Community-acquired respiratory tract infections caused by resistant pneumococci: clinical and bacteriological efficacy of the ketolide telithromycin

The incidence of community-acquired respiratory tract infections caused by Streptococcus pneumoniae exhibiting antibacterial resistance has increased dramatically in recent years. Telithromycin is the first of a new class of antibacterials, the ketolides, which have been developed specifically to provide effective treatment for these infections. Data were analysed from 3935 patients who had participated in one Japanese Phase II study and 11 US/global Phase III studies in three indications: community-acquired pneumonia, acute exacerbations of chronic bronchitis or acute sinusitis. Patients received either telithromycin 800 mg once daily or a comparator antibacterial. S. pneumoniae isolates considered to be causative for infection were tested for susceptibility to penicillin G and erythromycin A. In per-protocol analyses, telithromycin showed a high level of clinical efficacy against S. pneumoniae, with clinical cure rates of 92.8% for all isolates, 91.7% for those with reduced susceptibility to penicillin G and 86.0% for those with reduced susceptibility to erythromycin A. Bacterial eradication rates were consistent with the clinical outcomes. High rates of clinical cure and bacterial eradication were also observed for infections caused by isolates demonstrating high-level resistance to erythro-mycin A [MICs ≥ 512 mg/L: 100% (13/13) clinical cure, 100% (13/13) bacterial eradication]. These results support the use of telithromycin as a first-line oral therapy for the treatment of community-acquired respiratory tract infections caused by S. pneumoniae with reduced susceptibility to penicillin G and erythromycin A.