Abstract
Background
Staphylococcus aureus (S. aureus), particularly methicillin-resistant S. aureus (MRSA), is a major human pathogen causing severe infections. While well studied in hospitals, limited data exist on the transmission and antimicrobial resistance (AMR) profiles of community-associated MRSA (CA-MRSA) in the Gulf region. This study investigated the AMR patterns of CA-MRSA.Methods
Nasal and axillary swabs from 576 asymptomatic residents of Qatar without a history of hospitalization, surgery, dialysis, or indwelling medical devices in the preceding 12 months, and those who have not used antibiotics within the previous 3 months were analyzed. S. aureus was isolated on mannitol salt agar, confirmed by VITEK® 2 Compact, and methicillin resistance was determined by cefoxitin disc diffusion. AMR profiling followed CLSI guidelines. PCR and whole-genome sequencing using the GridION platform were performed for molecular confirmation and genomic characterization, including gene annotation and phylogenetic analysis. All sequences were deposited in NCBI.Results
Of 60 confirmed S. aureus isolates (10.4% prevalence), 35% (n = 21) were MRSA, yielding an overall MRSA carriage prevalence of 3.6% (21/576). Most MRSA isolates came from young asymptomatic individuals aged 18 to 45 (80%, 17/21) and from men (58%, 12/21). Among the 21 MRSA isolates identified in this cohort, resistance rates were 29% for erythromycin and ciprofloxacin, 24% for tetracycline, 14% for gentamicin, and 10% for sulfonamides. A total of 71% of the isolates exhibited multidrug resistance. All MRSA isolates carried the methicillin resistance gene (mecA), while 4.7% harbored the Panton-Valentine leukocidin (PVL) gene. Phylogenetic analysis revealed four distinct clusters, indicating a polyclonal community rather than a single spreading strain.Conclusions
The prevalence of multidrug-resistant MRSA with key virulence factors may represent a continuing public health concern, underscoring the need for strengthened community surveillance, antimicrobial stewardship, and infection control to monitor and limit the spread of multiple circulating strains.