Prospective study of community-acquired pneumonia of bacterial etiology inadults

The aim of this study was to prospectively analyze the bacterial etiology o f community-acquired pneumonia in adults in Spain. From May 1994 to Februar y 1996, 392 episodes of CAP diagnosed in the emergency department of a 600- bed university hospital were studied. An etiological diagnosis based on non invasive microbiological investigations was achieved in 228 cases (58%); 17 3 of these diagnoses were definitive and 55 probable. Streptococcus pneumon iae, which caused 23.9% of the episodes, was the predominant pathogen obser ved, followed by Chlamydia pneumoniae (13.5%) and Legionella pneumophila (1 2.5%). Other less frequent pathogens found were Haemophilus influenzae (2.3 %), Pseudomonas aeruginosa (1.5%), Mycoplasma pneumoniae (1.3%), Coxiella b urnetii (1%), Moraxella catarrhalis (2 cases), Nocardia spp. (2 cases), and Staphylococcus aureus (2 cases). Streptococcus pneumoniae was significantl y more frequent in patients with underlying disease and/or age 60 years (28 % vs 13%, P = 0.002), while Legionella pneumophila was more frequent in pat ients below 60 years of age and without underlying disease (20% vs 9%, P = 0.006). Likewise, Streptococcus pneumoniae, and Legionella pneumophila were the most frequent etiologies in patients requiring admission to the intens ive care unit. occurring in 29% and 26.3% of the patients, respectively. In addition to Streptococcus pneumoniae. other microorganisms such as Chlamyd ia pneumoniae and Legionella spp. should be seriously considered in adults with community-acquired pneumonia when initiating empiric treatment or orde ring rapid diagnostic tests.