Perhaps you've heard about Clostridium difficile or C. difficile, or C. diff. It's been spreading more and more every year through hospitals and other health care facilities to the point where in some regions, like the southeast U.S., it is even more aggressive than the more well-known superbug, methicillin-resistant Staphylococcus aureus (MRSA) bug. But others can get it, even if they are generally healthy and not in a hospital setting.