Acinetobacter baumannii is a strict aerobic gran negative coccobacillus, able to acquire multiple resistance to broad-spectrum antibiotics due to its ability to take fragments of genetic material from other bacteria, for further incorporation of this material into its own chromosome. Acinetobacter baumannii is the cause of several nosocomial infections and of numerous outbreaks in hospitals over different continents. This paper includes a literature review of scientific articles published since January 2010 about this microorganism, its environment, mechanisms of resistance and virulence, as well as commonly used treatment.