The Detection of Mupirocin Resistance and Nasal Carriage of Methicillin Resistant Staphylococcus aureus among Healthcare Workers at University Hospitals of Tehran, Iran

Nasal mupirocin is found to eradicate effectively methicillin-resistant Staphylococcus aureus (MRSA) from colonized patients, but there are concerns about resistant strains. The aim of this study was to detect the mupirocin resistance and nasal carriage of methicillin resistant S. aureus among healthcare workers (HCWS) at the university hospitals of Tehran. Totally 270 nasal swabs were collected and S. aureus were identified by confirmatory tests in 2013. Determination of oxacillin and mupirocin resistance was performed by disk diffusion method and the mupirocin MIC assessed using E-test. The ileS-2 (mupA) and mecA genes were detected in DNA extracts by multiplex PCR. The prevalence of S. aureus nasal carriage among HCWs was 14.44%. E-test and disk diffusion methods showed 5 and 4 mupirocin resistant isolates, respectively. Statistically significant difference was observed between sex (P=0.035), hospitals (P=0.0001) and occupation (P=0.009) with nasal carriage of S. aureus. A significant difference was found between sex (P=0.041) and occupation (0.034) with regard to MRSA carriage. All MRSA isolates were susceptible to linezolid, fusidic acid and vancomycin. Since the HCWs play an important role as a reservoir for resistant isolates in the hospital setting, regularly screening should be performed for identification of nasal carriers.