Clostridioides difficile was previously named Clostridium difficile. It is often called C. diff. It is a toxin-producing bacterium. It forms spores that can live a long time outside the body. The spores are not killed by stomach acid and can infect the intestines.
The bacteria are common. They typically do not make healthy people sick. Infections usually follow antibiotic use. Older adults in hospitals or long-term care facilities are most vulnerable. Watery diarrhea, ranging from mild to severe, is the most common symptom. In rare cases, C. diff infections can be fatal.