Clostridioides (Clostridium) difficile is a Gram-positive, obligately anaerobic bacterium that forms resistant spores and produces toxins that cause diarrhea and colitis in humans and other animals.
Explanation
C. difficile is part of the normal intestinal microbiota in a small proportion of healthy adults and many infants. The bacterium exists in two forms: a vegetative cell that is sensitive to oxygen and produces toxins, and a dormant spore that can survive in the environment for months. When antibiotics or other factors disrupt the normal gut flora, C. difficile spores germinate and the vegetative cells proliferate. They produce two major toxins that damage the intestinal epithelium, leading to inflammation, fluid loss and formation of characteristic pseudomembranes. Clinical symptoms range from mild watery diarrhea to severe colitis, toxic megacolon and sepsis. Hospital settings provide conditions for transmission because spores contaminate surfaces and are resistant to many disinfectants. Risk factors include recent antibiotic therapy, advanced age and underlying illness.
Clinical aspects
Diagnosis is based on detecting toxins in stool samples or identifying toxin genes by molecular assays. Treatment often involves discontinuing the inciting antibiotic and administering oral vancomycin or fidaxomicin. In severe or recurrent cases, fecal microbiota transplantation restores normal gut flora and reduces relapse. Preventing C. difficile infection depends on prudent antibiotic use, thorough hand hygiene with soap and water, environmental decontamination and isolation of symptomatic patients. As understanding of this organism has improved, the name of the genus was changed to Clostridioides to reflect its genetic distinctness from other clostridia. This toxigenic bacterium illustrates how disruption of microbial communities can allow opportunistic pathogens to flourish, emphasizing the importance of microbiota balance and infection control measures. Related Terms: pseudomembranous colitis, antibiotic-associated diarrhea, spore, toxin, anaerobe