Isolation and genetic characterization of Vancomycin-Resistant and mecC+ Methicillin-Resistant Staphylococcus aureus strains in clinical samples of Bojnurd, Northeastern Iran

: Background. The emergence of antibiotic-resistant Staphylococcus aureus strains is one of the major concerns about the various Staphylococcal infections. Vancomycin is one the most important effective antibiotics on Staphylococcal lethal infections. To date, Vancomycin-Resistant strains are increasingly isolated in different parts of the world and go to the alerting condition in antibiotic usage strategies. Methods. Staphylococcus aureus isolates were collected from different clinical samples in Imam Reza Hospital, Bojnurd. After identification using conventional methods were then evaluated with agar screening, disk diffusion, and MIC methods to determine resistance to vancomycin and methicillin. We also performed PCR for the detection of mecA, mecC, vanA, and vanB genes. After confirmation of vancomycin resistance, genetic analysis was performed using SCCmec, agr, and spa typing, and MLST methods on Vancomycin Resistant Staphylococcus aureus (VRSA) isolates. Results. We found four vancomycin-resistant isolates (1.29%). Also, 75% of isolates were resistant to cefoxitin. Using the PCR method, we found mecA in 73%, mecC (0.64%), and vanA in 1.29%. Interestingly we found two mecC positive isolates in Methicillin Resistant Staphylococcus aureus (MRSA) isolates. The alpha-hemolysin (81.81%) and enterotoxin C (27%) had the highest and lowest toxins percentage, respectively. In mecA positive isolates, SCCmec IV (37%), SCCmec III (31.27%), SCCmec I (14%), SCCmec II (11%), and SCCmec V (5.7%) were the most prevalent SCCmec types, respectively. It should be noted that the two mecC positive isolates belonged to SCCmec XI. Agr I (76.29%) was the highest agr type. We recognized t037as dominant spa type and ST239, ST6, ST97, and ST8 were found in VRSA isolates. Conclusion. The frequency of mecA genes in methicillin resistance of S. aureus is very high. It seems that the resistant isolates belonged to endemic clones of Iran.