Clostridium difficile infection: pathophysiology and diagnosis.

Clostridium difficile is a relatively common enteric pathogen encountered most frequently in association with antibiotic use and as a nosocomial pathogen. Four factors dictate clinical expression: (1) acquisition of the organism from environmental sources or previous colonization; (2) distortion of the competing colonic flora by antibiotics; (3) toxin production; and (4) age-related susceptibility. Characteristics of clinical features include inflammatory diarrhea (cramps, fecal leukocytes, systemic response), endoscopic evidence of colitis or pseudomembranous colitis, and protein-losing enteropathy. The usual diagnostic tests are designed to detect toxin B with a tissue culture assay or toxin A with an enzyme immunoassay.