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

Abstract

Background: 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. Objectives: 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. Methods: 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. Results: 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. Conclusions: Precise epidemiological monitoring of integrons is required to prevent mupirocin resistance dissemination in MRSA strains.