Nosocomial pneumonia in a Canadian tertiary care center: a prospective surveillance study

To determine the contribution of etiologic agents, including Legionella pneumophila and respiratory viruses to nosocomial pneumonia at a tertiary care center.

Prospective surveillance of nosocomial pneumonia with standardized laboratory investigations.

A 1,100-bed tertiary care center.

All adult inpatients.

One hundred and thirty-five Nosocomial pneumonias (5.7/1,000 discharges) were identified. Four (3.0%) were L pneumophila serogroup 1 infections (0.17/1,000 discharges). Legionellosis occurred in non-high-risk patients, and three cases would not have been identified without active surveillance. Viral seroconversion was identified in seven (19%) of 36 cases with specimens available (0.59/1,000 discharges): five influenza B, one influenza A, and one respiratory syncytial virus. IgM serology was positive in one case each for Mycoplasma pneumoniae and Chlamydia species. No geographical clustering was observed for viral infections, and these would not have been identified without active surveillance. Mortality for all nosocomial pneumonia was 25%. Patient factors significantly associated with a poorer outcome included older age, underlying disease, low serum albumin, renal insufficiency, lower platelet count, endotracheal intubation, respiratory failure, bacteremia, and use of antacids.

This prospective surveillance suggested that L pneumophila and viral agents were uncommon causes of nosocomial pneumonia at our institution during this surveillance period.