Prevalence, diversity, and antimicrobial susceptibility profiles of methicillin- resistant Staphylococcus aureus among patients with diabetic foot infections in a referral hospital in Tehran, Iran

Abstract

Abstract The increasing incidence of methicillin-resistant Staphylococcus aureus (MRSA) is a major problem in the treatment of diabetic foot infections (DFIs). Due to the evolution of MRSA clones, and thereby inappropriate antibiotic therapy, typing of these strains in DFIs is needed to reduce their clonal dissemination in different regions. This study aimed to determine the prevalence, diversity, and antibiotic susceptibility profiles of MRSA isolated from patients with DFIs attending a referral hospital in Tehran, Iran during 2019–2020. Staphylococcal cassette chromosome mec (SCCmec) typing, ccr typing, PhP typing, and detection of Panton-Valentine Leukocidin (pvl) gene were done to explore the diversity of the strains. Antibiotic susceptibility profiles of the strains were also determined using the disk diffusion method and broth microdilution assay. Of the 238 S. aureus strains isolated, 73 were identified as MRSA. The highest antibiotic resistance was seen against ciprofloxacin (86%), followed by kanamycin and tobramycin (84%). Overall, MRSA strains were categorized into 29 antibiotypes. Also, 49.3% of strains were known as high-level oxacillin-resistant strains (MIC ≥ 256 µg/ml). SCCmec type III and type 3 ccr were detected in 86.3% of strains and they were classified as hospital-acquired (HA)-MRSA. PhP typing revealed the presence of 8 common types (CTs) and 11 single types (STs), with CT2 comprising 41.1% of the strains. Our data suggest that MRSA strains isolated from DFIs in this country could be diverse and resistant to clinically important antibiotics. In this context diabetic patients can serve as a reservoir for dissemination of these bacteria between community and clinical environments.