Clostridium difficile, also known as C. Difficle or c. diff, is a bacterium which causes the uncomfortable and often deadly gastrointestinal disease, Clostridium difficile colitis or pseudomembranous colitis. Symptoms include: watery diarrhea, up to 15 times each day; severe abdominal pain; loss of appetite; fever; blood or pus in the stool; and weight loss.  C. diff is linked to the death of 14,000 Americans per year.
Once an outbreak occurs, it can be spread easily in hospitals and other institutions by fecal–oral route. Patients must be placed on contact isolation. Proper hand washing with soap and water and wearing gloves is imperative to stop the spread. Alcohol-based hand rubs are ineffective against c. diff.
Many acquire it when the normal microbiome is decimated with antibiotics, surgery, certain drugs and diseases. C. diff infections are not common in healthy populations. Vulnerable populations who are at risk include those who have had: a course of long-term antibiotics; surgery of the gastrointestinal (GI) tract; diseases of the colon such as inflammatory bowel disease or colorectal cancer; a weakened immune system; use of chemotherapy drugs; previous C. diff infection; advanced age -- 65 or older; kidney disease; or use of drugs called proton-pump inhibitors, which lessen stomach acid.
Milder cases can be eliminated by stopping the antibiotics or drugs that triggered the GI distress and taking probiotics. This bacteria has become antibiotic resistant to most antibiotics, though Flagyl, Dificid, and Vancocin still work against some c. diff infections. If the normal gut flora is not restored, then there is a high rank of recurrence.
Fecal matter transplant treatment
A newer and more highly effective treatment is a fecal matter transplant, where the fecal matter from a person with healthy gut flora is mixed with saline, strained, inserted into the patient with Clostridium difficile colitis via a colonoscopy, endoscopy, sigmoidoscopy, or enema in order to recolonize the ill person's bowels.
C. difficile and ME/CFS
Dr. Jacob Teitelbaum stated that: "22 percent of our CFS/fibromyalgia patients had an infection with a toxin producing bacteria called Clostridium Difficile. This contrasts to only one percent of a healthy population! The toxin produced by these bacteria can severely affect the bowel as well. Our experience also suggests that these infections can result in incompletely digested food being absorbed into the bloodstream (the so-called "leaky gut syndrome")."
- Bakken, Johan S.; Borody, Thomas; Brandt, Lawrence J. (December 2011), "Treating Clostridium difficile Infection With Fecal Microbiota Transplantation", Clinical Gastroenterology and Hepatology, 9 (12): 1044 - 1049, PMID 21871249, doi:10.1016/j.cgh.2011.08.014