Clostridium difficile is a leading cause of nosocomial diarrhoea. The production of two toxins A (enterotoxin) and B (cytotoxin) causes the characteristic mucosal damage consisting of plaque-like lesions leading to the formation of a pseudomembrane. Not all strains of C. difficile produce toxin and therefore not all can cause illness. The spectrum of disease ranges from a self-limiting mild diarrhoea to the advanced and severe illness characteristic of pseudomembranous colitis. The most accurate diagnosis of pseudomembranous colitis is affected by endoscopic detection of colonic pseudomembranes or microabscesses in antibiotic-treated patients who are suffering from diarrhoea and who have C. difficile and its toxins in their stools.
Clostridium difficile testing algorithm:
A GDH screening test is initially performed on a stool sample requesting C. difficile. If this is negative, C. difficile infection is highly unlikely and no further testing is required. If the GDH screen is positive, C. difficile toxin testing is performed. If this toxin test is positive, C. difficile infection is highly probable and the sample is reported as positive. If the C. difficile toxin testing is negative, we recommend testing samples for confirmatory PCR testing. Clinicians will be contacted before a sample is referred for PCR testing.
