Abstract
Introduction: A multicenter description and comparison of antimicrobial treatment approaches for acute diarrhea in horses is missing. This study aimed to describe and compare the treatment approaches for diarrheic horses used in different regions of the world.
Study Design: Multicenter retrospective study.
Methods: Information from diarrheic horses presented to participating institutions between 2016 and 2020, including clinicopathological data, pathogens detected, and antimicrobial drug use, was collected.
Results: This study included 1438 horses and 26 referral institutions across 5 continents (North and South America, Europe, Australia, and Asia). The fatality rate was 24%, with no differences between regions. A pathogen was identified in 16% of the horses. 55% (792/1419) of the horses were administered one or a combination of antimicrobial drugs within the first 24 hours of admission. Penicillin and gentamicin were the most used combination (25%, 198/792). The proportion of horses treated with antimicrobial drugs differed among institutions, varying from 17% to 94%. The proportion of horses treated with antimicrobial drugs was lower in Europe and Australia than in the other geographic areas (P < .05). In total, 540/1139 (47%) horses had leukopenia, and 70% (380/540) of those horses were administered antimicrobial drugs, while 49% (293/599) of the horses without leukopenia received antimicrobial drugs. 66% (794/1105) of the horses met SIRS criteria, and 28% (311/1105) did not. Of those, 68% (542/794) and 44% (136/311) of the horses that did and did not me SIRS criteria, respectively, were administered antimicrobial drugs.
Discussion: Treatments varied between regions and hospitals. Prospective clinical trials are required to evaluate the effects of antimicrobial treatment on survival.
Clinical relevance: The high prevalence of antimicrobial use in diarrheic horses, even without evidence of systemic compromise, indicates that factors other than disease severity influence clinicians' decisions to administer antimicrobial drugs to diarrheic horses.