Detection of Methicillin-resistant Staphylococcus aureus according to mecA and femA Genes Among Hospitalized Patients in Kashan and Isfahan Hospitals

Increased prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and treatment of infections due to these resistant strains is one of the most important health challenges. In this study, antimicrobial resistance patterns of Staphylococcus aureus isolates from patients were determined to commonly prescribed and last-resort antibiotics, and methicillin-resistant Staphylococcus aureus strains were isolated according to detection of mecA and femA genes.

This research was done on 146 Staphylococcus aureus isolates from hospitalized and outpatients who referred to Isfahan Hospitals and Shahid-Beheshti Hospital of Kashan from June 2017 to September 2018. Antimicrobial resistance patterns to common antibiotics were determined by disk diffusion method according to the Clinical and Laboratory Standards Institute (CLSI) 2018 guidelines. Also Vancomycin minimum inhibitory concentration (MIC) of MRSA strains was determined using broth microdilution method. Isolation of MRSA strains were phenotypically done using cefoxitin disk and for confirmation mecA and femA genes were detected in these strains.

From 146 collected clinical samples, frequencies of MRSA and methicillin-susceptible Staphylococcus aureus (MSSA) were 24 (16.4%) and 122 (83.6%) respectively. The most resistance rate were detected to erythromycin 44 (30.1%) and vancomycin resistance was not seen among the S. aureus isolates, whereas linezolid resistance was 2/1 percent. In molecular study using PCR method, all MRSA strains carried mecA and femA genes.

Current study showed that the frequency of MRSA among clinical samples isolated from Isfahan and Kashan Hospitals is relatively high. Also the presence of resistance to new and important antibiotics as last resort treatment is considered a serious alarm.