It might be a little too soon to return to the topic of antibiotic-resistant bacteria in our food, but for me news of the discovery of meticillin-resistant Staphylococcus aureus (MRSA) in poultry at a farm in the East of England serves to illustrate just how important an issue this is.
According to the UK Animal Health and Veterinary Laboratories Agency (AHVLA) a strain of livestock-associated MRSA (LA-MRSA) was discovered in surveillance samples taken from turkeys and chickens on the farm – the first time it has been found in UK poultry. This particular strain is not uncommon in livestock across Europe, is not known to cause serious clinical infections in humans and doesn’t pose much of a threat to the health of the birds either. On the face of it the discovery isn’t something that we should be especially concerned about and there is little evidence of any direct threat to public health. Indeed, both the Food Standards Agency and Public Health England have been at pains to reassure consumers that the risk of contracting an MRSA infection from contaminated meat is extremely low, provided that it is handled hygienically and cooked properly – as should always be the case. Furthermore, there are no documented cases of people contracting an MRSA infection as a result of eating contaminated meat. The UK’s Chief Medical Officer, Dame Sally Davies, is quoted as saying, “Turkeys have lots of bugs on them so what we all have to do is assume they may be infected and we need to be sure that when we cook turkeys, we do so properly and we cook them to kill those bugs.”
All of this is quite true. There really isn’t any direct threat to public health from this strain of LA-MRSA in a few turkeys and it’s highly unlikely that anyone will become seriously ill. But is that really the point? What this shows is that antibiotic-resistant bacteria have now become firmly entrenched in the food production system. While innocuous strains of LA-MRSA may not be dangerous, other foodborne pathogens like Salmonella and verocytotoxin-producing E. coli certainly are. It is well known that the genetic elements that carry antibiotic resistance in bacteria are transmissible and can pass quite readily from one to another, even into the cells of a completely different species. So the greater the numbers of resistant bacteria in the food supply chain, the greater the risk that dangerous pathogens will acquire resistance to clinically important drugs. There is evidence that this is already happening. For instance, the poultry-associated strain of Salmonella Heidelberg responsible for infecting 389 people in the USA recently was found to be resistant to multiple antibiotics, which is likely to be one reason why 40% of those affected ended up in hospital. It’s time to get serious about tackling this problem.
If you would like to know more about the issue of antibiotic resistance in foodborne pathogens you might like to read our feature article on the subject.