医療微生物学と診断

Ventilator-Associated Pneumonia Caused by Pseudomonasaeruginosa in Intensive Care Unit: Epidemiology and Risk Factors

Abstract

Enrico Raineri, Laura Porcella, Annamaria Acquarolo, Luciano Crema, Fulvio Albertario and Andrea Candiani

Purpose: We studied the risk factors for the acquisition of Ventilator-associated Pneumonia (VAP) caused by Pseudomonas aeruginosa in two Intensive Care Units (ICU).

Methods: We carried out a case-control study, from January 1, 2006 through June 30, 2008. We defined as CASES patients with Pseudomonas aeruginosa VAP and CONTROLS patients with VAP caused by other Gramnegative bacteria.

Results: The study of risk factors for the development of VAP by Pseudomonas aeruginosa showed that three of them are referred to the pre-ICU admission history of the patient: hospitalization during previous 6 months, admission from other wards/hospitals instead of domicile provenance (p<0.01) and duration of pre-ICU hospitalisation (p<0.01, at multivariate analysis: OR 2.09 IC95% 1.18-3.72). Analysis of antibiotic prescription before the development of VAP showed as independent risk factor the number of different antibiotic classes prescribed to patients or rather the complexity of antibiotic exposure (OR 2.3 IC95% 1.14-4.67). Analysis of mortality revealed a non-significant difference between VAP caused by Pseudomonas or other Gram-negative bacteria, although our data suggest an association between MDR Pseudomonas infection and higher mortality (p=0.03).

Conclusion: Our study offers points that can contribute to improve the empiric antibiotic prescription in ICU. In presence of in-hospital patients presenting with a previous history of antibiotic prescription, with a complex clinical condition preceding ICU admission or with a prolonged ventilatory assistance, presenting with signs or symptoms of infection, should be advisable to prescribe a therapy with a specific activity against Pseudomonas aeruginosa.