Evaluation of antimicrobial purchasing by companion animal veterinary facilities in Canada, the United Kingdom, and the United States of America (2019-2021)

Background: Measuring antimicrobial use is a core component of antimicrobial stewardship. Purchasing data may be easier to obtain than prescription data in some situations, but differences in clinic size, caseload and collection timeframes must be considered. Objective: Our objective was to evaluate purchases of systemic antibacterial agents by small animal veterinary facilities in 5 networks across 3 countries, using a mg/veterinarian full time equivalent (FTE)/week as the metric. Methods: Data were obtained from purchasing records of 2194 veterinary facilities from networks from the United States (US, n = 3: US-A, 1036 facilities; US-B, 101 facilities; US-C, 886 facilities), Canada (n = 1: 117 facilities) and the United Kingdom (UK, n = 1: 54 facilities) during 2019-2021. Results: In total, 20 020 269 767 mg (20.02 t) of antimicrobials were purchased. Overall differences between the UK and North America were driven by significantly higher purchases of amoxicillin-clavulanic acid in the UK (P < .001), with substantially less purchasing of third generation cephalosporins in the UK (P < .0001). A significant association was found between FTE and purchasing, with decreased purchasing (mg/FTE/week) as facility FTE increased. Significant differences also were found among US regions. Facilities in the top 10% of total purchasing accounted for 23%-30% of purchases, compared to only 1.6%-3.8% for the bottom 10%. Conclusions and Clinical Importance: These data provide useful information about general purchasing trends, inter- and intraregional differences and differences among facility types and identify high purchasing outliers for further investigation.