Clinical and Demographic Correlates of MRSA and mecA-Positive Isolates in a Tertiary Hospital, Tehran: A Cross-Sectional Study

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of healthcare- associated infections, with the mecA gene serving as a key marker of resistance. This study investigates the clinical and demographic factors associated with MRSA and mecA carriage in a tertiary hospital in Tehran to inform targeted infection control strategies.. Methods: This cross-sectional study included 125 hospitalized patients with Staphylococcus aureus infections from a tertiary hospital in Tehran. Clinical and demographic data were collected via structured questionnaires and medical records, and MRSA/mecA status was determined using phenotypic methods and real-time PCR, with associations analyzed using chi-square and Fisher’s exact tests in SPSS v18.. Results: MRSA was identified in 40.8% of Staphylococcus aureus isolates, with no significant association found with age or sex. Prolonged hospitalization, immunocompromised status, and frequent antibiotic use were significantly associated with MRSA infection (p < 0.05), while a lower prevalence was observed among patients with infected wounds. Conclusion: This study highlights a high prevalence of MRSA in a Tehran tertiary hospital, with prolonged hospitalization, immunocompromised status, and antibiotic overuse identified as key risk factors. Targeted infection control strategies integrating clinical risk assessment and microbiological surveillance are recommended to mitigate MRSA transmission.