Increased mortality of ventilated patients with endotracheal Pseudomonas aeruginosa without clinical signs of infection.
OBJECTIVE
To investigate the frequency and outcomes of ventilated patients with newly acquired large burdens of Pseudomonas aeruginosa and to test the hypothesis that large quantities of bacteria are associated with adverse patient outcomes.


METHODS
A prospective, single-center, observational, cohort study.


METHODS
Medical-surgical intensive care units in a tertiary care university hospital.


METHODS
All adult patients requiring > or = 48 hrs of mechanical ventilation and identified as having newly acquired P. aeruginosa in their lower respiratory tracts between October 2002 and April 2006.


METHODS
None.


RESULTS
Daily surveillance cultures of endotracheal aspirates were performed on patients intubated > or = 48 hrs; 69 patients with newly acquired P. aeruginosa were enrolled. Daily P. aeruginosa quantification of endotracheal aspirates was performed; clinical signs of infection were noted. Of 45 patients with high P. aeruginosa burdens (> or = 1,000,000 colony-forming units/mL in endotracheal aspirates; > or = 10,000 colony-forming units/mL in bronchoalveolar-lavage), 17 (37.8%) patients did not meet clinical criteria for ventilator-associated pneumonia and had a statistically significant higher risk of death (adjusted hazard ratio, 37.53; 95% confidence interval, 3.79-371.96; p = 0.002) when compared with the patients who had P. aeruginosa ventilator-associated pneumonia. When excluding the ten patients who had ventilator-associated pneumonia attributed to bacteria other than P. aeruginosa or attributed to multiple bacteria including P. aeruginosa, the risk of death remained statistically significant (adjusted hazard ratio, 23.98; 95% confidence interval: 2.49-230.53; p = 0.006). Furthermore, more patients with high P. aeruginosa burdens secreted the type III secretion facilitator protein, PcrV (p = 0.01).


CONCLUSIONS
A group of patients with large burdens of P. aeruginosa who did not meet clinical criteria for ventilator-associated pneumonia had an increased risk of death when compared with patients who had high P. aeruginosa burdens and met ventilator-associated pneumonia criteria. Patients with high P. aeruginosa burden seemed to possess more virulent strains.
Zhuo
Hanjing
H
Cardiovascular Research Institute, University of California San Francisco, CA, USA.
Yang
Katherine
K
Lynch
Susan V
SV
Dotson
Rachel H
RH
Glidden
David V
DV
Singh
Gaurav
G
Webb
W Richard
WR
Elicker
Brett M
BM
Garcia
Oscar
O
Brown
Ronald
R
Sawa
Yoriko
Y
Misset
Benoît
B
Wiener-Kronish
Jeanine P
JP
D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D015169:Colony Count, Microbial; D003937:Diagnosis, Differential; D005260:Female; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000175:diagnosis* / Q000188:drug therapy / Q000401:mortality*; D011446:Prospective Studies; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification*; D012121:Respiration, Artificial; D012307:Risk Factors; D013997:Time Factors; D014132:Trachea / Q000382:microbiology*; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents