Antibiotic resistance patterns of Methicillin and Vancomycin -resistant Staphylococcus aureus isolated from Tehran hospitals' clinical samples

Today spreading of MRSA and VRSA became one of the most important treatment challenges. Antibiotic resistance development and Staphylococci pathogenicity patterns variations are considered as the significant virulence factors. The purpose of this study is to detect the antibiotic resistance patterns of clinical isolates in Tehran’s hospitals.

This study provides 502 clinical isolates from Tehran’s Hospitals. Detecting and confirming Staphylococcus aureus isolates have been done through biochemical identification and 16s rRNA replication via PCR method. All isolates have been studied with disk diffusion method in terms of Methicillin resistance as well as MIC method in terms of Vancomycin resistance. Finally, both groups have been studied with molecular methods.

After studying 502 S. aureus isolates, 168 MRSA, 6 VRSA, and 2 VISA isolates have been detected. Abundance of mecA in MRSA isolates was 99.4%. In VRSA however, the gene abundance was found to be 37.5 % for vanB, 37.5 % for vanC1, and 12.5 % for vanC3. The most resistant MRSA isolates have been sampled from catheters as well as elders. The most resistant VRSA and VISA isolates have also been detected in discharge and the isolates from elders.

VRSA and MRSA are considered as a serious threat for human health. Correct detection of the infection resistance patterns and the use of convenient antibiotic can decrease the speed of this bacteria resistance development.