Distribution of SCCmec Types in Methicillin-Resistant Staphylococcus aureus Isolated from Burn Patients

Abstract

Background: Methicillin resistance Staphylococcus aureus (MRSA) isolates have been recognized as one of the most important causes of infection in burn patients that have recently shown a frequent and rapid development of antibiotic resistance. Objectives: The present study described the distribution of different SCCmec types and antibiotic resistance pattern among MRSA strains isolated from burn patients in a referral burn center in Tehran, Iran. Methods: During a 12-month study, 189 MRSA isolates were obtained from burn patients. Standard culture and biochemical tests were used for identification of MRSA isolates. The antibiotic susceptibility testing was performed using disc diffusion method and the presence of mecA, nucA, pvl, and tst encoding genes was determined using PCR method. In addition, the different SCCmec types were determined using multiplex PCR. Results: All the MRSA isolates were observed to be resistant to amoxicillin and penicillin and sensitive to linezolid, teicoplanin, and vancomycin. The rates of resistance to other antibiotics varied from 86.2% for amikacin to 17.5% for quinupristin-dalfopristin. MDR was observed in all the isolates. Six different antimicrobial resistance patterns were observed among our isolates. Based on the multiplex PCR assay, the two different SCCmec types were detected as 71.4% type III and 28.6% type IV. In total, 8.5% of isolates harbored pvl toxin encoding gene all of which belonging to SCCmec type IV. Furthermore, 33 isolates (17.5%) harbored tst encoding gene. Conclusions: The results showed low diversity of SCCmec type among circulating MRSA in the burn center with relatively high prevalence of SCCmec III. These findings support the need for more studies to elucidate distribution of different SCCmec types among MRSA isolated from burn patients.