PHENOTYPIC AND GENOTYPIC CHARACTERIZATION OF ANTIBIOTIC RESISTANCE AMONG METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS ISOLATES IN PATIENTS ADMITTED TO ISFAHAN AND KASHAN HOSPITALS IN2017

Background and Aim:Background and Aim: Staphylococcus aureus is the most important human pathogen, which has become a concern as a result of its increasing resistance to various antimicrobials. The aim of this investigation was characterization of antimicrobial resistance pattern among methicillin-resistant Staphylococcus aureus isolated from patients clinical specimens in Isfahan and Kashan hospitals.Methods:This cross-sectional study was conducted on 140 patients hospitalized in ICU, surgical, heart, infectious and emergency departments in Isfahan and Kashan hospitals. The resistance pattern of isolates was determined using disc diffusion and D- test methods according to CLSI guidelines. The antibiotics used included cefoxitin, cefazolin, erythromycin, clindamycin, linzolid, and trimethoprim-sulfamethoxazole. All isolates were screened for the presence of femA and mecA genes by PCR assay.Results:All methicillin-resistant Staphylococcus aureus isolates were confirmed by PCR method using femA and mecA genes. The results showed of all isolates, 24, 13, 3 and 11 methicillin-resistant Staphylococcus aureus isolates were cefoxitin, cefazolin linzolid and trimethoprim-sulfamethoxazole –resistant respectively. Phenotypic and genotypic characterization of antibiotic resistance among methicillin-resistant Staphylococcus aureus isolates in patients admitted to Isfahan and Kashan hospitals. 7 isolates D_shaped clear zone around CLSI disk proximal erythromycin disk,13 isolates D_shaped zone around CLSI disk proximal to the erythromycin disk and small colonies, growing to CLSI in otherwise clear zone.Conclusion:The increasing resistance in methicillin-resistant Staphylococcus aureus isolates even to last resort antibiotics, such as linzolide, can be a serious threat to human health and society.

کلیدواژه ها:

Staphylococcus aureus ، antibiotic resistance ، D- test ، femA ، mecA