Community-acquired versus hospital-acquired methicillin-resistant Staphylococcus aureus in postoperative orthopaedic infections: A prospective observational study.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) remains a significant cause of postoperative orthopaedic infections worldwide. Differentiating community-acquired MRSA (CA-MRSA) from hospital-acquired MRSA (HA-MRSA) is critical for effective treatment, infection control, and public health planning. Objective: This study aimed to compare the prevalence, clinical profiles, antibiotic susceptibility patterns, and outcomes of CA-MRSA and HA-MRSA infections in postoperative orthopaedic surgical site infections (SSIs). Methods: A prospective observational study was conducted over 18 months in a tertiary care teaching hospital. Patients developing SSIs within 30 days after orthopaedic surgery were included. Wound swabs and pus samples were processed for culture and sensitivity testing. MRSA was identified by cefoxitin disc diffusion and mecA gene PCR. Cases were classified as CA-MRSA or HA-MRSA per CDC criteria. Clinical data, risk factors, antibiotic susceptibility, and outcomes were analysed. Results: Among 146 SSI cases, MRSA was isolated in 57 (39.0%), with 24 (42.1%) CA-MRSA and 33 (57.9%) HA-MRSA. HA-MRSA cases had higher rates of prior hospitalization (78.8% vs. 20.8%, p<0.001), previous antibiotic use (66.7% vs. 25.0%, p=0.002), and comorbidities. CA-MRSA isolates were more susceptible to clindamycin (87.5%) and trimethoprim-sulfamethoxazole (79.2%) compared to HA-MRSA (51.5% and 36.4%). All isolates were uniformly sensitive to vancomycin and linezolid. HA-MRSA infections were linked to longer wound healing and hospital stays (p=0.01). Conclusion: Both CA-MRSA and HA-MRSA contribute considerably to postoperative orthopaedic infections. HA-MRSA is more common and associated with worse clinical outcomes. Variations in susceptibility patterns highlight the importance of targeted empirical therapy and strict infection control measures. Recommendations: Implement routine MRSA typing, reinforce antibiotic stewardship, enhance preoperative screening, and strengthen hospital hygiene practices to reduce MRSA burden and improve patient outcomes.