Culture negative cytotoxin positive stools in community acquired diarrhoea.

In a significant proportion of cases of community acquired diarrhoea no recognised pathogen is detected. Verocytotoxin producing Escherichia coli (VTEC) are associated with haemorrhagic colitis and the haemolytic uraemic syndrome but their role in community acquired diarrhoea is not fully understood. Using a method of toxin enhancement in mixed faecal culture, 175 stools negative on culture for recognised pathogens were tested for the presence of cytotoxin and 28% were found to be positive. Nine were neutralised by anti-VT1, 29 by anti-VT2, and eight by neither. No control stool samples yielded any cytotoxin. VTEC should be considered as a causative agent in sporadic community acquired diarrhoea.