A retrospective study to evaluate the efficiacy of trimethoprim/sulfamethoxazole (TMP/SMX) compared to daptomycin or linezolid for the treatment of infections due to methicillin-resistant staphylococcus aureus (MRSA)

Aparna Lakshmi Poona Murari


Background: Staphylococcus aureus is still considered one of the most significant human pathogens in terms of morbidity, mortality, and costs. Vancomycin should be avoided if possible for the treatment of MRSA when the Minimum Inhibiting Concentration (MIC) to Vancomycin is 2μg/mL, as it poses a therapeutic challenge. Main therapeutic options include Daptomycin and Linezolid, two new, expensive drugs, and trimethoprim/sulfamethoxazole(TMP/SMX), an old, inexpensive agent. Study aims were to compare the clinical efficacy and potential cost savings associated with TMP/SMX use. Methods: A retrospective study was conducted at Detroit Medical Center. For calendar year 2009, unique adult patients (>18 years) with infections due to MRSA with MIC to Vancomycin of 2 μg/mL were included if they received ≥2 doses of TMP/SMX and/or Daptomycin and/or Linezolid. Data were abstracted from patient charts and pharmacy records. Results: There were 328 patients included in study cohort; 143 received TMP/SMX alone, 89 received Daptomycin alone, 75 received Linezolid alone, and 21 patients received a combination therapy. In bivariate analysis, patients on TMP/SMX had significantly better outcomes, including in-hospital (p=0.003) and 90-day mortality (p