Molecular Analysis and Integron Carriage of Mupirocin-Resistant Staphylococcus aureus Strains Isolated from Burn Wound Infections, Tehran, Iran

The prevalence of wound infections associated with multidrug-resistant Staphylococcus aureus (S. aureus) strains among burns patients has tremendously increased. Recently, the role of integrons as a key system involved in spreading multi-drug resistance has been well documented. To investigate the prevalence of integrons, antimicrobial resistance pattern, and S. aureus protein A (spa) typing of the mupirocin-resistant S. aureus (MRSA) strains obtained from a referral burns hospital in Tehran, Iran. This study was performed during January 2017 to April 2018 on 64 MRSA isolates gathered from burns patients. The isolates were examined for susceptibility to antimicrobial agents. The integrase-encoding gene was detected by conventional polymerase chain reaction (PCR). Integrase-positive strains were evaluated for the determination of integron classes by using PCR-restriction fragment length polymorphism assay, and genotyping was performed by spa typing. Out of 64 MRSA strains, 24 (37.5%) and 40 (62.5%) isolates carried high-level and low-level resistance, respectively. The findings revealed that the entire isolates were MRSA. They belonged to six different spa types including t860 (40.6%), t790 (21.8%), t037 (17.2%), t064 (17.2%), t008 (1.6%), and t631 (1.6%). Class 1 and 2 integrons were found in 59.4% and 17.2% of the isolates, respectively, and 4 (6.2%) isolates were observed to carry class 1 and 2 integrons simultaneously. Precise epidemiological monitoring of integrons is required to prevent mupirocin resistance dissemination in MRSA strains.