Acinetobacter baumannii may be a typically short, almost round, rod-shaped (coccobacillus) Gram-negative bacterium. it's named after the bacteriologist Paul Baumann.It are often an opportunistic pathogen in humans, affecting people with compromised immune systems, and is becoming increasingly important as a hospital-derived (nosocomial) infection. While other species of the genus Acinetobacter are often found in soil samples (leading to the common misconception that A. baumannii may be a soil organism, too), it's almost exclusively isolated from hospital environments.Although occasionally it's been found in environmental soil and water samples,its natural habitat remains not known.