Imipenem resistance among Pseudomonas aeruginosa isolates: risk factors and impact of resistance on clinical outcomes in a Tunisian burn unit

Abstract number: R2440

Thabet L., Bousselmi K., Messadi A.

Pseudomonas aeruginosa is an important cause of nosocomial infections particularly in burned patients. Imipenem is one of the most effective drugs against P. aeruginosa, but imipenem resistance had occurred and has increasingly been reported in P. aeruginosa.

This study was conducted to determine the risk factors for acquisition of imipenem resistant P. aeruginosa(IRPA)and the impact of this resistance on clinical outcomes at a Tunisian burn unit.

Patients hospitalised in the burn unit from January 2005 to December 2006 were included in this study. The features of patients with IRPA isolates were compared with those of patients with imipenem susceptible P. aeruginosa isolates (ISPA). Demographic features, total burn surface area (TBSA), burn depth, antimicrobial used 15 days before, presence of IRPA in the unit at the same period and previous ISPA isolated from the patient were included in the risk factors analysis. We compared length of hospitalisation and mortality in the two groups of ISPA and IRPA.

P. aeruginosa was recovered from 64 patients in this period, 25 were IRPA and 39 were ISPA.

There was no significant difference between patients with ISPA and patients with IRPA in terms of age, TBSA burn depth and length of hospitalisation. The percentages of septic choc were 64% in IRPA group compared with 47% in ISPA group. The mortality rate among patients infected with IRPA was significantly higher: 40% versus to 17.9% with ISPA (relative risk= 2. 23, p = 0.05).

Previous ISPA isolate from the patient (OD=14. 8, p = 0.02) and hospital admission in the previous year (OD=8.25, p = 0.002) were independent risk factors for acquisition of IRPA.

However, the presence of IRPA in the unit at the same period and antibiotic use before isolation were not significantly associated with IRPA in our study (P > 0.05).

The imipenem resistance among P. aeruginosa strains had a significant impact on mortality in our study. The presence of ISPA in a patient before isolation of IRPA is a significant risk for acquisition of IRPA; P. aeruginosa has the ability to develop drug resistance during therapy. Carapenem exposure led the microorganism to this resistance. Therefore, the judicious use of these antibiotics might be an important strategy to prevent the imipenem resistance.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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