Detection of Methicillin-Resistance Gene in Staphylococcus aureus Isolated from Traditional White Cheese in Iran

Methicillin-resistant staphylococcus aureus (MRSA) is considered as a major pathogen in public health concern. The objectives of this study were to firstly determine antibiotic sensitivity among Staphylococcus aureus isolated from traditional Iranian white cheese during 2015 from Hamedan province of Iran; and secondly to estimate the presence of methicillin-resistant S. aureus. This cross-sectional study was done by collecting 120 Iranian white cheeses (traditional and industrial) which were available in different markets; and tested for the presence of S. aureus by culture methods. The obtained isolates were subjected to disc diffusion antimicrobial susceptibility tests followed by PCR detection of the mecA gene. Out of 120 examined cheese samples, 19 samples (31.67%) were contaminated with S. aureus. The highest rate of antibiotic resistance was observed for penicillin, as all of the 19 isolates (100%) were found to be resistant to this antibiotic using disk diffusion method. Three out of 19 S. aureus isolates (15.7%) were phenotypically resistant to methicillin (disk diffusion), while 4 (21.05%) of them were genotypically confirmed as MRSA strains. Furthermore, none of the isolates were found resistant to vancomycin. The results of the study confirm the presence of methicillin resistant strains of S. aureus in Iranian white cheese. It should be considered to constitute a potential health risk for consumers, suggesting usage of more stringent hygiene measures.