RESUMO
Background: Over the last decade, Acinetobacter baumannii has been an important cause of nosocomial infections worldwide.Aim: To assess clinical and epidemiological characteristics of patients during a large citywide outbreak of carbapenem-resistant A. baumannii (CRAB). Methods: Retrospective cross-sectional study that evaluated the information obtained from the official notification system for CRAB within the Municipal Health Department, Porto Alegre, Brazil, in the period of July 1st, 2007 to December 31st,2008.Results: A total of 1,260 CRAB from infection (608 [48.3%]) or colonization (652[51.7%]) were reported in 18 hospitals. Most patients (53.5%) were hospitalized at intensive care units and have been exposed to invasive procedures, but 757 (60.7%)patients had no underlying comorbidity reported. A total of 1,143 (90.7%) patients received some antimicrobial 90 days before CRAB detection and 36.4% received a carbapenem. Data on the outcome were available for 618 (49.0%) patients and 54.3% of them died. Infection was significantly more common in patients admitted to public hospitals; with trauma, with exposure to antibiotics in the previous 90 days, and in patients submitted to invasive procedures. Conclusion: This study suggests that in the context of an outbreak, baseline comorbidities and previous carbapenem exposure may be less important risk factors for CRAB infection/colonization.