Breakthrough pneumococcal bacteremia in patients being treated with azithromycin and clarithromycin

Streptococcus pneumoniae strains have exhibited decreasing susceptibility t o penicillins and macrolides during the past several years. We reviewed the medical charts of all patients with pneumococcal bacteremia who were admit ted to a university hospital over a period of 1 year, to identify failures of outpatient therapy. Of 41 patients admitted with pneumococcal bacteremia , 4 had previously taken either azithromycin or clarithromycin for 3-5 days . All 4 had pneumococcal strains that exhibited low-level resistance to mac rolide antibiotics. Among pneumococci, low-level resistance to macrolides c an lead to clinical failure, and resistance to macrolides should be conside red during the selection of empiric therapy for patients with presumed pneu mococcal infections.