MRSA in pigs in Holland - is there cause for concern?
High levels of MRSA (methicillin-resistant Staphylococcus aureus) have
been isolated in pigs in Holland and also in pig farmers and vets, should we be
A high level of MRSA (methicillin-resistant Staphylococcus aureus) has
been isolated in 39% of pigs in Holland and also in pig farmers and vets and
this is causing much consternation.
It is not so much for the pigs, where
S. aureus is not associated with a specific disease problem, unlike
Streptococcus suis for example, which still remains penicillin sensitive,
but for the humans associated with pigs and other farm animals that might carry
the infection into hospitals, where the major problems lie.
Methicillin resistance means that higher
penicillins and cephalosporins, which are very commonly used in human medicine,
are all ineffective.
This situation is interesting; why has it occurred
in Holland, and to such an extent?
The presence of the organism has been
reported in many other countries, such as Denmark, Germany, Austria and France
but at a relatively low percentage. In the UK, they have not found it in pigs to
date but they have not been actively screening for it.
hundred milk samples from dairy cows, where methicillin-related compounds are
used for the treatment of mastitis, have tested
So what has changed? The organic
lobby is blaming antimicrobial use as usual, but we have been using
antimicrobials for a long time, without inducing such a problem before.
There has to be a selector for the resistance mutation and this is
reportedly a rare genetic occurrence. Has there been a major change in
antimicrobial use in Holland to products that would select for resistance,
i.e. the more advanced penicillins or cephalosporins?
This has not been reported as the case. In one survey in
Belgium it was reported that 5% of herds had started to use cephalosporins in
piglets by injection as prophylaxis, probably against S. suis or
Haemophilus parasuis. This would not affect 39% of the national
There is an epidemiological study in progress in Holland but, to
infect such a large number of pigs and farms so quickly (since 2004), suggests
that it may have come down a large breeding pyramid, like PRRS did in the
This would be a major concern if this was the
case and the breedingpyramid was exporting stock to other
Meat, reportedly, does not carry a significant risk of
transmission, but live breeding animals could.
Whilst we are in a
situation where we do not know all the facts, as a precaution, it would be worth
insisting that breeding animals from Holland be tested for MRSA before shipping
to other countries, to prevent the same thing happening
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