Assessment of the risk factors for mortality in hospital-acquired Acinetobacter baumannii infections in a teaching hospital

Abstract number: 1733_1432

Bulut C., Yetkin M.A., Erdinc F.S., Ataman Hatipoglu C., Onde U., Karakoc E.A., Tülek N.

Objectives:Acinetobacters are increasingly involved as aetiological agents of hospital acquired infections in seriously ill patients, in recent years. The aim of this study was to evaluate the hospital acquired Acinetobacter baumannii infections and to assess the risk factors associated with mortality.

Methods: Prospective laboratory based active surveillance has been performed in our hospital between January 2000 and December 2004. Hospital acquired infections were diagnosed according to the CDC criterias. Conventional methods were used for the identification of Acinetobacter isolates. Disc diffusion method was used for antimicrobial susceptibility test of the microorganisms.

Results: Hospital acquired Acinetobacter baumannii infections were detected in 95 male and 71 woman patients. The mean age of the patients were 58.0±17.8 years. Acinetobacter baumannii was isolated mainly from the ICU patients (32.5%), from the patients on the orthopaedy wards (16.3%) and on the neurology ward (11.4%) consecutively. Predisposing factors detected in the patients infected with Acinetobacter baumannii were urinary catheter insertion (81.3%), mechanical ventilation (25.3%) and central venous catheter (21.1%) consecutively. The mean duration of time between hospitalisation and occurrence of infection were 17.2±14.8 days. Urinary tract infection, surgical site infection, primary bloodstream infection and hospital acquired meningitis were the most common infections and existed in 30.1%, 29.5%, 17.5% and 7.3% of patients respectively. Carbapenems and netilmicin were the most effective antimicrobials agents against Acinetobacter isolates and an evident decrease in amicasin resistance was detected overall the five year period.

Crude mortality rate was 36.5%. Older age (≥60 years), mechanical ventilation, presence of central venous catheter, tracheostomy, being an ICU patient, presence of coma and having a carbapenem resistance were found to be associated with mortality due to A baumannii infection by univariate analysis. Of these factors older age (≥ 60 years), mechanical ventilation, presence of coma and being an ICU patient were independently associated with mortality on multivariate analysis (p < 0.05).

Conclusion: These data suggest that, clinical efforts aimed at the improvements in the medical management of ICU patients with severe A. baumannii infection especially those who need mechanical ventilation, are required for further improvement in patient outcome.