Use of antimicrobials licensed for systemic administration in UK equine practice

summary of:
Use of antimicrobials licensed for systemic administration in UK equine practice
Vet in discussion with horse owner
S.E. Allen,K.L.P. Verheyen, D.G. O’Neill and D.C. Brodbelt
Published in:
October 2022
Type of access:

Open access

In our edition of: Dec 2022
In our categories of: equine

our summary:

Allen, S.E. et al. (2022) Use of antimicrobials licensed for systemic administration in UK equine practice. Equine Veterinary Journal.

The aims of this retrospective study were to assess the current antimicrobial usage (AMU) and explore risk factors associated with systemic and Category B (third and fourth generation cephalosporins, quinolones and polymixins) AMU in UK equine practice.

The anonymised electronic patient records (EPRs) of equids attended by 39 veterinary practices participating in the VetCompass programme during 2018 were searched to identify systemic antimicrobial prescriptions using relevant terms. A random sample subset of the EPRs were reviewed by an experienced equine veterinary surgeon and clinical indications for AMU were extracted. The indications were then grouped by the main body system affected.

Data obtained from each EPR included individual antimicrobial events and courses, where Category B were prescribed as first-line therapy and information on the use of bacteriological culture.

The study population included 64,322 equids. Overall, systemic antimicrobials were prescribed to 19.5% of equids, with 1.9% of equids prescribed Category B antimicrobials. There was a total of 14,760 systemic antimicrobial courses, of which 8.9% included Category B antimicrobials. Bacteriological culture was performed in 4.9% of overall antimicrobial courses and 19.1% of Category B antimicrobial courses. For antimicrobial courses including Category B antimicrobials, they were used as first-line therapy in 71.7% of cases.

The most commonly prescribed antimicrobial classes were potentiated sulphonamides and tetracyclines and the most common Category B antimicrobial classes were third generation cephalosporins and quinolones.

The most common indications for systemic AMU were integumentary disorders (40.5%), prophylaxis (29%) and musculoskeletal conditions (22.8%). For Category B AMU, the most common indications were urogenital (31.1%), integumentary (25.2%) and respiratory (15.9%).

Increased odds of systemic and Category B AMU were observed in equids <1 year compared with those aged 5–14 years. Looking at breeds, Thoroughbreds and Thoroughbred crosses had the highest odds of systemic and Category B AMU.

Limitations of the study include the retrospective nature, the inconsistent quality of the data contained within veterinary EPRs and the possible selection bias with the convenience sample of veterinary practices used in which RCVS-accredited equine hospitals were over-represented.

Take Home

The study highlighted that levels of antimicrobial usage were consistent with previous studies with around 20% of equid prescribed systemic antimicrobials and 9% Category B antimicrobials. The study identified several factors associated with increased use of systemic and Category B AMU which will allow for targeted interventions in the high usage groups and provides benchmark data for further improvement in AMU in UK equine practice.

The following may also be of interest:

Lloyd, C. (2019) Re-categorisation of antimicrobials proposed by EMA’s AMEG [RUMA] [online]. Available from: [Accessed 20 December 2022]

PROTECT ME toolkit [BEVA] [online]. Available from: [Accessed 20 December 2022]

Responsible use of antibiotics in veterinary practice [inFOCUS. In the Spotlight] [online]. Available from: [Accessed 20 December 2022]

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