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

Objective: to determine the effect of specific antibiotic treatment with ro xithromycin 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 plaque s from carotid arteries. During surgery samples of lingual vein and superio r 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 d ays). The two groups of patients were comparable in terms of age, sex, risk factors, and seroprevalence for C. pneumoniae. We applied a semi nested po lymerase chain reaction (PCR) technique to the carotid plaques, lingual vei n, and thyroid artery samples. Blood samples were obtained from the patient s 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 wa s detected in only five out of sixteen treated patients (p = 0.034, Chi-squ ared 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 p atient outcome.