Clostridium difficile is a spore-forming bacterium that can cause antibiotic-associated diarrhea and colitis. It is transmitted through the fecal-oral route via contaminated surfaces or hands. Antibiotic use disrupts normal gut flora and allows C. difficile to cause infection. Symptoms range from mild diarrhea to life-threatening complications. Treatment involves discontinuing antibiotics if possible and using metronidazole or vancomycin for severe cases. Preventing transmission requires contact precautions, thorough hand hygiene and environmental disinfection.