Prevalence of Staphylococcus aureus resistant to methicillin in traditional cheese and cream: a study in city of Tabriz, Iran

In recent years isolation of antibiotic resistant Staphylococcus aureus, especially methicillin resistant Staphylococcus aureus in food and food-producing animals has become more frequent. The aim of this study was to determine the prevalence of MRSA in traditional white cheese and butter presented in Tabriz by culture and PCR techniques, as well as the determination of their antibiotical susceptibility. In the present study, 250 traditional white cheese and butter samples were collected from different producers across Tabriz. Evaluation for contamination by coagulase positive Staphylococcus aureus was done using the culturing method. The isolates were subjected to the PCR technique according to the Nuc gene in order to confirm Staphylococcus aureus and methicillin resistance to the gene (mecA) and the antibiotic resistance trend of the isolates were studied by the disc diffusion agar method. The culture of the samples indicated that 26 cheese and 24 butter samples were contaminated by coagulase positive Staphylococcus aureus. Nineteen cheese samples and 11 butter samples were confirmed to be Staphulococcus aureus based on PCR using the Nuc primer gene. From a total number of 30 isolates containing the Nuc gene, 11 had the resistant mec-A gene. In overall, from the evaluated samples 100% of the isolates demonstrated simultaneous resistance to more than 3 antibiotics. It can be stated that there was a considerable amount of Staphylococcus aureus which was resistant to a variety of antibiotics, most importantly methicillin resistant. Staphylococcus aureus in the evaluated samples.