Evaluation of Linezolid and Vancomycin in the treatment of Methicillin-Resistant Staphylococcus aureus(MRSA) in Cystic Fibrosis Patients

Abstract

Background: Cystic fibrosis (CF) patients often have pulmonary colonization with multiple organisms, including methicillin-resistant Staphylococcus aureus (MRSA), resulting in frequent hospitalizations and decreased quality of life. The pupose of this study was to evaluate the effectiveness of linezolid (LZD) and vancomycin (VAN) in the treatment of MRSA in the CF population. Methods: A prospective, pilot study was conducted in CF patients with pulmonary exacerbation and sputum culture positive for MRSA randomized to receive intravenous LZD or VAN. The primary endpoint was microbiological eradication of MRSA and secondary endpoints included Kanga Clinical Score and change in quality of life questionaire (CF QOL) score. Patients were followed for 6 months post treatment. The ability to conduct a comprehensive outcome protocol in this population at a children's hospital was also evaluated. Results: Eight subjects were randomized to receive LZD (n=5) or VAN (n=3), with average duration of therapy of 19.8 and 21 days, respectively. The primary endpoint of microbiological eradication at end of treatment (EOT) was achieved in 3 patients treated with LZD and 2 with VAN. Kanga Clinical Scores calculated at baseline and EOT showed a significant decrease in all subjects from a median of 26/50 to 16/50. Six patients or caregivers completed the CF QOL questionnaire. Five patients (2 treated with LZD, 3 with VAN) had improvements in CFQOL scores at EOT. No clinically significant adverse events were noted. Conclusions: VAN and LZD were clinically effective and well tolerated in the treatment of MRSA in our CF population. Eradication of MRSA was less likely in patients with long-standing infection. Comprehensive study protocols such as this may be utilized in a large, randomized controlled trial to determine standardized treatment for newly acquired MRSA in CF patients.