Acute purulent exacerbation of chronic obstructive pulmonary disease and Chlamydia pneumoniae infection

In order to investigate the role of bacteria, including Mycoplasma pneumoni ae and especially Chlamydia pneumoniae in acute purulent exacerbations of c hronic obstructive pulmonary disease (COPD), we examined sputum specimens a nd acute and convalescent sera taken 26 d apart from 49 outpatients experie ncing an acute purulent exacerbation of COPD. The sera were tested for anti bodies to C, pneumoniae with the microimmunofluorescence test, and for anti bodies to M. pneumoniae with the indirect fluorescence antibody test. Routi ne microbiologic culture of sputum yielded potentially pathogenic microorga nisms in 12 of the 49 patients (24%). Three patients (6%) showed serologic evidence of recent M. pneumoniae infection. Seven patients showed high IgG titers of greater than or equal to 1:1,024 to C. pneumoniae, and an additio nal four had a fourfold increase in IgG titer, suggesting reinfection with C. pneumoniae. Sputum from two of these 11 patients also grew Streptococcus pneumoniae, and one grew Moraxello cotarrhalis. Patients with and without serologic evidence of current C. pneumoniae infection showed no significant differences in clinical features or pulmonary function. The high incidence of infection with C, pneumoniae (the sole causal agent in 16% of cases, an d the causal agent with other agents in 6%) provides insight into the impor tance of this organism among agents leading to exacerbations of COPD in Tur key.