BACKGROUND AND OBJECTIVE: Mupirocin is a secretory antibiotic and a bacterial Isoleucine- tRNA synthetase enzyme inhibitor which is used against impetigo. Mupirocin specifically binds to Isoleucine-tRNA synthetase enzyme and inhibits protein synthesis. The aim of this study was to prepare standard strains of Staphylococcus aureus with a designated and approved molecular genetic map from iles-1 gene using AluI enzyme.

METHODS: In this cross-sectional study, 150 clinical strains of Staphylococcus aureus isolated from skin samples of patients and staff in three hospital of Qom, from transfer medium (BHI) (Merck, Germany) on blood agar medium (Merck, Germany) using streak plate method and cultured for 24 to 48 hours and were incubated at 37°C. Using biochemical and PCR methods, srRNA 16 area was validated. Presence of Iles-1 gene was considered using PCR and mapping of AluI enzymatic digestion was carried out. Also 5ug mupirocin disk was used to investigate bacterial resistance.

FINDINGS: The results showed that from150 samples, 7 samples are mupirocin resistant strains. The rate of infection with resistant strains in women was 42.58% and men 57.14%, respectively. 100% of resistant isolates to mupirocin had a positive PCR for iles-1 gene of resistant to chromosomal mupirocin.

CONCLUSION: It is concluded that mupirocin resistant strains of Staphylococcus aureus is few.