The use of cephalosporins in animal
health
Introduction
Antibiotics (more correctly termed antimicrobials) are
essential for treating bacterial infections and are used in both animals and
humans. Antimicrobials for animals can only be prescribed by a veterinary
surgeon who decides when their use is appropriate and what particular
medicine should be administered.
What are
cephalosporins?
Cephalosporins are a group of therapeutic antimicrobials,
active against a range of bacteria, and similar to the penicillins. They all
share a similar chemical structure which is typified by a ß-lactam ring.
There are a number of “generations” of cephalosporins,
each generation having slightly differently properties. In general, the
later generations are better able to kill bacteria resistant to penicillin.
Cephalosporins are used in both human and animal medicine
because they are very effective and have few side-effects. The first to
fourth generations are used in animal health, while first to sixth
generation cephalosporins are used in human medicine.
Owing to their rapid action, cephalosporins are often
indicated for the treatment of life-threatening conditions.
Marketing Authorisation
Therapeutic antimicrobials must pass strict examination
by the Veterinary
Medicines Directorate and fulfil criteria of safety, quality and
efficacy before being allowed a Marketing Authorisation for use in animal
health. 'Safety' includes safety to the treated animal, the user, the
environment and, for food animals, the consumer of any livestock produce.
In products used for farm livestock, a withdrawal period
is calculated i.e. the time that must follow after the last treatment before
the animal, or its produce, can be used for human consumption.
(For more details on what is needed to get a marketing
authorisation, see NOAH briefing document 19
‘Controls on animal medicines’).
What species can be
treated with cephalosporins?
Cephalosporins are licensed for use in dogs, cats,
horses, cattle and pigs. The fourth generation cephalosporins specifically
are only licensed in cattle, horse and pigs.
Cephalosporins are used to treat individual animals and
not as blanket therapy for large groups.
How are cephalosporins
given?
Cephalosporins can be given either orally or by
injection, depending on the target species.
Cats and dogs will often be given a single injection by a
veterinary surgeon followed by tablets to be administered by the owner.
Cattle, horses and pigs are treated by daily injections.
Cattle may also be treated with intra-mammary tubes of
cephalosporins in order to treat, mastitis and to prevent new infections
which occur during the ‘dry period’.
Why is there concern
about their use in animals?
Cephalosporins are important in the treatment of humans,
especially children, as they have few side-effects. There has been some
debate as to whether or not use in animals can contribute to an increase in
resistance to cephalosporins among bacteria found in humans. There have
therefore been some demands to retain cephalosporins for human use only.
What evidence is there
that use in animals increases resistance in humans?
There is little in the way of direct evidence to indicate
that hospital and community-acquired resistance can be linked to use of
cephalosporins in animals. While some animal pathogens have been found to
show resistance these are usually genetically distinct from the resistant
bacteria populations found in humans.
Wouldn’t it be better
to reserve some cephalosporins for human use?
There is no definitive evidence that retaining certain
cephalosporins for human use will have any impact on the development of
resistance in the human community. Allowing veterinary surgeons a full range
of antimicrobials ensures that animals are treated quickly and recover more
rapidly from disease.
Shouldn’t antibiotic
use in animals be reduced in general?
All use of antibiotics is under the prescription of a
veterinary surgeon and is thus well controlled. Animal owners and farmers
have to pay directly the full cost of all veterinary medicines, including
antibiotics so over-use and misuse is less likely than in human medicine.
Antibiotics must be used responsibly in both people and
animals and NOAH, along with the veterinary profession (and many other
organisations involved in the food chain) support this through the
Responsible Use of Antimicrobials Guidelines developed by the
RUMA (Responsible Use of
Antimicrobials in Agriculture) Alliance and their own supporting
initiatives.
Responsible use does not mean antibiotics should not be
used when they are needed: they should be used “as little as possible but as
much as necessary”.
Risk of transfer of
resistant bacteria through food
There is little risk of resistant bacteria being
transferred to humans through meat or milk. Milk is pasteurised and meat
should be properly handled and cooked thus killing any bacteria.
Industry guidance for
cephalosporin use
Cephalosporin antimicrobials have an important role in
controlling infections in animals, especially fast acting and often fatal
bacterial diseases. They are therefore an important part of a veterinary
surgeon's arsenal of tools for ensuring good welfare of animals.
The industry recognises that use of all medicines must be
responsible and follow good guidance principles:
1. Farm health plans, including Standard Operating
Procedures (SOPs) for hygiene and management programmes such as vaccination,
appropriate animal husbandry and care should be used, as relevant, to reduce
disease and the need for therapeutic intervention.
2. Cephalosporins will be used only where the prescribing
veterinary surgeon believes that they are the most appropriate antimicrobial
for treating the disease.
3. Cephalosporins can be administered only under
prescription by a veterinary surgeon: like all antibiotics they are
classified POM-V (Prescription Only Medicine - Veterinary)
4. Advertising must comply with the requirements of the
NOAH Code of Practice for the Promotion of Animal Medicines and current UK
legislation. (For more information on the NOAH Code of Practice see
http://www.noah.co.uk/issues/code.htm)
Monitoring
antimicrobial susceptibility
The animal health industry recognises the importance of
developing resistance and has set up monitoring programmes across Europe for
both commensal and zoonotic bacteria. These surveillance programmes have
shown that resistance following use in animal health is rare but the
programmes are continuing to monitor the occurrence of resistance.
June 2011
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