بررسی فنوتیپ و ژنوتیپ مقاومت به موپیروسین در بین استافیلوکوک های مقاوم و حساس به متی سیلین جدا شده از عفونت های بیمارستانی

Background and purpose: Mupirocin is a topical antibiotic. This antibiotic can inhibit most of gram-positive cocci. Shortly after consuming the antibiotic mupirocin, resistance has emerged. The main purpose of this study was to determine mupirocin resistance in Staphylococcus strains isolated from nosocomial infections in the city of Arak. Material and Methods: A total of 150 Staphylococcus isolates (sensitive and resistant to methicillin S.aureus, coagulase negative staphylococcus) were subjected to the present study. In this study, 150 isolates of staphylococci were examined. PCR amplification of Sa442 gene was used as the identification marker for the confirmation of phenotypic diagnosis through biochemical and biological methods. In order to determine the presence of mecA gene in S. aureus isolates that were resistant to methicillin. All isolates were tested for mupirocin susceptibility by a disc diffusion method according to CLSI guideline. The minimum inhibitory concentration (MIC) was determined by an E-test and they were also analyzed by a PCR for the presence of ileS-1, mupA and mupB genes. Results: Among the 150 strains examined, 11 isolates were known resistant in disc diffusion and E-test. PCR result indicated that one isolate contains gene ileS-1, four isolates contain genes mupA and 6 strains containing both genes mupA and ileS-1. There was no strain that contained genes mupB and PCR results were fully consistent with the results of the E-test. Conclusion: This is a report of low frequency of mupirocin resistance in the city of Arak. This result illustrated that the prescription of mupirocin by physicians in this geographical region is limited. However, incorrect use can lead to rise in resistant rate. In addition, the combination of phenotypic methods and PCR for the detection of resistance to mupirocin is recommended.