Acinetobacter baumannii is a species of pathogenic bacteria, referred to as an aerobic gram-negative bacterium, which is resistant to most antibiotics. As a result of its resistance to drug treatment, some estimates state the disease is killing tens of thousands of U.S. hospital patients each year and specialists say they could emerge as a bigger threat. They are typically short, almost round, and rod shaped. The illness can cause severe pneumonia and infections of the urinary tract, bloodstream and other parts of the body.