Imipenem-resistant Pseudomonas aeruginosa infection at a medical-surgical intensive care unit: risk factors and mortality.
OBJECTIVE
The aim of this study was to evaluate the risk factors and attributable mortality associated with imipenem-resistant Pseudomonas aeruginosa (IRPA) infections in a medical-surgical intensive care unit (ICU).


METHODS
A retrospective case-control study was carried out at a 16-bed medical-surgical ICU in a 780-bed, university-affiliated hospital. All patients admitted from January 1, 2003, to December 31, 2004, who had nosocomial infection caused by IRPA, were included in the study.


RESULTS
Imipenem-resistant P. aeruginosa was recovered from 63 patients during the study period. One hundred eighty-two controls were matched with cases by period of admission, age, and time at risk. Urinary tract (34.9%) and respiratory tract (22.2%) were the main sources of IRPA isolation. In multivariate analysis, a previous stay in the ICU (odds ratio, 3.54; 95% confidence interval [CI], 1.29-9.73; P = .03) was the only independent risk factor for IRPA infection. The in-hospital mortality rate among case patients was 49% (31 of 63) compared with 33% (61 of 182) for control patients (odds ratio, 1.92; 95% CI, 1.07-3.44; P = .02). Thus, we had an attributable mortality of 16% (95% CI, 9.74%-22.3%; P = .03).


CONCLUSIONS
Our study suggests that IRPA infections are strongly related to previous ICU stay, and that IRPA infections significantly increase mortality in those critical patients.
Furtado
Guilherme H C
GH
Hospital Epidemiology Committee, Division of Infectious Diseases, Federal University of São Paulo, São Paulo, Brazil. ghfurtado@uol.com.br
Bergamasco
Maria D
MD
Menezes
Fernando G
FG
Marques
Daniel
D
Silva
Adriana
A
Perdiz
Luciana B
LB
Wey
Sérgio B
SB
Medeiros
Eduardo A S
EA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000890:Anti-Infective Agents / Q000494:pharmacology*; D016022:Case-Control Studies; D024881:Drug Resistance, Bacterial; D005260:Female; D017052:Hospital Mortality; D006785:Hospitals, University; D006801:Humans; D015378:Imipenem / Q000494:pharmacology*; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011552:Pseudomonas Infections / Q000382:microbiology / Q000401:mortality*; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult
D000890:Anti-Infective Agents; D015378:Imipenem