More than 2,000 cases of Shiga toxin-producing E. coli (STEC) were reported in England in 2022, an increase of almost 80 percent from the year before.
According to the UK Health Security Agency (UKHSA), 2,063 cultured-confirmed cases of STEC were reported, an increase of 79.2 percent compared to 1,151 in 2021.
UKHSA said during 2020 and 2021 it was likely that the COVID-19 pandemic and measures to control transmission of the virus affected reports of STEC infections to national surveillance in several ways.
E. coli O157 figures
There were 762 culture-confirmed cases of STEC O157 in England in 2022, more than double the 365 recorded in 2021 and higher than pre-pandemic levels. It is the highest rate in almost a decade and halts the downward trend seen since 2015. A large outbreak with 195 cases contributed to the increase, but does not totally explain the rise, said UKHSA.
More up to date figures show 538 STEC O157 cases in 2023 and 567 in 2024.
The highest incidence in 2022 was in the North East and the lowest was in London. Of 762 confirmed STEC O157 cases, 417 were female.
STEC O157 infections usually peak in the summer months of July or August. However, in 2022 infections peaked in September because of a large UK-wide outbreak.
In total, 223 of 722 confirmed STEC O157 cases were hospitalized and 13 developed Hemolytic Uremic Syndrome (HUS). HUS is a clinical syndrome related to E. coli, which can lead to kidney failure and death. Three adult deaths were reported among STEC O157 cases.
Children aged 1 to 4 had the highest annual incidence of infection by STEC O157 and non-O157.
Twenty-six cases were infected with multiple serogroups. The most common serogroups in a co-infection were O157, O146, and O26.
Non-O157 data
There were also 1,998 cases of STEC non-O157, an increase of 62 percent compared to 1,234 in 2021. The most commonly isolated serogroups were O26, O146, O91, O103, and O128ab.
The total includes 1,301 culture-confirmed STEC non-O157 specimens, and 697 that were PCR positive but STEC could not be cultured. Of the culture-positive cases, 90 different serogroups were confirmed.
Of the 1,998 cases, 1,177 were female. There was a peak of infections in the late summer and autumn months of July to October with a second peak in November.
In total, 176 of 600 non-O157 cases were hospitalized and 32 developed HUS. The most frequently isolated serogroups from HUS cases were O26, O145, and O121. Three deaths were reported among non-O157 cases, including two adults and one child.
Four STEC outbreaks affecting 299 people, including 235 who lived in England, were investigated in 2022. One associated death was recorded.
An E. coli O157 outbreak with 195 cases in England, 18 in Northern Ireland, 33 in Scotland, and 13 in Wales was traced to salad leaves. Overall, 75 people were hospitalized. Another E. coli O157 outbreak with 18 cases and 10 hospitalizations was linked to a beef product.
Soft cheese was behind an E. coli O103 outbreak with 10 cases in England and two in Wales. An E. coli O145 outbreak with 10 cases and three hospitalizations was linked to pasteurized milk. An investigation pointed to post pasteurization contamination of milk, likely because of contaminated bottles that were insufficiently sterilized, and failure to maintain the cold chain.
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