E. coli O157 linked to heart risk
Catching the most dangerous strain of E. coli could increase the risk of high blood pressure and heart problems years later, say researchers.
A Canadian study of almost 2,000 who fell ill during an outbreak of E. coli O157 found heart attack risk doubled.
Writing in the British Medical Journal, the researchers recommended annual health checks, even for patients who had apparently fully recovered.
A microbiologist said basic food hygiene could prevent many cases.
There are an estimated 1m cases of food poisoning in the UK each year, but the O157 strain of E. coli is regarded as one of the most dangerous.
It can cause severe gastroenteritis and contact with small numbers of the bacteria, carried in animal faeces, is enough to make you ill.
There are approximately 1,000 confirmed cases each year in the UK, and while it is known to cause kidney problems in a small number of people, there has been little investigation into other possible longer-term complications.
The research team, based in Victoria Hospital, London Ontario, followed up people affected when the municipal water system in Walkerton became contaminated in May 2000.
Seven people died, and thousands fell ill, and while some were only mildly affected, many had significant symptoms, including severe diarrhoea.
Checking their medical history in the intervening years revealed that the rate of kidney problems tripled among those with gastroenteritis compared with those who were relatively unaffected.
The severely-hit patients were also slightly more likely to develop high blood pressure, and more than twice as likely to have a heart attack during this period.
The researchers suggested that the powerful toxin released by E. coli O157 could trigger inflammation that could affect blood vessel linings, and making heart and blood pressure problems more likely.
They recommended annual blood pressure checks for people who had been seriously affected by the strain.
The number of E. coli O157 cases in the UK has remained stable in recent years, ranging from approximately 800 to 1,200 annually.
However, despite the low numbers, Bob Martin, a microbiologist at the Food Standards Agency, said that people still needed to follow basic hygiene rules when buying and cooking meat products, or after handling animals.
He said: "It is a rare strain, but the key thing is to stop yourself falling ill in the first place.
"You can reduce the risk by keeping things clean in the domestic setting, and cooking food thoroughly, as this will kill off bugs, particularly things like sausages and burgers which are made from minced meat.
"Keeping food properly refrigerated is also important, as is preventing cross-contamination between raw meat and cooked food."