RISK-FACTORS FOR NOSOCOMIAL LEGIONELLA-PNEUMOPHILA PNEUMONIA

Over a 5-yr period, from January 1985 to January 1990, we prospectivel y studied 300 episodes of nosocomial pneumonia in a 1,000-bed teaching hospital. All cases had an accurate bacteriologic diagnosis obtained by means of highly reliable techniques. Legionella pneumophila caused a total of 36 episodes; 22 were endemic and 14 occurred during an epid emic outbreak. No patient with Legionella pneumonia had been intubated before infection. To identify risk factors for nosocomial L. pneumoph ila pneumonia, we compared the 22 endemic cases of nosocomial pneumoni a due to L. pneumophila with the 264 cases due to other bacteria. Afte r adjusting for other variables by means of logistic regression analys is, cytotoxic chemotherapy(OR = 5.2; 95% Cl, 1.5 to 17.9) and use of c orticosteroids (OR = 4.6; 95% Cl, 1.5 to 14.1) were positively associa ted with L. pneumophila pneumonia, whereas previous antibiotic therapy (OR = 0.2; 95% Cl, 0.1 to 0.8) and lowered consciousness (OR = 0.2; 95 % Cl, 0.07 to 0.8) were negatively associated. The major risk factors for Legionella pneumonia delineated in this study should be considered in the clinical approach to and empiric therapy of patients with susp ected nosocomial pneumonia.