For the first time in the UK, we have been able to compare the usage of
antimicrobials in humans and in animals following the release of a
cross-government department report 'Overview of antimicrobial usage and
bacterial resistance in selected human and animal pathogens in the UK:
This is important, as the use of antimicrobials in veterinary
medicine and thereby in agriculture has frequently been criticised, even since
we have banned the use of antimicrobial growth promoters in Europe.
There is a joint WHO/FAO/OIE meeting
in November to look at the availability of 'critical' antimicrobials used in man
and animals and this report is extremely timely, as there is very little
published information available, on which to draw sensible and practical
The amount of antimicrobials used in veterinary medicine in
the UK, which includes farm animals and companion animals (cats and dogs) was
reported as 454 tonnes in 2004.
medicine, use in the community i.e. via general practitioners was 330
tonnes and in hospitals in England only, it was 68.7 tonnes.
figures are adjusted for population differences the UK hospital use should be
about 82.4 tonnes bringing the total usage to 412 tonnes or 91% of the animal
use. However, the type of antimicrobial used in farm animals is frequently very
different from those used in human medicine (see Figure
Figure 1. Comparison of
antimicrobial use in veterinary and human medicine in the hospital and the
In farm animal medicine we use a lot of basic tetracyclines,
especially chlortetracycline, which is not available as an oral preparation now
in human medicine, but only for topical use.
Trimethoprim is usually
used with a sulphonamide in a 1:5 ratio in animals, to utilise the synergistic
activity of the combination. In man, they use primarily trimethoprim alone and
the trimethoprim use is similar for both. Beta lactams, which include
penicillin, synthetic penicillins (amoxycillin) and cephalosporins, are hugely
important in human medicine, especially in hospital.
cephalosporin use in animals is only 7.5% of human use. These more advanced
penicillins and cephalosporins are important as they are associated with the
selection of methicillin resistance, which is a major problem in UK hospitals.
Aminoglycosides are hardly used in human medicine due to their relative
toxicity and have been largely superseded by the cephalosporins and
fluoroquinolones, yet they are still commonly used in veterinary medicine.
Fluoroquinolones are widely used in human medicine both in hospitals and
in the community because of their high efficacy and relative safety. In
veterinary use, it is only 6.8% of the human figure. In the 'Other' group, a
substantial proportion of the veterinary antimicrobials are due to the
pleuromutilins, which are currently not used in human medicine.
Generally, in farm animal medicine many of the older antimicrobials
are still widely used and are effective, such as penicillin and the
tetracyclines. Cost is also an important factor. In companion animals, cost is
not always so critical and frequently the more modern and expensive
antimicrobials are used.
Overall though, there is very little cross over of use,
except possibly in the macrolide group, but they have now been banned as growth
promoters. As long as antimicrobials are used prudently and responsibly, is
there any need to further restrict their availability for veterinary use as we
are poles apart?