A Frequency and Molecular Typing Study of Methicillin-Resistant Staphylococcus aureus Isolates in Teaching Hospitals in Shahrekord, SouthWestern Iran

Background: Methicillin-resistant Staphylococcus aureus (MRSA) remains a significant public health problem and treatment challenge. Objectives: This study was conducted to determine the frequency, molecular types, and drug resistance of S. aureus isolated from nasal carriers in two teaching hospitals (Hajar and Kashani) in Shahrekord, southwestern Iran. Methods: In this cross-sectional study, 262 nasal specimens were obtained from healthcare staff. The disk-diffusion method was used to detect MRSA. Nine antibiotic disks were used to determine the antibiotic susceptibility pattern. Staphylococcal cassette chromosome mec (SCCmec) types were identified by the multiplex polymerase chain reaction (PCR). The data analysis was performed using Fisher's exact test with SPSS software. Results: Forty-eight (18.8%) specimens were identified as S. aureus, of which 30 (11.45%) specimens were methicillin resistant. The nasal colonization rate of the MRSA isolates was not associated with age or gender (P > 0.05). The highest resistance (33%) recorded was to rifampin, and all the isolates were susceptible to quinupristin-dalfopristin, vancomycin, and linezolid. The SCCmec results showed that 16.7%, 6.7%, 20%, and 56.6% of MRSA isolates were types I, II, III, and IV, respectively. Conclusions: Nasal isolates of MRSA were prevalent among hospital staff. The highest level of resistance was to rifampin, and all the isolates were susceptible to quinupristin-dalfopristin, vancomycin, and linezolid. SCCmec type 4 was the most frequent MRSA isolate.