Antimicrobial strategy for respiratory disease

Knowledgeable use of antimicrobials in horses is essential in the antimicrobial-resistant world in which we live and work. We all know the gold standard, but what should we do when we need empirical treatment, if we can’t perform culture and sensitivity for practical and/or economic reasons?!

Firstly, we need to know our region. This means that we require contemporary data of local pathogens and their antimicrobial sensitivity patterns (aka antibiograms).

Secondly, we need to know that just because a client thinks we should provide antimicrobials in a febrile horse, we know we shouldn’t if it is likely a viral infection &/or the horse is improving. At least, we can decide to watch for 12-48 hours and reassess the patient. Thirdly, we must recognise the likelihood of a certain bacterial species causing certain clinical signs in the horse. Fourthly, we use our knowledge of what antimicrobials are empirically helpful against distinct bacterial pathogens in choosing an antimicrobial. Finally, we need to be ready to firmly advocate for our patients [and indeed humanity (through us not being responsible for the exacerbation of antimicrobial resistance)] and perform culture and sensitivity on samples including nasal swabs, guttural pouch lavage, tracheal lavage fluid and pleural fluid. Remember that if you have diagnosed pleuropneumonia through ultrasonographic examination, then after pleurocentesis, we need to collect and submit pleural fluid samples for both aerobic and anaerobic culture.

Dr CJ (Kate) Savage BVSc(Hons), MS, PhD, Diplomate ACVIM has enjoyed a wonderful career in equine internal medicine. Kate is now a board member of the Victorian Racing Integrity Board (VRIB) in Australia. Her interests include cardiology and respiratory medicine in horses, and the advancement of welfare and health in horses, including those in competition.