Definition of Clostridium difficile

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Clostridium difficile: A bacterium that is one of the most common causes of infection of the large bowel (colon). In technical terms, Clostridium difficile (C. difficile) is an obligate anaerobic or microaerophilic, gram-positive, spore-forming, rod-shaped bacillus.

C. difficile is now recognized as the chief cause of nosocomial (hospital-acquired) diarrhea in the US and Europe. Recognition of this disease began in the 1970s with reports of a serious, sometimes lethal, colitis characterized by the formation of pseudomembranous plaques. The cause was identified as C. difficile in 1978. The organism is now endemic (continuously present) not only in hospitals but also in nursing homes and other facilities for long term care.

Patients taking antibiotics are at risk of becoming infected with C. difficile. Antibiotics disrupt the normal bacteria of the bowel, allowing C. difficile bacteria to become established in the colon. The chief risk factor for the disease is prior exposure to antibiotics. A prolonged course of antibiotics or the use of two or more antibiotics in combination increases the risk of C. difficile diarrhea. The cephalosporin antibiotics are the leading instigators of C. difficile diarrhea. Other culprits include clindamycin, ampicillin, and amoxicillin.

Many persons infected with C. difficile bacteria have no symptoms. These people become carriers of the bacteria and can infect others. In other people, a toxin produced by C. difficile causes diarrhea, abdominal pain, severe inflammation of the colon (colitis), fever, an elevated white blood count, vomiting and dehydration. In severely affected patients, the inner lining of the colon becomes severely inflamed (a condition called pseudomembranous colitis). The walls of the colon can wear away and holes can perforate the colon, leading to a life-threatening infection of the abdomen.

In 2003 and 2004, C. difficile spread through hospitals in Quebec and Alberta and contributed to the deaths of 100 patients, mainly older patients, in one institution alone. The rate of patients contracting C. difficile increased from 2.1 cases per 1,000 admissions in 2002 to 10 per 1,000 in 2003 and the upward trend continued in 2004.

The treatment of C. difficile diarrhea includes rehydration and administration of an antibiotic to which the bacteria are sensitive. Passive immunotherapy using pooled normal human immune globulin (which contains IgG antibody against toxin A) is effective in treating recurrent or refractory C. difficile diarrhea. This reflects the fact that an inadequate immune response to C. difficile predisposes patients to severe, prolonged, and recurrent C. difficile diarrhea.