Meat products made from ground (minced) beef were suspected to be behind a serious E. coli outbreak in the United Kingdom in 2023, according to a recent report.

In June 2023, an outbreak of severe gastrointestinal symptoms caused by a rare type of Shiga toxin-producing E. coli (STEC) was detected by the UK Health Security Agency (UKHSA).

There were 27 confirmed cases and one probable patient linked to the outbreak. Twenty-one sick people lived across England, three in Northern Ireland, and two in Scotland and Wales. 

A total of 24 E. coli O183:H18 cases aged six months to 74 years old had onset dates ranging between May 22 and July 4, 2023, according to research published in the journal Microbial Genomics.

Eleven cases were in the 0 to 9 years age group. There was an equal number of female and male patients, with 13 each.

One death and one case of HUS
Of 24 people with available information, 17 reported bloody stools, and eight sought hospital care.

One person developed Hemolytic Uremic Syndrome (HUS). HUS is a severe complication associated with E. coli infections that causes kidney failure. One death is related to the outbreak, but the contribution of STEC infection to the death is uncertain, said scientists.

Efforts to find the source of infection included a questionnaire with 10 confirmed cases to collect a detailed food history two weeks before the onset of symptoms. Commonly reported items were strawberries, pasteurized milk, hard cheeses, chicken, and beef.

All these items were investigated, although chicken and pasteurized dairy products were deemed unlikely vehicles for transmitting STEC infection, as no previous E. coli outbreaks linked to these items had been recorded in the UK.

All 10 cases reported consumption of either beef burgers, ground beef cooked at home, or other ground beef products.

Complex supply chain
The Food Standards Agency (FSA) started a food chain investigation to look into common suppliers and processers to identify the origin of the beef. However, the complexity of beef industry supply lines hampered progress. Investigations were reduced once the outbreak ended, and the contaminated food source was not /confirm/ied.

Despite inconclusive epidemiological and food chain investigations, meat products made from ground beef were implicated as a potential vehicle.

The outbreak strain had the Shiga toxin subtype, stx2a, but did not have established STEC adherence factors, eae, or aggR. Additional toxin-associated genes and other attachment-associated genes were detected.

E. coli O183 is an extremely rare serotype, with only 15 cases in the UK since 2016.

Researchers hypothesized that this STEC serotype was recently imported into the UK or it is a domestic strain of E. coli that has acquired elements from an external source. They added that whether or not STEC O183:H18 will emerge as an ongoing threat to public health remains to be seen.

“Improvements in the standardized collection of epidemiological data and traceback strategies within the food industry will ensure we have a surveillance system capable of alerting us to emerging threats to public health,” said scientists.