Effect of azithromycin plus rifampin versus amoxicillin alone on eradication and inflammation in the chronic course of Chlamydia pneumoniae pneumonitis in mice

Abstract

The effects of treatment with azithromycin plus rifampin (A+R), amoxicillin (A), or placebo (P) on the chronic course of experimental Chlamydia pneumoniae pneumonitis in mice were assessed by culture, PCR, and immunocytochemistry as well as by degree of inflammation in lung tissue. Eradication of the pathogen was significantly more frequent and inflammation in tissue was significantly reduced after treatment with A+R compared to after treatment with A or P. Combination therapy with azithromycin plus rifampin showed favorable effects in the chronic course of C. pneumoniae pneumonitis.

FIG. 1

Number of nodular mononuclear infiltrates in sections of lung tissue 30 and 60 days after infection. Each dot represents data from one animal. Three treatment regimens were studied, as follows: amoxicillin (Amoxi) (20 mg/kg s.c. b.i.d. for 7 days), azithromycin (10 mg/kg s.c. daily for 5 days) plus rifampin (20 mg/kg s.c. bid for 7 days) (Azi + Rif), and PBS (b.i.d. for 7 days). Statistical comparisons were done by Mann-Whitney test.