THE ETIOLOGY OF COMMUNITY-ACQUIRED PNEUMONIA AMONG HOSPITALIZED-PATIENTS DURING A CHLAMYDIA-PNEUMONIAE EPIDEMIC IN FINLAND

The etiology of community-acquired pneumonia during a Chlamydia pneumo niae epidemic was studied among 125 hospitalized patients. Etiologic i nvestigations included blood and sputum cultures, pneumococcal antigen detection, and serologic investigations for common respiratory viruse s and for Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Mycoplasma pneumoniae, and Chlamydia species. A specific microbial agent was identified in 110 patients (88%). Some 48% of the patients had mixed infections, S. pneumoniae was the most common patho gen (55%), followed by C. pneumoniae (43%). C. pneumoniae was found bo th as a single etiologic agent and as a mixed infection, most often wi th S. pneumoniae. In conclusion, S. pneumoniae is the most common caus e of community-acquired pneumonia, even during a C pneumoniae epidemic . The organism, alone or with other pathogens (especially S. pneumonia e), may cause community-acquired pneumonia that requires hospital trea tment.