The UK's largest ever STEC 0145 E. coli outbreak was likely caused by contaminated Apollo leaf lettuce in pre-packed sandwiches, according to a recent report. Despite extensive investigations, authorities remain unable to confirm the exact source of contamination. Between May and November last year, 293 people were affected by the bacteria, which can cause severe food poisoning with symptoms including diarrhoea, stomach cramps, vomiting, and fever. Two people tragically lost their lives. Almost half of those affected were hospitalized, with 11 developing complications such as Haemolytic Uraemic Syndrome (HUS), a condition causing kidney failure. The rapid rise in STEC 0145 cases, detected through routine disease surveillance, prompted a multi-agency investigation across the UK. By analyzing the food history of those affected and subsequent scientific studies, UK agencies identified three common sandwich manufacturers. The most commonly reported sandwich types were bacon, lettuce, and tomato, as well as chicken salad sandwiches. UK-grown Apollo lettuce was identified as the likely contaminated ingredient. As a result, the three manufacturers voluntarily recalled their products as a precaution. Whole genome sequencing played a crucial role in linking affected cases, revealing the extent of the large national outbreak. Amy Douglas, lead epidemiologist at the UK Health Security Agency, emphasized the importance of whole genome sequencing in detecting and stopping outbreaks more quickly. She highlighted the challenges of outbreaks involving fresh produce or ready-to-eat foods, which emerge rapidly and require assessing a high number of cases. Douglas noted that by the time an outbreak is detected, implicated food products are often unavailable for testing, making it difficult to confirm contamination. STEC 0145 is described as a growing threat and one of the most common types of Shiga toxin-producing E. coli detected in the UK. The number of UK E. coli cases has significantly increased over the past few years, raising concerns about food safety and the need for enhanced surveillance and prevention measures.
