Effect of azithromycin on murine arteriosclerosis exacerbated by Chlamydiapneumoniae

Chlamydia pneumoniae infection can exacerbate atherosclerosis in animals. T o test the hypothesis that antibiotic therapy inhibits the atherogenic effe cts of C. pneumoniae infection, 10-week-old apolipoprotein E (ApoE) null mi ce were infected with C. pneumoniae or placebo, were treated for 2 weeks af ter infection with azithromycin or placebo, and were killed at 20 weeks of age. Infection did not affect the size of the aortic lesion, and antibiotic treatment had no effect. Another group of mice, 12-week-old ApoE mice, wer e infected with C. pneumoniae or placebo, were treated for 2 weeks after in fection with azithromycin or placebo, and were killed at 26 weeks of age. C . pneumoniae infection increased the size of the lesion in infected mice, b ut azithromycin did not reduce the size of the aortic lesion in infected mi ce. Therefore, immediate therapy of acute infection may be necessary to pre vent the proatherogenic effects of C. pneumoniae infection.