Clostridioides difficile is a Gram-positive anaerobic bacterium that primarily causes severe intestinal infections associated with antibiotic use, particularly pseudomembranous colitis. It spreads through contaminated environments or surfaces. Symptoms include diarrhea, abdominal pain, and fever, and in severe cases, it can lead to dehydration, bowel perforation, or even death. C. difficile infections are common in patients who are hospitalized long-term or receiving broad-spectrum antibiotics.