A report has been published on the investigation into an outbreak of E. coli O157 infection that affected at least 19 people in the UK in August and September this year. Seven of those affected by the outbreak required hospital treatment.
The outbreak was linked to consumption of watercress purchased from supermarket chain Sainsbury’s and the investigation report confirms that bagged washed watercress from the retailer was the likely vehicle of infection. It is thought that this was the first reported outbreak of Shiga toxin-producing E. coli to be associated with watercress.
Although the outbreak is considered to be over, the investigation is on going at the 10 farms known to have supplied watercress for Sainsbury’s. To date the original source of the contamination has not been confirmed, although agricultural run-off, water contamination and contaminated seeds are all possibilities. There have been no related cases outside the UK reported, but the authors of the investigation report warn that international trade in watercress seeds could be a source of cases elsewhere if they are contaminated.
The report is published in the online journal Eurosurveillance and can be found in full here.