MRSA in sausages: getting to the meat of the matter
You might have seen in the news today that for the first time a strain of the antibiotic-resistant bacterium, MRSA, has been found in sausages and minced pork bought from supermarkets. So is this the first sign of a food safety crisis? Emphatically not, says our Head of Infections and Immunity, Dr Desmond Walsh, but it does show how critical it is to tackle the problem of antimicrobial resistance on all fronts.
Is MRSA running rampant in our meat products?
No, that’s not a conclusion that this study supports. The researchers, funded by the MRC and based at the University of Cambridge, bought and analysed a total of 103 pre-packaged fresh pork and chicken products from supermarkets in five different locations across in England. All the packages were labelled as coming from UK farms.
The researchers found that two of the pork samples – one from sausages, one from minced pork – tested positive for MRSA.
As the tests use a highly sensitive method of detection of bacterial contamination, the numbers of MRSA bacteria present may be low. We also don’t know that the MRSA contamination definitely came from UK meat, as there’s no guarantee that the meat packing plants that handled the meat don’t also handle imported meat.
Should I stop buying sausages from supermarkets?
No. Cooking sausages adequately (heating them to a temperature of more than 71°C) and following the usual hygiene measures of cooking with raw meat should minimise the risks of transmission.
Even if you were to eat the bacteria, the risk of illness is small. Lots of people actually carry MRSA in their nasal passages without any ill effects – it only causes health problems if it infects someone in poor health or gets into a wound.
And remember, MRSA was found in just two pork samples.
So … why is this research important?
It shows just how widespread antibiotic-resistant bacteria such as MRSA are, and it makes us aware of a route of transmission from farms to the wider population. If MRSA is infecting pigs on British farms, it could be transmitted to the wider populations via farm workers, slaughterhouses and butchers etc.
But how are the bacteria finding a home on farms in the first place? There has been an EU-wide ban on using antibiotics as growth promoters since 2006, but we know that the widespread use of antibiotics in agriculture to treat infection is one of the driving forces behind resistance.
The bacteria belong to a type of MRSA known as LA-MRSA CC398, which has emerged over the last few years in continental Europe, particularly in pigs and poultry, but was not previously believed to be widely distributed in the UK.
The possibility that this MRSA strain is establishing itself in UK farms is another reminder that antibiotic resistance is a battle which needs fighting on many fronts.
So where do we go from here?
We’re not going to be able to combat the problem of antimicrobial resistance by restricting research to working out how bacteria develop resistance or studying their effects on the human body: the issue of AMR needs researchers from a broad range of fields working together with people in the health service, policy-makers and internationally.
One way that we’re doing this is by spearheading the AMR Funders’ Forum, our ‘war cabinet’ of funders, including public sector organisations, charities and industry. Together we’re identifying where we need to invest in AMR research at every level and in every environment – from labs to livestock, from finding new diagnostic tools to educating professionals and the public.
Find out more about our work in AMR on our website.
The research was funded by the MRC with additional support from the Alliance to Save our Antibiotics. The study is published in the online journal Eurosurveillance.