Acinetobacter baumannii has emerged as a significant nosocomial pathogen in hospitalized patients worldwide. A. baumannii, the most frequently isolated species and the most clinically important in the last 20 years, has been implicated in a variety of infections, such as bacteremia, urinary tract infections and meningitis, but its predominant role is as a causative agent of pneumonia, particularly in intensive care unit (ICU) patients. Ventilator-associated pneumonia (VAP) caused by Acinetobacter spp. has a high attributable mortality. Approximately 65% of the studies published on "nosocomial infections caused by Acinetobacter" are located from the year 2000 onwards.(1, 2, 3) The therapeutic difficulties due to the wide resistance of this bacterium to most antibiotics, together with its great capacity to survive for a long time in the hospital environment, increase the opportunities for it to be transmitted between patients, either through the human reservoir or through contaminated inanimate materials.