Introduction: Staphylococcus aureus has long been recognized as a pathogen of worldwide clinical significance. Over the last two decades, methicillin resistant S. aureus (MRSA) strains have become endemic in hospitals worldwide. Protein A is an antiphagocytic protein encoded by spa gene. spa types can be determined via amplification and sequencing of the X region of the spa gene, which contains polymorphic direct repeats. Diversity of X region causes variation in different protein A Staphylococcus aureus. Strain typing of S. aureus is a good tool for epidemiological studies. In this research, the diversity of spa types of all the MRSA isolates and one isolate of the representative MSSA from apparently healthy broiler in Ilam in southwest of Iran was established. Methods: In this study, 200 bacterial strains were isolated from broilers in Ilam, of which 107 (53.51%) identified to the species level by standard methods such as Gram staining, blood and mannitol salt agars, catalase and oxidase testing. Isolates were confirmed as MRSA by oxacillin and cefoxitin susceptibility testing according to the CLSI guidelines. All isolates were also evaluated for the presence of the femA and mecA genes by PCR. All nine strains of confirmed MRSA as well as one isolate of MSSA were then subjected to spa typing using the primers Spa-1113f (AGACGATCCTTCGGTGA) and Spa-1514r (CAGCAGTAGTGCCGTTTG) in the standard protocol. The amplified spa gene fragments were purified and sequenced. Spa types were assigned by using Ridom SpaServer. Results: All MRSA isolates contained a mecA gene, confirming phenotypic characterization results. The percentages of colonization by MSSA and MRSA were (91.59%, n=98) and (8.41%, n=9), respectively. spa typing of the 10 isolates revealed five different spa types. Repeats among the spa types varied from 5 (t567) to 10 (t002). Of 9 MRSA, four isolates belonged to t011 (44.44%); the next majority with two isolates each was belonged to t002 and t567 (22.22%). Spa type t1184 represented for the last MRSA isolate in the study and spa type for MSSA isolate was come out as t304. Discussion & Conclusion: The predominant spa type t011 in this research, has been reported as the most common type among livestock- associated MRSA, mainly isolated from pork meat and cow and to lesser extend from poultry meat. Thus, our finding would add value to the previous reports. To the best of our knowledge, three spa types including t304, t567 and t1184, that previously not reported from Iran, were identified in this research. Further study of S. aureus isolates from broiler and other types of poultry should be conducted to elucidate the current status of S. aureus.
