Clostridium difficile Diseases

Clostridium difficile is an anaerobic spore-forming, gram-positive bacillus. C. difficile may be present as part of the normal intestinal flora in approximately 50 percent of healthy neonatal children and less than four percent of adults. Under normal circumstances, C. difficile does not cause clinical disease. Following treatment with many antibiotics and suppression of the normal intestinal flora, C. difficile becomes an opportunistic pathogen producing enteritis and diarrhea.

Those patients that are at risk for C. difficile associated disease include patients receiving chemotherapy for cancer, and patients having received antibiotic therapy. Most antibiotics can initiate C. difficile associated disease, but the disease is most frequently associated with treatment with ampicillin, clindamycin and cephalosporins. The late stage enteritis, inflammation of the intestine, is called pseudomembranous colitis. Diarrhea associated with C. difficile is called antibiotic associated diarrhea. Collectively, the two diseases are called C. difficile associated disease. In addition to the antibiotic induced C. difficile associated disease, C. difficile associated disease is most frequently associated with nosocomial infections in hospitals and nursing homes.

Diagnosis of Clostridium difficile Diseases

Traditionally, laboratory diagnosis of C. difficile associated disease is dependent on one or two criteria. The first is detection and identification of the infective organism by culture or antigen detection tests using latex agglutination or immunoassay procedures. Second, a tissue culture cytotoxicity test is used to detect the presence of the cytotoxin, toxin B. C. difficile produces two toxins, toxin A and toxin B. Toxin A is the extracellular enterotoxin that is responsible for the in vivo effects of the bacterium and also exhibits cytotoxic effects in vitro. Toxin B is the extracellular cytotoxin that is responsible for the in vitro cytotoxic effects of the organism. Most immunoassays measure toxin A because it is primarily responsible for the pathology of the bacterium.

The Triage® Clostridium difficile Panel is an enzyme immunoassay for the simultaneous detection of an antigen produced by C. difficile (C. difficile common antigen or glutamate dehydrogenase) and toxin A. The Triage Clostridium difficile Panel detects glutamate dehydrogenase with an analytical sensitivity of 2 ng/mL and toxin A with an analytical sensitivity of 2 ng/mL.