Chlamydia pneumoniae eradication from carotid plaques.: Results of an open, randomised treatment study

Objective: to determine the effect of specific antibiotic treatment with roxithromycin in the eradication of Chlamydia pneumoniae from carotid artery plaques. Design: prospective open randomised treatment study. Patients and methods: we analysed 32 patients (16 females, mean age 70.1+/-14.7 years) who underwent surgery for the removal of atherosclerotic plaques from carotid arteries. During surgery samples of lingual vein and superior thyroid artery were also taken. Before surgery, patients were randomised to receive either roxithromycin 150 mg twice daily or no treatment. Sixteen patients were treated with antibiotic for a mean of 26 days (range 17-35 days). The two groups of patients were comparable in terms of age, sex, risk factors, and seroprevalence for C. pneumoniae. We applied a semi nested polymerase chain reaction (PCR) technique to the carotid plaques, lingual vein, and thyroid artery samples. Blood samples were obtained from the patients for the determination of C. pneumoniae IgG, IgA, and IgM antibody titres by a microimmunofluorescence technique. Results: in twelve out of sixteen non-treated patients we found evidence of C. pneumoniae DNA in the carotid plaques. Conversely, C. pneumoniae DNA was detected in only five out of sixteen treated patients (p = 0.034, Chi-squared test). In all cases PCA was negative for the lingual vein and thyroid artery samples. Conclusions: Roxithromycin seems effective in reducing the bacterial burden of C. pneumoniae within atherosclerotic plaques, although extended follow-up is needed to determine whether antibiotic treatment benefits long-term patient outcome.