Bacteremic nosocomial pneumonia. A 7-year experience in one institution.

STUDY OBJECT: To describe the epidemiology, microbiology, and outcome of nosocomial pneumonia with secondary bloodstream infection. DESIGN: Prospective cohort study. SETTING: Tertiary care Canadian teaching hospital. PATIENTS: Inpatients. MEASUREMENT: All inpatient blood cultures were concurrently monitored over an 89 month period. Following chart review, patients experiencing nosocomial bloodstream infection due to pneumonia were identified. A standardized definition of pneumonia was used. RESULTS: One hundred forty-nine episodes occurred in 145 patients, 0.66/1,000 hospital admissions, 8.4% of all nosocomial bloodstream infections. No change in rate occurred in the study period. Fifty-four percent of episodes developed in one of seven ICUs. Staphylococcus aureus was the most frequently identified etiologic organism (27%). The ICU and non-ICU cases did not differ in etiology. No organism became more prevalent during the study period. Twenty percent of patients died within 1 week of first positive culture; episodes associated with Pseudomonas species had a much higher mortality rate (45%) than other infections (14%) (p = 0.002). The ICU and non-ICU infections had a similar mortality rate. CONCLUSION: Pneumonia is an important cause of nosocomial bloodstream infection, but it is not increasing in frequency or changing in etiology in our institution. The ICUs are a major contributor to this problem but have the same case short-term mortality rate and microbial etiology as non-ICU cases. Cases associated with Pseudomonas have a much higher mortality rate.