Nosocomial multi-drug resistant Acinetobacter baumannii bloodstream infection:: risk factors and outcome with ampicillin-sulbactam treatment

The emergence of multidrug-resistant (MDR) Acinetobacter baumannii poses a therapeutic problem. The aim of this study was to assess the risk factors for nosocomial. MDR-A. baumannii bloodstream infection (BSI) and the efficacy of ampicillin-sulbactam (A/S) in its treatment. Of 94 nosocomial A. baumannii BSI during the year 2000, 54% involved MDR strains, 81% of which were genetically related. Various risk factors for MDR-A. baumannii were found, of which intensive-care unit admission and prior aminoglycoside therapy were independently associated with MDR-A. baumannii acquisition on multivariate analysis. Of MDR-A. baumannii BSI cases, 65% received A/S and 35% inadequate antibiotic therapy, whereas of 43 non-MDR cases, 86% were treated according to susceptibility and 14% inappropriately with antibiotics to which these organisms were resistant. Crude mortality was comparable in the adequately treated groups. Respective mortalities among patients treated adequately and inadequately were 41.4 and 91.7% (p < 0.001). Among severely ill patients, A/S therapy significantly decreased the risk of death (P = 0.02 OR = 7.64). MDR-A. baumannii has become highly endemic in our institution. A/S appears to be one of the last effective and safe empirical resorts for treatment of MDR A. baumannii BSI. (C) 2003 The Hospital Infection Society. Published by Elsevier Science Ltd. All rights reserved.