by Jeremy Laurance
26 December 2012
Research reveals that
are gaining a hold on dairy industry
A new strain of
MRSA has been found in British
milk, indicating that the superbug is spreading through the
livestock population and poses a growing threat to human health.
The new strain,
MRSA ST398, has been identified in
seven samples of bulk milk from five different farms in England.
The discovery, from tests on 1,500 samples, indicates that
antibiotic-resistant organisms are gaining an increasing hold in the
The disclosure comes amid growing concern over the use of modern
antibiotics on British farms, driven by price pressure imposed by
the big supermarket chains. Intensive farming with thousands of
animals raised in cramped conditions means infections spread faster
and the need for antibiotics is consequently greater.
Three classes of antibiotics rated as “critically important to human
medicine” by the World Health Organization,
...have increased in use in the animal
population by eightfold in the last decade.
The more antibiotics are used, the greater the likelihood that
antibiotic-resistant bacteria, such as MRSA, will evolve.
Experts say there is no risk of MRSA infection to consumers of milk
or dairy products so long as the milk is pasteurized. The risk comes
from farmworkers, vets and abattoir workers, who may become infected
through contact with livestock and transmit the bug to others.
The discovery was made by scientists from Cambridge University who
first identified MRSA in milk in 2011. They say the latest finding
of a different strain is worrying.
Mark Holmes, of the department of veterinary medicine, who
the study published in The Lancet,
“This is definitely a worsening
situation. In 2011 when we first found MRSA in farm animals, the
Department of Environment, Food and Rural Affairs [Defra]
initially didn’t believe it. They said we don’t have MRSA in the
dairy industry in this country.”
“Now we definitely have MRSA in livestock. What is curious is
that it has turned up in dairy cows when in other countries on
the Continent it is principally in pigs. Could it be in pigs or
poultry in this country? We don’t know.”
The MRSA superbug can cause serious
infections in humans which are difficult to treat, require stronger
antibiotics, and take longer to resolve.
Human cases of infection with the new
strain have been found in Scotland and northern England according to
Defra, but no details are available.
Dr Holmes said supermarket pressure on farmers to hold down prices
was leading to the overuse of antibiotics to prevent cattle getting
mastitis, an infection of the udder, that might interrupt the milk
“If farmers were not screwed into
the ground by the supermarkets and allowed to get a fair price
for their milk they would be able to use fewer antibiotics,” he
“Common sense tells us that anything we can do to reduce use of
antibiotics will reduce the growth of resistant bugs. We want to
wean our farmers off antibiotics and the only way we can do that
is with better regulation.”
Vets in Norway and Denmark had much more
limited prescribing powers than in the UK, he added.