Wednesday, 26 December 2012

MRSA st398 in British milk - questions asked.

It is indeed eyebrow raising.

Maryn McKenna's take on MRSA st398 in British livestock.

Maryn is the author of "Superbug" and just the person to explain infectious disease and its implications to the non-scientific public like the writer.

This is now a global story, and Defra, Britain's agricultural ministry, will have to answer the questions raised; questions that should not have to be asked overseas.

Be sure to go to her article and read it all.  We hesitated to leave anything out. You can get the links via her blog here.

Livestock MRSA Found For First Time In UK Milk

BY MARYN MCKENNA 12.26.128:29 AM

This paper almost slipped by me. It was published quietly a few weeks ago, and it’s a little eyebrow-raising. From EuroSurveillance, the open-access peer-reviewed bulletin of the European Centre for Disease Prevention and Control (Europe’s CDC): The ST398 strain of MRSA, better know as “livestock-associated MRSA” or just “pig MRSA,” has been found for the first time in milk in England. (And therefore probably in cows, or at least on farms.)

Apparently there has been an ongoing study looking for any evidence of MRSA in UK cows, possibly because of this news from last year (of which more in a minute). ...

...What makes ST398 distinctive is that it has a signature antibiotic resistance, to tetracycline, which is not present in hospital or community MRSA, and which is easily traced to antibiotics used in livestock raising and especially in swine agriculture.

(For much more about ST398, you could look at my archives here and in this blog’s former location; and you could also peruse the blog of Tara Smith, the University of Iowa professor who has been the sole US researcher to take this seriously.)

So, now, this news: The interesting thing is that this is not the first identification of MRSA in milk in the UK. That finding (which I referred to up above) was made 18 months ago, by the same team responsible for this new discovery. Having made that identification — of what was, at the time, a never-seen MRSA strain — this team from Cambridge and Denmark went on looking in milk for other MRSA strains, and found ST398...

...But it is important to note that the UK agriculture authorities have been notably resistant to looking for ST398 over the years...

...The paper says, and this is narrowly correct, that there should be no concern over MRSA transmission via milk, because pasteurization will sterilize it. That may be true, but it does not account for the increasing appetite for milk sold raw, nor for raw-milk cheese.

...But a larger issue is that the presence of ST398 on UK farms could pose the potential for spread from cows into other animal species, as well as to farm workers. That makes ST398 an occupational health risk for farm workers, who could become infected with this strain — but it also threatens to make farm workers the vector for carrying the strain off farms and into the wider world...

...Despite its longstanding reluctance, it will be really important for the UK to start looking for MRSA on its farms now...