Abstract:
Background: Methicillin-resistant Staphylococcus aureus (MRSA) remains a major public health concern due to its association with increased morbidity, mortality, healthcare costs, and prolonged hospital stays. Epidemiological data on MRSA in Peru are limited and outdated. This study aimed to determine the frequency of MRSA, describe antimicrobial susceptibility patterns, and identify clinical factors associated with MRSA infection in a tertiary care hospital in Peru.
Methods: A retrospective observational study was conducted at a tertiary care hospital in Peru. Clinical isolates of S. aureus obtained from skin and soft tissue secretions (n=745), blood cultures (n=742), and osteoarticular samples (n=75) collected between 2016 and 2024 were analyzed. Antimicrobial susceptibility profiles were reviewed. Additionally, 215 medical records of patients with S. aureus infection were evaluated to identify demographic and clinical factors associated with MRSA infection.
Results: The overall frequency of MRSA was 37.2% (277/745) in skin and soft tissue secretions, 33.0% (245/742) in blood cultures, and 34.7% (26/75) in osteoarticular samples. In skin and soft tissue infections, MRSA prevalence remained relatively stable over time, ranging between 35% and 40%. Abscesses were the most frequent clinical presentation (330/745), followed by wound infections (169/745). Overall, S. aureus isolates showed high susceptibility to vancomycin (>97%), linezolid (>95%), rifampicin (>91%), and minocycline (>90%). The highest resistance rates were observed for erythromycin (50–53%) and clindamycin (43–49%). MRSA isolates exhibited lower susceptibility to erythromycin, clindamycin, gentamicin, and fluoroquinolones compared with methicillin-susceptible S. aureus (MSSA). However, trimethoprim-sulfamethoxazole (73.9–92.3%), minocycline (>95%), vancomycin (>96%), linezolid (>95%), and daptomycin (100%) maintained excellent activity against MRSA. The presence of comorbidities (OR=1.86; 95% CI: 1.05–3.31) and hospitalization during the previous year (OR=2.71; 95% CI: 1.52–4.84) were significantly associated with MRSA infection. No significant associations were found for the remaining clinical variables.
Conclusions: Approximately one-third of S. aureus isolates were identified as MRSA. Despite resistance to several antimicrobial classes, MRSA remained highly susceptible to vancomycin, linezolid, minocycline, and trimethoprim-sulfamethoxazole. Comorbidities and previous hospitalization were significant factors associated with MRSA infection and may contribute to risk stratification and empirical treatment decisions.
Biography:
I am Gonzalo Layza, a final-year medical student at the Universidad Peruana Cayetano Heredia in Lima, Peru. I have a strong academic interest in infectious diseases, with a focus on clinical understanding, prevention, and public health implications. Throughout his medical training, he has developed experience in hospital-based learning and patient care, and is particularly motivated to contribute to the study and management of communicable diseases in both local and global health settings.
