Patients and Methods
From February 1988 to May 1989 all patients with community-acquired pneumonia who required hospitalization were prospectively studied. Criteria for admission included age greater than 60 years old, underlying disease, severely ill, respiratory failure, presence of cavitation, pleural effusion or diffuse infiltrates evidenced on die chest roentgenogram.
For each patient we recorded clinical and routine laboratory data, chest roentgenogram and arterial blood gas value levels when there were signs of respiratory failure. Sputum specimens were cultured for bacteria only if >25 polymorphonuclear leukocytes and <10 squamous epithelial cells were present per low-power field on the Gram stain (group 5 of Murray and Washington criteria). Quantitative sputum culture with a gauged handle was done in all these cases. Sputum specimens were cultured in BCYE-alpha media in all cases. Cultures in BCYE-alpha media were done by direct inoculation of 25 g/L of a commercial Legionella CYE agar-base (Oxoid SR 110) with 10 g/L ACES, 3 g/L alpha-ketoghitaric add, 3 g/L lysine, 0.4 g/L L-cysteine, 0.25 g/L ferric pyrophosphate, 80 min/L cydoheximide, 11 mg/L polymyxin and 1 mg/L vancomycin.