It's called C. difficile and the CDC says it is causing infection rates to hit historic highs.
The Centers for Disease Control says the dangerous bacteria spreads not only in hospitals but also in other health care settings. They say it is a deadly diarrheal infection that poses a significant threat to US health care patients and is causing many Americans to suffer and die.
People most at risk are those who take antibiotics and also receive care in any medical facility.
The CDC says much of the growth of this epidemic has been due to the overuse of antibiotics.