Policy: Judicious use of antimicrobials

Policy type: Policy
Reference: 2e
Status: Current
Date ratified: November 2019

Policy

The New Zealand Veterinary Association encourages effective collaboration between the veterinary profession, human health organisations, Government, all relevant industries, the wider public and with international organisations in order to preserve the ongoing efficacy of antimicrobials.
Judicious use of antimicrobials, infection prevention and control, and effective preventive animal health care programmes are critical to reduce and avoid serious consequences related to antimicrobial resistance.

Explanation

Use of antimicrobials must be preceded by robust clinical judgment.

The use of antibiotics provides an effective method for the treatment and control of infectious diseases caused by bacteria and certain other micro-organisms. Use of antimicrobials supports good animal welfare outcomes, and allows for production of meat, egg and milk products which are safe for the consumer.

In treating animals with antimicrobials, veterinarians should aim to optimise therapeutic efficacy and minimise the potential for development of resistance to antimicrobials.

Inappropriate use of antibiotics should not be accepted as a substitute for good management and husbandry practices. Any antimicrobial use increases selection pressure for resistance

The NZVA’s Judicious Use Guidelines provide species-specific information for veterinarians regarding antimicrobial treatment options for infectious diseases in animals.

The NZVA also promotes the categorisation of antimicrobials into a cascade of use-preference, based upon their risk with respect to risk to development and transfer of resistance genes.

Background - Regulation

The Veterinary Council of New Zealand sets out expectations for veterinarians when authorising antibiotics in the Veterinary Medicines section of the Code of Professional Conduct. These expectations set criteria around authorisation of antibiotics and advertising of restricted veterinary medicines.

The Agricultural Compounds and Veterinary Medicines Act and the ACVM Notice (Requirements for Authorising Veterinarians) sets out expectations for stewardship of RVMs.

Guidelines for Judicious Use of Antimicrobials

1. Antibiotics should only be used when it is known or strongly suspected that susceptible bacteria are present and causing, or likely to cause, disease.
2. The appropriate selection of antimicrobials is a clinical decision and should be based on:
   1. accurate diagnosis including identifying the likely causative bacteria
   2. known or predictable sensitivities (culture and sensitivity testing)
   3. known pharmacokinetics/tissue distribution to ensure the active compound reaches the site of infection
   4. likelihood of compliance with dosing instructions
   5. animal health status, including immunocompetence
   6. appropriate route of administration
3. Alternative methods of disease and infection control (e.g. altered management and husbandry) enable reduction in antimicrobial use
4. All antimicrobials must be used and stored correctly. Sterile technique with multi-use vials should be observed.
5. NZVA’s Judicious Use Guidelines assist veterinarians’ decision-making process when authorising of appropriate antimicrobials.

Empirical Use of Antimicrobials

1. Antimicrobial therapy may need to be initiated before the results of diagnostic or sensitivity tests are known, it will need to be reassessed as test results become available.
2. Empirical choices of antibiotic must be made based on:
   1. knowledge of previous antimicrobial efficacy or sensitivity testing
   2. relevant controlled clinical trial data where available
   3. the NZVA’s judicious use guidelines.
3. In order to minimise the likelihood of antimicrobial resistance developing, appropriate narrow spectrum antimicrobial use is preferable to a broad-spectrum drug. The NZVA’s antimicrobial priority list should be consulted.
4. Antimicrobials considered of high importance in human medicine should be avoided unless there is good reason to use them (e.g. where other available drugs are not likely to be effective).

Dosage strategy

1. Optimal therapeutic dosage strategies should be used. Dosage recommendations as laid down in the registered ACVM label should be followed. In some specific cases, such as fluoroquinolones and erythromycin, sub-therapeutic dosages been shown to induce resistance. Veterinarians must make every effort to avoid giving sub-therapeutic dosages, which lead to a lack of efficacy.
2. Treatment should be for as short a time as possible but for as long as necessary for the desired clinical response.
3. Careful calculation of dose is important, in order to achieve appropriate therapeutic levels of antimicrobials in the targeted tissue.
4. When discretionary, off-label use of a product is being considered, caution needs to be exercised regarding meat, egg and milk withholding periods.
5. Where antimicrobials are used by non-veterinarians (under supervision), training must be adequate to ensure compliance with use instructions.

Disease control programmes

1. Antibiotic use may be part of an integrated disease control programme. Such a programme is likely to involve hygiene and disinfection procedures, biosecurity measures, management alterations, changes in stocking rates, vaccination, etc. This applies to all species.
2. Antibiotic use in such control programmes should be regularly assessed for effectiveness and whether such use can be reduced or stopped.
3. In on-going disease conditions, written protocols should be agreed between the veterinarian and the client as to how often veterinary involvement is required. These protocols must be regularly and frequently reviewed and updated. The appropriate review period will depend on the circumstances but should not be longer than twelve months. If critically important antibiotics are authorised, the review period must be every 4 months.
4. Written protocols should be agreed for treatment of all enzootic conditions on the farm or premises. These protocols must be regularly reviewed and updated. They should outline the farmer’s obligations concerning the use of antibiotics. They should cover:
   • Storage
   • Administration techniques
   • Recording information to ensure compliance e.g. animal identification, product name, dose administered, date of treatment
   • Withholding times for meat and egg or milk
   • The correct dosage and duration of medication
   • The correct indications for use
   • The correct procedures for ensuring adequate withholding times.
5. Use of antibiotics for the prevention of disease can only be justified where it can be shown that a disease is present on the premises, or is likely to become so, and that strategic antibiotic use will prevent clinical outbreaks of that disease and minimise animal welfare concerns. This strategy should only be employed in the short term and should be incorporated into or superseded by a preventative disease control programme. Prophylactic therapy should not use antibiotics of high importance to human health.

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