¹Dicle University, Faculty of Veterinary Medicine, Department of Microbiology, TR-21200 Diyarbakır - TÜRKİYE
²Republic of Turkey Ministry of Agriculture and Forestry Veterinary Control, Central Research Institute, Bacteriology Diagnostic Laboratory, TR-06020 Ankara - TÜRKİYE
³Ankara University, Faculty of Veterinary Medicine, Department of Microbiology, TR-06110 Ankara - TÜRKİYE DOI : 10.9775/kvfd.2022.28271 Avian pathogenic Escherichia coli (APEC) causes systemic or localized infections with different clinical courses such as septicemia, air sac disease, polyserositis and coligranuloma. Colibacillosis causes significant economic losses in the poultry industry due to the need for the control of the disease by causing carcass contamination, decreased feed conversion rate, mortality in poultry. In this study, 99 E. coli strains were isolated from different production units in the same integration. Antimicrobial susceptibility tests of all strains were performed and thirty strains with multidrug resistance (MDR) in the different production units were serotyped. The highest resistance was observed against oxytetracycline, erythromycin amoxicillin and doxycycline. Multidrug resistance was observed at a rate of 81.81% (81/99). Among the 30 strains that could be serotyped, O78 and O125 were determined as the most prevalent serogroups with 43.3% (13/30) and 16.6% (5/30) rates, respectively, while O1, O8, O18, O142, O143, O157, O158, O164 and O169 were found as rare serogroups. O78 was determined as a high antibiotic resistant strain in isolated E. coli strains and a dominant serotype in the selected strains and this study demonstrated that a correlation can be between breeders and their progeny. Keywords : Antibiotic resistance, Chicken, Escherichia coli, Serogroups