Acinetobacter baumannii. Scanning Electron micrograph (SEM) of Acinetobacter baumannii. This aerobic Gram-negative, non-motile bacteria are normal flora on the skin. But because A. baumannii has developed substantial antimicrobial resistance, it is an emerging cause of nosocomial infections in hospitals, responsible for pneumoniae, hemopathic and wound infections. Magnification of 12739x.