The bacterium that thrives when your body's helpful microbial defenses are wiped out.

Gardening · Published 3 October 2026 Swipe more like this →

In short: Clostridioides difficile, once known as Clostridium difficile, is a bacterium that colonizes the human gut. While often harmless, it can trigger severe, life-threatening infections when antibiotics disrupt the natural balance of your intestinal flora, allowing this resilient pathogen to proliferate and release toxins that damage the colon lining.

The bacterium, commonly called C. diff, is an opportunistic pathogen that typically enters the body through the mouth. While it can exist in a dormant state in soil, water, and on various surfaces, it becomes active upon reaching the colon. In a healthy gut, a diverse range of bacteria keeps C. diff in check. However, when a person takes antibiotics, these medications often destroy the protective, beneficial bacteria alongside the target infection, creating an environment where C. diff can multiply rapidly.

Symptoms of an infection range from mild, watery diarrhea to severe complications such as toxic megacolon, where the colon becomes inflamed and dangerously enlarged. In extreme cases, the infection can lead to sepsis, kidney failure, or bowel perforation, which may be fatal if not treated promptly. Risk factors include advanced age, prolonged hospital stays, and the use of proton pump inhibitors, which reduce stomach acid and may alter the gut environment in ways that favor the bacteria.

Treatment often involves stopping the initial antibiotic and starting a specific 10-day course of a different antibiotic to clear the infection. Because C. diff is highly resilient and can spread easily via contaminated surfaces or unwashed hands, standard hand sanitizers are ineffective; thorough handwashing with soap and water is essential for prevention. For patients with recurrent infections, a faecal microbiota transplant—introducing bacteria from a healthy donor into the patient's gut—is sometimes used to restore the necessary microbial balance.

It is important to note that the taxonomy of these organisms has evolved. While the pathogen was historically classified within the genus Clostridium, it was reclassified as Clostridioides difficile in 2016. This distinction is significant because the broader Clostridium genus includes a diverse array of anaerobic bacteria, some of which are beneficial or industrially useful, while others produce potent toxins like the one responsible for botulism.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

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