Ventilator-associated pneumonia caused by multidrug-resistant organisms or Pseudomonas aeruginosa: Prevalence, incidence, risk factors, and outcomes

Parker, Chris M.; Kutsogiannis, Jim; Muscedere, John; Cook, Deborah; Dodek, Peter; Day, Andrew G.; Heyland, Daren K.; for the Canadian Critical Care Trials Group,

doi:10.1016/j.jcrc.2008.02.001

« Previous Next »Journal of Critical Care
Volume 23, Issue 1 , Pages 18-26, March 2008

Ventilator-associated pneumonia caused by multidrug-resistant organisms or Pseudomonas aeruginosa: Prevalence, incidence, risk factors, and outcomes

Chris M. Parker, MD, MSc
- Department of Medicine, Queen's University, Kingston, Ontario, Canada K7L 2V7
Jim Kutsogiannis, MD, MHS
- Department of Critical Care, University of Alberta, Edmonton, Alberta, Canada T6G 2R3
John Muscedere, MD
- Department of Medicine, Queen's University, Kingston, Ontario, Canada K7L 2V7
Deborah Cook, MD, MSc
- Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada L8N 3Z5
Peter Dodek, MD, MHSc
- Center for Health Evaluation and Outcome Sciences, University of British Columbia, Vancouver, British Columbia, Canada V6Z 1Y6
Andrew G. Day, MSc
- Clinical Evaluation Research Unit, Kingston General Hospital, Kingston, Ontario, Canada K7L 2V7
Daren K. Heyland, MD, MSc
- Department of Medicine, Queen's University, Kingston, Ontario, Canada K7L 2V7
- Clinical Evaluation Research Unit, Kingston General Hospital, Kingston, Ontario, Canada K7L 2V7
- Corresponding author. Kingston General Hospital, Kingston, Ontario, Canada K7L 2V7. Tel.: +1 613 549 6666x3339; fax: +1 613 548 1351.
for the Canadian Critical Care Trials Group

Abstract

Purpose

The aim of this study was to clarify the prevalence and incidence of, risk factors for, and outcomes from suspected ventilator-associated pneumonia (VAP) associated with the isolation of either Pseudomonas or multidrug-resistant (MDR) bacteria (“high risk” pathogens) from respiratory secretions.

Materials and Methods

Data were collected as part of a large, multicentered trial of diagnostic and therapeutic strategies for patients (n = 739) with suspected VAP.

Results

At enrollment, 6.4% of patients had Pseudomonas species, and 5.1% of patients had at least 1 MDR organism isolated from respiratory secretions. Over the study period, the incidence of Pseudomonas and MDR organisms was 13.4% and 9.2%, respectively. Independent risk factors for the presence of these pathogens at enrollment were duration of hospital stay ≥48 hours before intensive care unit (ICU) admission (odds ratio, 2.37 [95% CI, 1.40-4.02]; P = .001] and prolonged duration of ICU stay before enrollment (odds ratio, 1.50 [95% CI, 1.17-1.93]; P = .002] per week. Fewer patients whose specimens grew either Pseudomonas or MDR organisms received appropriate empirical antibiotic therapy compared to those without these pathogens (68.5% vs 93.9%, P < .001). The isolation of high risk pathogens from respiratory secretions was associated with higher 28-day (relative risk, 1.59 [95% CI, 1.07-2.37]; P = .04] and hospital mortality (relative risk, 1.48 [95% CI, 1.05-2.07]; P = .05), and longer median duration of mechanical ventilation (12.6 vs 8.7 days, P = .05), ICU length of stay (16.2 vs 12.0 days, P = .05), and hospital length of stay (55.0 vs 41.8 days, P = .05).

Conclusions

In this patient population, the incidence of high-risk organisms newly acquired during an ICU stay is low. However, the presence of high risk pathogens is associated with worse clinical outcomes.

Keywords: Ventilator-associated pneumonia, ICU outcomes, Pseudomonas aeruginosa