2.2 Use of antimicrobial drugs in veterinary practice

Policy

Antimicrobial drugs (antibiotics) should only be administered, dispensed or prescribed when the veterinarian has made a reasonable assessment that bacterial disease has been confirmed or can reasonably be suspected as the cause of the animal’s clinical signs. This assessment should be based on clinical history, physical examination and, if necessary, appropriate laboratory tests. However, the Australian Veterinary Association (AVA) recognises that physical examination of every individual in a herd or flock is often not possible.

Antimicrobial drugs may also be used to prevent overgrowth of bacteria following viral illnesses, during anti-tumour therapy, in immunocompromised patients, in patients receiving steroids and in cases of penetrating wounds where decontamination or disinfection is not fully effective. It is better to use antimicrobials in this manner than to allow bacterial infections to develop that subsequently require extensive treatment and/or supportive therapy.
Veterinarians should stress to owners the importance of routine prophylaxis, such as dental care, parasite control, hygiene, animal husbandry, vaccination and adequate nutrition and exercise, to reduce the risk of clinical bacterial disease and therefore reduce the need for antimicrobial therapy.

Background

Antibiotics are used in farm animals to improve performance — for example, by preventing diseases such as necrotic enteritis in poultry, which is very common when birds are fed wheat-based diets.

Exposure of bacteria to antibiotics can lead to the development of resistant strains. Some bacteria are capable of passing on resistance genes to other bacteria. Bacterial resistance to antibiotics can be passed from animals to humans via bacteria that do not cause disease themselves but are able to pass on resistance genes to disease-causing bacteria.
Concern has been raised over the use of antibiotics in food-producing species. Usually, proper food preparation and cooking of animal products will remove the risk of transfer of bacterial resistance from this source.

The other way in which antibiotic use in animals could lead to antibiotic resistance in humans is through contact with treated animals. Farm workers and owners of pet animals being treated with antibiotics need to pay particular attention to hygiene during and after handling the treated animals.

Other recommendations

It is desirable that innovative methods of using antimicrobials are developed so that the development of cross-resistance is minimised or eliminated.

Research and development of production systems that minimise the need for antibiotics is essential. The aim should be an alternative technology that maintains animal welfare and productivity without causing environmental contamination, or other undesirable side effects of antimicrobial use.

Registered antibiotics go through stringent peer-reviewed tests. Proposals for alternatives to antibiotics must consider the safety, quality, efficacy and environmental impact of any product, compared with available antibiotics.

Date of ratification by AVA Board 17 October 1999