran Iranian Journal of Veterinary Medicine 2251-8894 10 2 2016 04 01 Frequency of selected virulence-associated genes in intestinal and extra-intestinal Escherichia coli isolates from chicken فراوانی برخی از ژن های مرتبط با حدت در جدایه های روده ای و خارج روده ای اشرشیا کلی با منشاء ماکیان 91 96 57894 10.22059/ijvm.2016.57894 EN Sara Eftekharian DVSc (Microbiology) Student, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran Masood Ghorbanpoor Department of Pathobiology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran Masoud Reza Seyfi Abad Shapouri Department of Pathobiology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran Reza Ghanbarpour Molecular Microbiology Research Group, Faculty of Veterinary Medicine, Shahid Bahonar University, Kerman, Iran Ramazanali Jafari Jafari Department of Clinical Science, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran Amir Amani DVSc (Poultry Diseases) Graduate, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran Journal Article 2016 01 26 <strong>Background:</strong> Although <em>Escherichia coli</em> (<em>E. coli</em>)<br />is a part of intestinal normal microflora of warm-blooded animals, including<br />poultry, outbreaks occur in poultry raised below standard sanitation and during<br />the course of respiratory or immunosuppressive diseases. Avian pathogenic <em>E.<br />coli</em> (APEC) harbors several genes associated with virulence and<br />pathogenicity. APEC strains are responsible for some diseases in poultry<br />including colibacillosis, swollen head syndrome, yolk sac infection, omphalitis<br />and coli granuloma. <strong>OBJECTIVES:  </strong>The<br />aim of this study was examination of the presence and frequency of three<br />important virulence genes in intestinal and extra-intestinal (liver) <em>E. coli</em><br />isolates from chicken of Khuzestan province in the southwest of Iran. <strong>METHODS:</strong><br />Totally 120 (60 intestinal and 60 liver) <em>E. coli</em> isolates were examined<br />by polymerase chain reaction (PCR) for the presence of aerobactin (iutA),<br />temperature sensitive hemagglutinin (tsh) and fimbriae type 1 (fimH )<br />genes.  <strong>RESULTS:</strong> The results showed<br />that tsh, iutA and fimH are respectively present in 78.3%, 70% and 61.7% of<br />liver isolates while in intestinal ones the frequency of these genes was 21.7%,<br />41.7% and 41.7% respectively. The most prevalent genotypes in extra intestinal<br />and intestinal isolates were tsh+fimH+iutA+ and tsh-fimH-iutA-respectively. <strong>CONCLUSIONS:</strong> It seems that these sets of virulence genes are significantly more<br />prevalent (P<0.05) in extra intestinal isolates and probably these genes<br />play an important role in the pathogenesis of APEC isolates in the southwest of<br />Iran. Although these virulence genes were not present in all APEC isolates  their frequencies were high and using the<br />products of these genes in vaccines may be effective in protecting against<br />infections caused by this bacterium https://ijvm.ut.ac.ir/article_57894_cd79717316eb5403bf031a8bd0e09455.pdf