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چکیده
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Introduction: The extensive use of antimicrobial agents in animal husbandry contributes to the selection of drug-resistant strains. The aim of this study was to determine antibiotic resistance pattern and investigate some prophage types, SGFa, SGFb and SGB in the methicillin-resistant Staphylococcus aureus (S. aureus) isolates from traditional dairy specimens in Ilam. Methods: One hundred and sixteen isolates were recovered from dairy products from 39 traditional dairy stores in Ilam, in the southwest of Iran. All the isolates were analyzed by using microscopic examination and standard biochemical tests to identify S. aureus to the species level. Multiplex PCR for the femA and mecA genes was performed to confirm the identification and methicillin-resistant S. aureus (MRSA). For prophage typing all S. aureus isolates were screened for SGFa, SGFb and SGB genes by PCR. Susceptibility to ten antibiotics was also determined according to CLSI guidelines, using disk diffusion test. Results: Thirty isolates were identified as S. aureus based on the results of phenotypic and molecular characterization of femA gene. Two isolates (~ 7%) harbored mecA gene and recognized as MRSA. The highest resistance to antibiotic were observed for doxycycline (~87%). For other antibiotics including tetracycline, cefexime, cefotaxime, penicillin G, vancomycin, amoxicillin and cefazolin, the resistance rates were recorded as ca. 67%, 57%, 43%, 16%, 13%, 10% and 6.5%, respectively. The least resistance were seen to imipenem antibiotics (3%). SGFa and SGFb prophages was positive for one isolate each (~3.5%) and two isolates (~ 7%) were positive for SGB prophage type. Discussion & Conclusion: Generally, all isolates were resistant to at least for 3 antibiotics. According to the number of the MRSA isolates and the presence of the prophage genes, one can conclude that the traditional dairy product could be raised as a resource of the S. aureus that carry these genes. Thus, this may pose a public health hazard, since it has been shown that S. aureus strains that carrying prophage genes and MRSA clone have the zoonotic potential and can act as livestock-associated-MRSA.
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