C pneumoniae causes pneumonia and bronchitis. The clinical presentation of pneumonia is that of an atypical pneumonia. The organism accounts for approximately 10% of community-acquired pneumonias, ranking second to mycoplasma as an agent of atypical pneumonia. A putative role in coronary artery disease has not been found upon careful scientific review.
Like C psittaci, strains of C pneumoniae are resistant to sulfonamides. Azithromycin, 500 mg orally on day 1 and 250 mg for 4 more days, or doxycycline, 100 mg orally two times a day for 10 days, appears to be effective therapy. Fluoroquinolones, such as levofloxacin (500 mg orally once daily for 7–14 days) or moxifloxacin (400 mg orally once daily for 7–14 days), are active in vitro against C pneumoniae and probably are effective. It is unclear if empiric coverage for atypical pathogens in hospitalized patients with community-acquired pneumonia provides a survival benefit or improves clinical outcome.
et al. Where is Chlamydophila pneumoniae
pneumonia? Respir Investig. 2020;58:336.