Is Re-Emerging Superbug the Next MRSA?

"What was surprising was not just the rates, but the number of severe cases," said Johnson, who helped treat Joan Corboy's illness.

Similar to MRSA, C. diff is an infection that is mainly acquired in a hospital or nursing home, although like MRSA there is some evidence that a community-acquired strain may be developing, according to the CDC.

"When a patient is in the hospital getting antibiotics for some type of infection, one of the potential complications is that the normal bacterium that lives in the colon is disturbed with that antibiotic. That makes you susceptible to an infection with Clostrium difficile," Johnson said. "The great majority of cases occur in people who have recently used antibiotics."

When C. diff is not actively dividing, it forms very tough spores that can exist on surfaces for months and years, making it very difficult to kill, Johnson said.

"Antibiotics are very effective against the growing form of the bacteria but it doesn't do anything to the spores," Johnson said. "If there are spores they can sit around like stealth bombs. Once the antibiotic is gone, these spores can germinate again and spread their toxins."