Antimicrobial resistance in bacteria isolated from diseased horses in Poland, 2010-2022

The rise of antibiotic resistance is a global health crisis affecting human and veterinary medicine, highlighted within the One Health framework. Horses, classified as both meat and companion animals, play a crucial role in facilitating resistant bacteria spread to humans. Despite increased awareness and reduced antibiotic use in livestock, data on equine antibiotic use and resistance remain limited. This retrospective study examines antimicrobial resistance in 978 bacterial isolates from horses in Poland over 12 years (2010-2022), utilizing data from the Microbiological Diagnostic Laboratory at the Warsaw University of Life Sciences. The most common isolates were Streptococcus spp. (45.60%) and Staphylococcus spp. (19.22%). Clinical isolates resistance pattern observed in this study, particularly to gentamicin, tetracyclines, enrofloxacin, third-generation cephalosporins, and chloramphenicol, strongly suggests the overuse and misuse of these antibiotics, a trend that urgently needs to be addressed to preserve their efficacy. The detection of high-resistance Rhodococcus equi isolates resistant to erythromycin, rifampicin, and doxycycline may pose challenges for foal rhodococcosis treatment soon, especially considering the lack of alternative treatment. The outcomes of this study show the urgent and critical need to collect and analyze local data for improved antimicrobial stewardship. They also emphasize the importance of continuous monitoring of resistance patterns in equine pathogens, as this is crucial for developing effective treatment strategies and staying ahead of potential threats.