Pattern of prescriptions and prudent use of antimicrobial in horse practice at a Veterinary Teaching Hospital

Antimicrobial prescriptions of the University of Pisa and their compliance with prudent use recommendations were investigated over 11 years (2011-2021). At least one antimicrobial was always prescribed in surgical prophylaxis for the suture of wounds and in 33% of horses with signs of disease of a body system. Antimicrobials were administered in monotherapy (48%) in fixed dose combinations (21%) and empirical combinations (31%). Antimicrobials were mostly (63%) administered by parenteral route, while oral and topical antimicrobials accounted for 14% and 23% of prescriptions, respectively. Gentamicin, benzylpenicillin and ceftiofur were the most prescribed antimicrobials; aminoglycosides, penicillins and cephalosporins were the most common class of antimicrobial prescribed. Protected antimicrobials (WHO HPCIA and rifampicin) represented 24% of antimicrobial dispensations. The pattern of classes of antimicrobial used by body system was broad and included up to eight different pharmaceutical classes. The heterogeneity of antimicrobial use was confirmed by the estimate of the prescription diversity index. Antimicrobial prescriptions were in compliance with prudent use recommendations in terms of availability of diagnosis, respect of the dose range and duration of treatment On the contrary, principles of appropriate antimicrobial use have only been partially observed in relation to off-label use, use of antimicrobials in empirical combination, use of antimicrobial susceptibility tests and use of protected antimicrobials, suggesting that additional interventions are required to improve the responsible use of antimicrobials use in our equine practice.