Nosocomial infections due to Acinetobacter species: Clinical findings, risk and prognostic factors

Abstract

Nosocomial infections caused by Acinetobacter species is of increasing concern in critically ill patients, and the risk factors for this infection are not well established. The present investigation was done to determine incidence of nosocomial Acinetobacter infections. Our study retrospectively attempts to find risk and prognostic factors for the nosocomial acquisition of Acinetobacter infection. The medical records of 43 patients with Acinetobacter infection during two-year period (Oct1998-Oct2000) were reviewed to find the factors involved in the nosocomial acquisition of Acinetobacter. Acinetobacter isolates that were obtained from these patients were phenotypically typed using carbon assimilation tests. Antimicrobial susceptibility testing results were noted from the microbiology records. Acinetobacter baumannii accounted for 41.8% (n=18) of all the infections. By multivariate logistic regression analysis, only resistant antibiotype {(Ceftazidime- OR, 7.13 [95% CI, 1 to 46];p= 0.044); (Cefotaxime- OR, 6.09 [CI, 0.87 to 30];p = 0.045)} and mechanical ventilation (OR, 5.84 [CI, 0.83 to 31];p = 0.05) were found to be potential independent risk factors for mortality. Overall mortality rate was 33%. Most of A. baumannii isolates were multidrug resistant in our set up and infections due to them were associated with high mortality. Prevention of Multiple drug resistant (MDR) A. baumannii infections was achieved after discontinuation of cefotaxime in ICU. Infection with resistant clones and mechanical ventilation were found to be potential independent risk factors for mortality.