Antibiotic Susceptibility of Ornithobacterium rhinotracheale (ORT) Isolated in broiler chickens of Arak, Markazi province 2017

Introduction and Objectives: Respiratory diseases cause considerable damage to the poultry industry in worldwide and various bacterial and viral agents involved in its creation. In recent years, Ornithobacterium rhinotracheale (ORT) bacterial disease has been reported from different parts of the world frequently including of Iran as poultry respiratory infections. Materials and Methods: In this study, 231 samples from each bird with respiratory signs were collected by taking of lungs, trachea, ocular sinus swaps and corps from Arak poultry farms during August 2011 to March 2013. The samples were cultured on blood agar medium with 5% sheep blood containing Gentamicin and Polymyxin B and then incubated with 7.5% CO2 at 37 °C for 48 to 72 hours. The bacteria identification was carried out using biochemical tests.Results: The antimicrobial susceptibility of the bacteria to 17 common antibiotics which used in poultry farms was determined by Kirby & Bauer method as well. In this study, the ORT bacteria were isolated from the 15 out of 231 (6.5%) samples that means 20% of Arak poultry farms are infected by ORT .All of the isolates were resistant to Gentamicin, Enrofloxacin, Erythromycin, Penicillin, Amoxicillin, Colistin, Lincomycin and Polymyxin B completely. These isolates also were mostly sensitive to Nitrofurantoin.Conclusion: The results of this study indicate that 20% of the examined poultry farms of Arak city are infected with the Ornithobacterium rhinotracheale (ORT) and have highly resistant to current antibiotics.

Keywords:

Ornithobacterium rhinotracheale , poultry , respiratory infections , Kirby & Bauer.