The UK’s Soil Association is calling for live farm animals and imported meat to be tested for MRSA following reports of the ‘superbug’ in livestock in Europe, particularly the Netherlands.
Research published this week [1] by the environmental charity says that a new strain of methicillin-resistant Staphylococcus aureus (MRSA) has developed amongst intensively farmed pigs, chickens and other livestock on the Continent. Furthermore, farm-animal MRSA (which is a different strain from MRSA found in British hospitals) has already transferred to farmers, farm-workers and their families in the Netherlands.
Although there have been isolated cases of MRSA in farm animals since 1972 (when it was detected in milk from mastitic cows [2]), the report claims MRSA is becoming a major problem in some countries. In one survey carried out at nine abattoirs across the Netherlands, 39% of pigs were found to be carriers of MRSA and nearly 50% of Dutch pig farmers have been found to be carriers of farm-animal MRSA. The farm-animal MRSA has been associated with skin infections, endocarditis and osteomyelitis in Dutch patients.
So should we be concerned in the UK? MRSA has not yet been found in UK livestock or meat products, but there are no routine tests of live pigs or chickens (although cattle are tested) or imported meat. The Food Standards Agency says it is aware of the issue and is keeping an eye on developments across Europe, along with a number of government agencies. It says proper cooking destroys MRSA in meat.
In 2005, the Department for Environment, Food and Rural Affairs (Defra) set up a subgroup of the Defra Antimicrobial Resistance Coordination (DARC) Group specifically to discuss MRSA and they produced a position statement on MRSA in animals. A study to test Staphylococcus aureus isolates obtained from bovine clinical submissions for MRSA commenced in Autumn 2006 but as yet there appear to be no plans to extend testing to other livestock species. A major focus of the subgroup has been the study of MRSA in companion animals as there have been increasing reports in pets in recent years [3]. In other countries, including Canada, USA and Japan, MRSA infections in horses are also becoming a concern [4].
One theory on the emergence of the new strain of MRSA in farm animals is the high levels of antibiotics used in livestock farming. The Soil Association is calling for a reduction in farm antibiotic use in the UK.
References
[1] MRSA in farm animals and meat, A new threat to human health, report five in the series ‘The use and misuse of antibiotics in UK agriculture’. Soil Association, June 2007 Cóilín Nunan and Richard Young
[2] Methicillin (cloxacillin)-resistant Staphylococcus aureus strains isolated from bovine mastitis cases. Devriese, L. A.; Damme, L. R. van; Fameree, L. / Zentralblatt fur Veterinarmedizin, B, 1972, Vol. 19, No. 7, pp. 598-605.
[3] Methicillin-resistant Staphylococcus aureus in dogs and cats: an emerging problem? Duquette, R. A. , Nuttall, T. J. / Journal of Small Animal Practice, 2004, Vol. 45, No. 12, pp. 591-597
[4] Methicillin-resistant Staphylococcus aureus in horses and horse personnel, 2000-2002. Weese, J. S. , Archambault, M. , Willey, B. M. , Dick, H. , Hearn, P. , Kreiswirth, B. N. , Said-Salim, B. , McGeer, A. , Likhoshvay, Y. , Prescott, J. F. , Low, D. E. / Emerging Infectious Diseases, 2005, Vol. 11, No. 3, pp. 430-435
The CAB Abstracts database has an additional 800 records on MRSA.