Outcomes of Treatment for Methicillin-Resistant Staphylococcus aureus Ventilator-Associated Pneumonia

Objective: Ventilator-associated pneumonia (VAP) due to methicillin-resistant Staphylococcus aureus (MRSA) remains a therapeutic challenge. Vancomycin is the recommended first-line therapy; however, trimethoprim-sulfamethoxazole (SMX-TMP) presents a potential alternative due to its pharmacokinetic properties and cost-effectiveness. Clinical data supporting its use in VAP are limited. The aim of this study was to compare the clinical outcomes of patients with MRSA-VAP treated with SMX-TMP versus vancomycin. Methods: We conducted a retrospective, single-center, cross-sectional study between January 2020 and July 2021 at a tertiary academic hospital in southern Brazil. Adult patients with confirmed MRSA-VAP and documented susceptibility to both SMX-TMP and vancomycin were included. The primary outcome was in-hospital mortality. Secondary outcomes included clinical response at day 5, ICU and hospital length of stay, and VAP duration. Statistical comparisons were made using chi-square and t-tests, with significance set at p < 0.05. Results: A total of 125 patients were analyzed (vancomycin: n=60; SMX-TMP: n=65). Mortality was 37% in the vancomycin group versus 28% in the SMX-TMP group ( p = 0.285). Clinical cure at day 5 was similar (52% vs. 55%, respectively). No significant differences were observed in SOFA scores, ICU or hospital stay, or VAP duration between groups. Conclusion: SMX-TMP was associated with clinical outcomes comparable to vancomycin in patients with MRSA-VAP. These findings suggest SMX-TMP may represent a viable therapeutic alternative in selected patients. Further prospective studies are warranted to validate its role in this context.