Combined retrospective analysis of seven phase II and III trials of the efficacy of linezolid in the treatment of pneumonia caused by multidrug-resistant Streptococcus pneumoniae

Background: Antimicrobial resistance among Streptococcus pneumoniae is of concern. Up to 30% of pneumococcal isolates worldwide are multidrug resistant.Objective: The objective of this analysis was to assess the effectiveness of linezolid for the treatment of pneumonia caused by S pneumoniae, including multidrug-resistant S pneumoniae (MDRSP).Methods: Data from 7 Phase II and III clinical trials that assessed the efficacy of linezolid in community- or hospital-acquired pneumonia were pooled. Adults and children (aged ≤12 years) received linezolid 600 mg and 10 mg/kg, respectively, IV or PO q12h for 7 to 14 days, with the exception of patients with documented bacteremia who could be treated for up to 28 days. Patients with a confirmed baseline isolate of S pneumoniae, including MDRSP, were assessed for clinical and microbiological outcomes. MDRSP was defined as an isolated strain of S pneumoniae that was resistant to ≥3 classes of antibiotics. Clinical cure was defined as the resolution of clinical signs and symptoms of pneumonia compared with baseline, with either improvement or absence of progression of abnormalities on chest radiography. Microbiological eradication was defined as documented or presumed eradication at the test-of-cure (TOC) visit. Results from patients with indeterminate or missing outcomes at TOC were not included in the analyses.Results: Of the patients with no bacteremia and treated with linezolid, 19 adults had MDRSP and 165 had non-MDRSP, and 3 children had MDRSP and 7 had non-MDRSP. Clinical cure and microbiological eradication rates were not significantly different between those infected with an MDRSP or non-MDRSP pathogen, respectively, in adults (16/19 [84%] and 150/164 [91%]) and children (3/3 [100%] and 7/7 [100%]).Conclusion: Linezolid was efficacious for the treatment of pneumonia caused by S pneumoniae, including multidrug-resistant strains.