Study objectives: To describe the causative organisms and factors associated with bacterial pneumonia and to assess its impact on the outcome of hospitalized patients with HIV.
Design: Prospective, observational.
Setting: A university-affiliated medical center.
Methods: We included 1,225 consecutive hospital admissions, from April 1995 through March 1998, of 599 adults with HIV. We collected data on APACHE II (acute physiology and chronic health evaluation II) score, leukocyte and CD4+ lymphocyte counts, length of hospital stay, ICU admission rate, and case-fatality rate. Chest radiographs and laboratory results were reviewed. The presence of bacterial pneumonia was noted.
Results: Bacterial pneumonia was diagnosed in 111 hospitalizations (9%): 80 (72%) were community-acquired infections. The CD4+ lymphocyte count was lower (median, 38 vs 66/microL, p = 0.0027), APACHE II score higher (17 vs 13, p < 0. 0001), length of hospital stay longer (median, 6 vs 4), and ICU admission (28% vs 9%) and case-fatality rates (21% vs 4%) higher in patients with bacterial pneumonia compared with those without bacterial pneumonia. The most common pathogen was Pseudomonas aeruginosa (32 admissions), followed by Streptococcus pneumoniae (22 admissions), Staphylococcus aureus (16 admissions), and Haemophilus influenzae (11 admissions). Thirty-three (30%) of the pneumonias were bacteremic. Bacteremia was more common in pneumococcal than in pseudomonal pneumonia (95% vs 9%, p < 0.0001). Compared with patients with pneumococcal pneumonia, patients with pseudomonal pneumonia had lower leukocyte and CD4+ lymphocyte counts, longer hospital stay, and similar case-fatality rate.
Conclusions: P aeruginosa is becoming a common cause of both community-acquired and nosocomial bacterial pneumonia in hospitalized patients with HIV, especially in those with low leukocyte and CD4+ lymphocyte counts.