The growing problem of antibiotic resistance of respiratory pathogens causing community-acquired pneumonia (CAP), in particular Streptococcus pneumoniae, greatly complicates the choice of empirical therapy for this nosological form. An open, non-comparable study in 3 university clinics in Japan evaluated the efficacy and tolerability of a 3-day course of azithromycin in adult patients with mild to moderate community-acquired pneumonia and investigated the hypothesis of resistance of pneumococci to macrolides in vitro to the clinical ineffectiveness of therapy.

Patients were considered suitable for inclusion in the study if they were diagnosed with mild or moderate severe community-acquired pneumonia and were 18 years of age or older. All patients received azithromycin 500 mg / day for 3 days. The clinical and microbiological efficacy of the therapy was evaluated 1 and 2 weeks after the start of treatment.

In the study, 78 patients received treatment, of which 59 people had enough data to analyze the effectiveness of treatment. In general, a positive clinical response to treatment was observed in 49 patients (83.1%) and a microbiological response was obtained in 78.3% of cases.

Resistance of pneumococci to azithromycin based on CLSI criteria was observed in 85.7% of S. pneumoniae (12/14), and the presence of ermB genes was detected in 50 % of isolates (7/14). However, in patients in whom S. was isolated pneumoniae (n = 17), a clinical response to treatment was obtained in 76.5% of the cases (13/17 patients) and a microbiological response in 64.3% (9/14). In addition, in 6 out of 7 patients with CAP caused by strains of high-resistance pneumococci (BMD greater than 256 μg / ml and presence of ermB genes), a satisfactory clinical response to treatment was observed.

Tolerance to azithromycin was good: adverse events (mainly from the gastrointestinal tract) were reported in 6 patients (7.7%).

Thus, most patients with community-acquired pneumonia have a good response to treatment with azithromycin. In addition, azithromycin may be effective in community-acquired pneumonia caused by macro-resistant strains S. pneumoniae, however, large-scale studies are needed to confirm this point.