Learn how one species of bacteria, which is harmless to most people, has evolved to become deadly to others in this video from NOVA scienceNOW. 

The bacterium, known as Acinetobacter baumannii in medical science, and as "Iraqibacter" to soldiers both in and returning from Iraq, has developed resistance to even the strongest of antibiotics. Iraqibacter's genome reveals that much of its resistance has been acquired from other bacteria species through a process known as horizontal gene transfer. The video also examines how scientists may be able to prevent the bacteria from infecting humans.