Spectrum of antibiotic-associated diarrhoea.

In an attempt to find the extent to which Clostridium difficile could be implicated as the cause of antibiotic-associated diarrhoea, the stools of 53 patients who had diarrhoea after a course of antibiotics were investigated for the presence of C. difficile toxin. Ten of the patients (19%) were found to be positive, but the stools of four out of 53 patients without diarrhoea after a course of antibiotics were also found to contain C. difficile toxin (7.5%). The titre of toxin in patients both with and without diarrhoea fell within the same range (up to 10(-5)). Neither the organism nor its toxin was found in the stool of 26 patients with ulcerative colitis, eight with Crohn's disease, 49 with non-specific diarrhoea, and 27 normal controls. We conclude that, while C. difficile is responsible for a proportion of cases of antibiotic-associated diarrhoea, the concentration of toxin is not the sole factor affecting the severity of this disorder.