Strategies to reduce antimicrobial resistance in equine practice.

Research output: Book chapter/Published conference paperConference paper



Before embarking on strategies to reduce development of antimicrobial resistance (AMR) in equine practice, the initial sceptical question may be whether AMR is a problem or mere scare-mongering. Clearly the resounding answer is that AMR is an important problem that is not confined by time, geographical borders or species and is escalating (Morley et al. 2005; Batey and Gibbens 2013; Bowen 2013). Indeed, AMR is part of the landscape of human medicine, veterinary medicine and animal production practices and, worryingly, AMR organisms have the potential to spread between animals and between animals and humans. During the latter half of the 20th century, the discovery and introduction of antimicrobial drugs (AMD) had a dramatic effect on human and veterinary medicine, revolutionising prevention and treatment of numerous infectious diseases (Morley et al. 2005). However, just as soon as victory over pathogenic bacteria was being declared, decreases in bacterial susceptibility to these drugs were recognised, and AMR in micro-organism populations continues to develop and spread. While the identification and synthesis of several new AMDs initially provided optimism of offsetting development of AMR and long lasting control of infectious diseases, AMD development has slowed and recognition that AMR is persistent and critically-important issue is required.

Antimicrobial resistance mechanisms

Antimicrobial resistance may be inherent (constitutive resistance) or acquired through several genetic means, including mutation, acquisition of extrachromosomal plasmids and movement of smaller mobile genetic elements (e.g. transposons) (Morley et al. 2005). Acquired AMR is of principal concern in the context of limiting development of AMR in both veterinary and human medicine. While AMR genes transfer most commonly between bacteria of the same species, there is evidence that genetic material can move between bacteria of differing species or genera, highlighting one avenue for dissemination of AMR in addition to movement of bacteria between individuals of the same or different species (Morley et al. 2005). Once bacteria acquire AMR, it is not yet clear the patterns and stability of persistence of AMR that may develop, however it cannot be assumed that withdrawal of AMD exposure will result in diminishing AMR.

Strategies to minimise AMR development

There is increasing awareness of the importance and threat of AMR to animal and human health and recognition that it falls upon the veterinary profession to meaningfully address this growing problem through judicious use of AMDs and development of strategies and policies to minimise AMR. Such co-ordinated and responsible strategies will provide health benefits to the individual animal, animal cohorts and populations and human health. Further, these policies and strategies will serve to demonstrate to human health bodies and legislators that the veterinary profession are responsible custodians of AMDs and the philosophies of minimising AMR (Bowen 2013).

The importance of AMR in veterinary medicine has been promoted recently through several industry initiatives (e.g. AVMA, AAEP, BVA and BSAVA guidelines/policies, BEVA ‘toolkit’, VMD code of practice) and journal articles (e.g. Wilson 2001; Morley et al. 2005; Bowen 2013)., which serve as substantive reference material for education and development of strategies to limit AMR in veterinary practice. Indeed, the BEVA toolkit (Protect ME), designed for development of policies for AMD use at an individual practice level, are a welcome addition for equine practitioners.

A summary of recommended strategies is provided below and includes steps for reducing AMD use and for rational AMD selection.

1. Access to AMDs should be limited to veterinarians and AMDs should only be used in the confines of existing veterinarian-client-animal relationships
2. Infection control protocols should be developed to limit infectious disease and AMD use
3. Confirmation or a high level of suspicion of the presence and active involvement of bacteria in infectious disease that requires AMD treatment for resolution is a prerequisite. Detection of bacteria requires appropriate sample collection (Hodgson et al. 2008)
4. AMD selection should be supported by in vitro sensitivity testing
5. Pharmacokinetic and pharmacodynamic principles must be employed for confidence that therapeutic concentrations will reach the infection site and to select the appropriate dosing regimen. Methods for local AMD administration should be used, where appropriate to limit exposure of non-target bacteria
6. Common case scenarios should be identified to develop standardised AMD use protocols which take into account local AMR patterns, results of monitoring programmes and types of treated animals (Wilson 2001; Morley et al. 2005)
7. AMD spectrum should be minimised to limit exposure of non-target bacteria
8. AMD used should be allocated to primary, secondary or tertiary use categories and evidence-based criteria used before using secondary or tertiary drugs. This will also facilitate protection of AMDs that are considered of critical importance to human health
9. Resolution of infection should be determined through clinical and laboratory monitoring
10. Treatment failures should be investigated prior to continuation/change of antimicrobial regimen
11. Prophylactic AMD use (e.g. peri-operatively) should be minimised to high risk situations and not as a replacement for optimal surgical technique
12. Monitoring of AMD use and surveillance for developing trends of AMR is important from the local level upwards
13. Ongoing education regarding AMR and judicious AMD use: veterinary profession and horse owners
14. Scrutiny of AMD advertising for scientific evidence of efficacy and appropriateness for stated uses, prior to use.


Batey, N. and Gibbens, N. (2013) Antimicrobial resistance – what is the issue? Equine Vet. Educ. 25, 217-218.

Bowen, M. (2013) Antimicrobial stewardship: time for change. Equine Vet. J. 45, 127-129.

Hodgson, J.L., Hughes, K.J., Hodgson, D.R. (2008) Diagnosis of bacterial infections. Part 1: Principles of sample collection and transportation. Equine Vet. Educ. 20, 608-616.

Morley, P.S., Apley, M.D., Besser, T.E., Burney, D.P., Fedorka-Cray, P.J., Papich, M.G., Traub-Dargatz, J.L. and Weese, J.S. (2005) Antimicrobial use in veterinary practice. J. Vet. Intern. Med. 19, 617-629.

Wilson, W.D. (2001) Rational selection of antimicrobials for use in horses. Proc Am. Assoc. Equine Pract. 47, 75-93.

Original languageEnglish
Title of host publicationHandbook of Presentations
Subtitle of host publicationBritish Equine Veterinary Association Congress 2013
PublisherBritish Equine Veterinary Association (BEVA)
Number of pages1
Publication statusPublished - 2013
Event52nd British Equine Veterinary Association Congress - Manchester, United Kingdom
Duration: 11 Sep 201314 Sep 2013


Conference52nd British Equine Veterinary Association Congress
Country/TerritoryUnited Kingdom


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