Use of antimicrobials licensed for systemic administration in UK equine practice

Antibiotic usage in 14 equine practices over a 10-year period (2012-2021)

BACKGROUND

Monitoring antibiotic usage is an important part of tackling antimicrobial resistance. The use of computerised records for monitoring has been previously described in the equine sector but there is currently no consensus on metrics used to report usage.

OBJECTIVES

To document antibiotic use in equine practices in the United Kingdom over a 10-year period using commercially available practice management software.

STUDY DESIGN

Retrospective survey.

METHODS

A custom antibiotic usage report was created using Eclipse® practice management software. Participating practices were given instructions on how to generate the usage report. Annual reports were requested for a 10-year period (2012-2021 inclusive). Each report provided sales of each class of antibiotic in total mg and in mg/kg, based on the number of equids treated (for any transaction) and their average weight. The defined daily dose for animals (DDDvet) and the DDD/1000 (used in people) were also calculated to correct for variation in dosage rates between antibiotics.

RESULTS

Fourteen practices submitted data for an annual maximum of 107 977 horses. Overall, median annual antibiotic usage was 54.25 mg/kg (range 45.34-60.27 mg/kg), 1.52 defined daily doses/animal/year (range 1.39-1.70) and 4.17 defined daily dose/1000 animals (range 3.82-4.66). Overall median highest priority critically important antimicrobial usage was 0.67 mg/kg (range 0.56-1.71), 0.12 defined daily doses/animal/year (range 0.10-0.14) and 0.33 defined daily dose/1000 animals (range 0.29-0.39).

MAIN LIMITATIONS

The software relied on the accurate identification of antibiotic preparations. The calculation of DDDvet was complicated by the varying dose rates of antimicrobials used in equine practice.

CONCLUSIONS

A reliable technique to measure antibiotic usage is presented. Defined daily dosage calculations may be more helpful in equine practice due to the preponderance of potentiated sulphonamides usage. These data and methods may provide the basis for future clinical audits aiming to enhance antimicrobial stewardship.

Antimicrobial Prescription Behavior in Equine Asthma Cases: An International Survey

Equine asthma is considered a non-infectious respiratory disease characterized by inflammation and hypersensitivity. Given the importance of antimicrobial stewardship, an international survey was designed to investigate the use of antimicrobials in asthmatic horses and the factors influencing prescription behavior. An online survey was distributed in six languages by international mailing lists and social media from December 2020 to January 2022. Of the 434 responses recorded, 249 veterinarians working in 25 countries finished the survey. These included 79 ECEIM/ACVIM diplomats. A total of 204 respondents confirmed national regulations concerning antimicrobial use in their country. Knowledge of the asthma definitions as presented in the revised ACVIM consensus statement was greater in veterinarians treating over 95% of equine patients compared to veterinarians treating more species, based on 10 questions (answers consistent with the consensus statement in 7 (IQR 5-9) and 4 (IQR 3-6) questions, respectively, (p < 0.001)). A total of 131 respondents stated to use antimicrobials (at least 'sometimes') in at least one of the three presented cases consistent with equine asthma. Trimethoprim-Sulfa combinations, penicillin(s), and tetracyclines were prescribed most (by 105, 53 and 38 veterinarians, respectively). Aminoglycosides, cephalosporins and fluoroquinolones were also selected (22, 15, 9 veterinarians respectively). Tetracyclines and cephalosporins are prescribed more often by veterinarians working without national regulations (p 0.019 and p 0.035, respectively). The most selected factors influencing prescription behavior were: 'tracheal wash culture' (62% of 131 veterinarians using antimicrobials in these cases), 'whether other horses in the barn have similar complaints' (60%), and 'response to other forms of therapy' (53%). In conclusion, insight into prescription behavior is the first step towards minimizing and optimizing antimicrobial use.

Usage of Antimicrobials in Equine Veterinary Practice in Denmark - A Case-Based Survey

Horses may be carriers of important resistant bacteria like methicillin-resistant staphylococci. Such bacteria can potentially threaten both equine and public health, but little is known about predisposing factors like antimicrobial usage patterns in equines. Objectives of this study were to investigate the antimicrobial usage practices by Danish equine practitioners as well as factors impacting usage. A total of 103 equine practitioners filled in an online questionnaire. When asked to explain their typical treatment of six clinical case scenarios, only 1% and 7% of respondents prescribed systemic antimicrobials for a cough and pastern dermatitis, respectively. More frequent usage was reported for diarrhoea (43%), extraction of a cracked tooth (44%), strangles (56%), and superficial wound near a joint (72%). Among the antibiotics indicated for treatment, enrofloxacin was the only critically important antimicrobial agent reported by two respondents. Thirty-eight (36%) respondents worked in practices with antimicrobial protocols. When asked to prioritize the most important factor influencing prescribing habits, bacterial culture (47%) and antimicrobial protocols (45%) were selected far more often than the owner´s economy (5%) and expectations (4%). Veterinarians reported limitations such as the availability of only one oral antibiotic (sulphadiazine/trimethoprim), and a need for clearer treatment guidelines. In conclusion, the study highlighted important aspects regarding antimicrobial usage among equine practitioners. Antimicrobial protocols and pre- and post-graduate education on prudent antimicrobial usage are recommended.