? ORIGINAL ARTICLE? Efficacy of Azithromycin in the Treatment of Community- acquired Pneumonia, Including Patients with Macrolide- Resistant Streptococcus pneumoniae Infection

Background and Objective The growing problem of drug resistance among respiratory pathogens in community-acquired pneumonia (CAP), particularly Streptococcus pneumoniae, (S. pneumoniae) has compli-cated initial empiric therapy of CAP. This study was undertaken to evaluate the efficacy and tolerability of a 3-day course of azithromycin in adults with mild to moderately severe CAP, and to determine whether in vi-tro macrolide resistance among strains of S. pneumoniae is related to clinical efficacy/failure. Methods An open-label, non-comparative study was undertaken at 3 university-affiliated hospitals in Japan. Patients were eligible if they were 18 years or older and had mild or moderately severe CAP. All patients re-ceived azithromycin 500 mg/day for three days, and clinical and microbiological responses were evaluated 1 and 2 weeks after initiating therapy. Results A total of 78 patients received the study medication, 59 of whom had sufficient data available for efficacy analysis. Overall, a good clinical response with azithromycin was achieved in 49 patients (83.1%) and a microbiological response was achieved in 78.3%. Azithromycin resistance, based on CLSI criteria, was demonstrated in 85.7 % (12/14) of S. pneumoniae isolates, and the presence of ermB genes was found in 50.0 % (7/14). However, among patients in whom S. pneumoniae was isolated (n=17), a good clinical re