Chlamydia pneumoniae infection in patients with cystic fibrosis.

The prevalence of atypical community-acquired infections as acute pulmonary exacerbations in patients with cystic fibrosis was prospectively studied. Thirty-two patients admitted to the hospital because of acute pulmonary exacerbations and 24 clinically stable patients seen for their routine visits were examined. The prevalence of infection with Chlamydia pneumoniae was assessed by culture and serology, and the presence of IgE to C. pneumoniae was studied by immunoblotting. A subgroup of patients was also examined for the presence of Mycoplasma pneumoniae infection. C. pneumoniae was isolated from four patients presenting with acute pulmonary exacerbations (12.5%) and from none of the stable patients; all patients for whom cultures were positive also had IgE to C. pneumoniae. Polymerase chain reaction analysis for M. pneumoniae was not positive for any patient, and only one patient with an acute exacerbation had an antibody titer compatible with a recent infection. We conclude that infection with C. pneumoniae is associated with acute pulmonary exacerbations in some patients with cystic fibrosis and that it may trigger the production of IgE specific to C. pneumoniae, thus leading to bronchial reactivity in these patients.