Removing cost barriers may increase feline culture rates but has limited impact on antibiogram representativeness

Veterinary medicine is integral to the response to the global health crisis of antimicrobial resistance (AMR). Livestock and companion animals frequently harbor and potentially transmit resistant bacteria to humans, yet sometimes veterinarians prescribe antimicrobials to animals without confirming bacterial infection with culture and susceptibility testing. Lack of culture sample submission also limits the ability of diagnostic laboratories to create informative, unbiased antibiograms, also called cumulative susceptibility reports, impairing decision-making for empirical antimicrobial drug prescribing. We hypothesized that the cost of cultures, which are borne by animal owners, is the primary barrier to culture and susceptibility testing in companion animal practice. This study evaluated the impact of a subsidized diagnostic testing program at a veterinary medical teaching hospital on antibiogram reports and testing proportions. The subsidy was implemented in two phases: an initial 16-month period requiring clinicians to complete a form to access free testing, followed by a 2-month period with automatic application of the subsidy without forms. Significant changes in susceptibility (pre vs post subsidy) were observed for several organism-drug combinations, including decreased fluoroquinolone susceptibility in Streptococcus canis and improved beta-lactam susceptibility in Staphylococcus pseudintermedius . Culture submission proportions showed mixed results: canine submissions significantly decreased during the form-required period but showed no change during the automatic subsidy period, while feline submissions showed no significant changes in either period, though there was a non-significant trend toward increased submissions during the automatic subsidy period. This initiative highlights both the complexity of implementing diagnostic subsidies in veterinary practice and the potential for improving the representativeness and utility of diagnostic antimicrobial susceptibility testing (AST) data, which may support broader AMR monitoring efforts when appropriately analyzed.