Irish scientists are trying to establish if the strain of salmonella which caused the recent food poisoning outbreak in Galway is the same as a potentially deadly super-bug that is growing increasingly resistant and spreading through farm animals.
A warning was issued by UK scientists yesterday about salmonella typhimurium DT104, which first appeared in cattle in the late 1980s. Now it has spread to poultry, pigs and sheep and developed resistance to seven antibiotics.
The Irish Food Safety Authority has already confirmed that the Galway outbreak, in which 15 people were hospitalised, was caused by salmonella typhimurium, but says it will take further tests to establish the presence of the DT104 type.
Earlier this week in Limerick, more than 40 guests at a wedding became ill due to salmonella poisoning. It is not yet known what species is involved in that outbreak.
In the outbreak at Dundrum Meats in April, in which 75 people were ill and one hospitalised, the DT104 type was confirmed as the cause. It was resistant to six types of antibiotics.
Dr John Threlfall, from the Public Health Laboratory Service in London, has carried out research to determine the extent to which the strain can infect the bloodstream. While stomach infections may cause severe sickness, diarrhoea and abdominal pain, blood poisoning can kill.
The results, published in the Lancet medical journal yesterday, show a low level of human blood infection in the UK, despite figures indicating a much higher incidence in the United States. But Dr Threlfall warned against complacency. "It is quite fortunate at the moment that strains are not supervirulent, but that is what we are worried about. Different strains could emerge that are more invasive. This is quite a mutatable beast," he said.
Dr Threlfall said the appearance of drug-resistant salmonella was a direct result of antibiotic use on farms. "These drugs are used legitimately for therapeutic purposes in animals, but at the same time they cause increasing resistance. This is an example of what can happen as a result of the use of antibiotics in agriculture."
Meanwhile, the chief executive of the Food Safety Authority, Dr Patrick Wall, said yesterday the recent spate of salmonella outbreaks in Ireland pointed to the need for increased levels of training in hygiene and food safety matters for staff of catering establishments.
--(Additional reporting by PA)