Patterns of colonization by Pseudomonas aeruginosa in intubated patients: a 3-year prospective study of 1,607 isolates using pulsed-field gel electrophoresis with implications for prevention of ventilator-associated pneumonia.
OBJECTIVE
To identify routes and patterns of colonization with Pseudomonas aeruginosa in intubated patients to design strategies of prevention for respiratory infection.


METHODS
Prospective and observational study in the 16-bed intensive care unit of a teaching hospital.


METHODS
Ninety-eight intubated patients were investigated over a 3-year period. Those ventilated less than 72 h were excluded.


RESULTS
Samples from the tap water from each patient's room, stomach, oropharynx, subglottic secretions, trachea, and rectum were collected when the patient was intubated, and then three times per week. Pulsed-field gel electrophoresis was performed to type the strains. We identified 1,607 isolates pertaining to 35 different pulsotypes. Overall 54.2% of patients presented colonization, and tracheal colonization was present in 30.5%. Ten patients had colonization at intubation, and four of these developed ventilator-associated pneumonia (VAP) after a mean of 4+/-2 days. ICU-acquired colonization occurred in 31 patients, and 4 of these developed VAP after a median of 10+/-5 days. P. aeruginosa was isolated from the room's tap water in 62.4% of samples. More than 90% of tap water samples had pulsotypes 1 and 2, which were frequently isolated in the stomach (59%) but were only rarely associated with VAP.


CONCLUSIONS
Although colonization/infection with P. aeruginosa in intubated patients tends to be endogenous, exogenous sources should not be ruled out. A combination of early identification (and eradication) of airways colonization by P. aeruginosa plus infection control measures targeted to reduce cross-contamination should be the basis to prevent pulmonary infection.
Vallés
Jordi
J
Critical Care Center, Hospital Sabadell and UDIAT Diagnostic Center, Institut Universitari, Universitat Autónoma Barcelona, Parc Tauli s/n, 08208 Sabadell, Spain. jvalles@cspt.es
Mariscal
Dolors
D
Cortés
Pilar
P
Coll
Pere
P
Villagrá
Ana
A
Díaz
Emili
E
Artigas
Antonio
A
Rello
Jordi
J
D000368:Aged; D003428:Cross Infection / Q000382:microbiology / Q000517:prevention & control; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D006761:Hospitals; D006801:Humans; D007362:Intensive Care Units; D007440:Intubation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000175:diagnosis / Q000209:etiology* / Q000382:microbiology; D011446:Prospective Studies; D011552:Pseudomonas Infections / Q000175:diagnosis / Q000209:etiology* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification*; D012121:Respiration, Artificial / Q000009:adverse effects