Risk factors for nosocomial imipenem-resistant Acinetobacter baumannii infections

Abstract number: p916

Baran  G., Erbay  A., Bodur  H., Onguru  P., Akinci  E., Balaban  N., Cevik  M.A.


To identify the risk factors for nosocomial imipenem-resistant A. baumannii (IRAB) infections.


The study was conducted prospectively between January to December 2004 at a tertiary care hospital in Ankara. The patients who had nosocomial A. baumannii infections were enrolled to the study. The characteristics of the patients who had IRAB infections and imipenem-sensitive A. baumannii (ISAB) infections were compared. Only the first isolation of A. baumannii was considered. Nosocomial infections were defined according to CDC criteria.


IRAB was isolated from 66 (53.6%) patients, and ISAB was isolated from 57 (46.3%) patients during the study period. IRAB were most frequently isolated from tracheal aspirate (28.7%) and blood (21.2%) cultures whereas, ISAB were most frequently isolated from wound (33.3%) and blood (31.5%) cultures. Mean duration of hospital stay until A. baumannii isolation was 20.8 ± 13.6 days in IRAB infections whereas 15.4 ± 9.4 days in ISAB infections. 65.1% of the patients with IRAB infection and 40.3% of patients with ISAB infection were followed at intensive care unit (ICU). Previous carbapenem use was present in 43.9% of the patients with IRAB and 12.2% of the patients with ISAB infection. According to the univariate analysis female sex, ICU stay, emergent surgical operation, total parenteral nutrition, having central venous catheter, endotracheal tube, urinary catheter, previous antibiotic use and previous administration of carbapenems were significant risk factors for IRAB infections (p < 0.05). In multivariate analysis, longer duration of hospital stay until A. baumannii isolation [odds ratio (OR), 1.043; 95% confidence interval (CI), 1.003 -1.084, p = 0.032], previous antibiotic use (OR, 5.051; 95% CI, 1.004-25.396, p = 0.049) and ICU stay (OR, 3.1; 95% CI, 1.398-6.873, p = 0.005) were independently associated with imipenem resistance.


Our results suggest that the nosocomial occurrence of IRAB is strongly related to an ICU stay, duration of hospital stay and IRAB occurrence may be favoured by the selection pressure of previously used antibiotics.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Location: Oxford, UK
Presentation type:
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