MRSA Variant's Entrance into Food Chain Causes Fear

As reported in The Sunday Post, the Scottish MRSA Reference Laboratory has identified three patients in Scotland suffering from a new type of MRSA infection, not previously identified in the UK. The MRSA is a strain known as ST398 or NT-MRSA, which has been spreading rapidly across continental Europe and some other countries, affecting both farm animals and humans.

The problem came to light after the Soil Association asked the Scottish reference laboratory to recheck one suspicious sample, which was mentioned in a scientific paper, but which had not been fully tested.

Professor Giles Edwards, head of the laboratory, agreed to this request. He subsequently told the Soil Association about two further patients who had also been found to be infected by the same strain of MRSA.

In the Netherlands and some other countries, a high proportion of pigs and other farm animals are already carriers of MRSA ST398, and there have been many cases of humans becoming colonised due to contact with animals, and then developing serious MRSA infections. Although MRSA ST398 was only first detected in humans in the Netherlands as recently as 2003, by 2007 approximately 30% of all cases of human MRSA in the Netherlands were ST398.

In a report published in June last year, the Soil Association warned that unless urgent action was taken, farm-animal MRSA would spread to Britain and threaten to complicate and worsen the already serious MRSA problem in British hospitals.

Many other countries have responded to the Dutch outbreak by testing their own pigs and publishing the results as rapidly as possible: Belgium, Denmark, Germany, Spain and Canada have all confirmed that some of their pigs are MRSA carriers. However, the Government rejected the Soil Association’s call for British pigs to be tested, indicating that is would not do this until ST398 was found in humans. Testing only began earlier this year because of an EU requirement for all member states to test some of their pigs for MRSA. If interim results are not published by the Government, no results will be available before mid-2009.

Soil Association Policy Adviser, Richard Young, said, “It is regrettable the Government has allowed this problem to develop, when action at an early stage could have nipped it in the bud. ST398 is no more serious than existing strains of MRSA, but it is resistant to different antibiotics, and where it is present it will make it harder for doctors to select an effective drug quickly. In some cases this could be the difference between life and death. It is also likely to increase the overall number of MRSA cases in humans, because farm animals are kept in such large numbers on intensive farms and constitute a growing reservoir of this superbug worldwide.“

“We suspect that MRSA has now been found in British pigs. Defra must publish the results of testing as these become available. There can now be no excuse for not also initiating a comprehensive testing programme in the UK to establish the full extent of MRSA in British farm animals.“

Further Reading

- Find out more information on MRSA by clicking here.