In vitro susceptibility of Borrelia burgdorferi isolates to three antibiotics commonly used for treating equine Lyme disease.
Authors: Caol Sanjie, Divers Thomas, Crisman Mark, Chang Yung-Fu
Journal: BMC veterinary research
Summary
# Editorial Summary: Antibiotic Susceptibility in Equine Lyme Disease Borrelia burgdorferi susceptibility to commonly prescribed equine antibiotics remained largely uncharacterised, prompting Sanjie and colleagues to evaluate three isolates of this spirochaete against three antibiotic classes routinely used in equine practice. Using in vitro susceptibility testing, the researchers determined minimum inhibitory concentrations (MIC) for tetracyclines, macrolides and beta-lactams—drugs selected because they offer practical advantages over intravenous regimens, including oral bioavailability and reduced treatment burden in a species requiring prolonged antimicrobial courses. Whilst specific MIC values warrant examination of the full paper, this work establishes a baseline for understanding how effectively our current oral and parenteral treatment options inhibit B. burgdorferi growth in controlled laboratory conditions. For practitioners managing equine Lyme disease, these findings provide evidence to support antibiotic selection and may highlight scenarios where treatment efficacy could be compromised, though clinical outcomes do not always correlate perfectly with in vitro susceptibility data. The data becomes particularly relevant as resistance patterns emerge and clinicians seek to optimise protocols that balance therapeutic efficacy with practical delivery constraints inherent to treating horses over extended periods.
Read the full abstract on PubMed
Practical Takeaways
- •This research provides in vitro data to help guide antibiotic selection for oral treatment of equine Lyme disease, addressing the challenge of long-term injectable therapy
- •Understanding MIC values for different antibiotics can help practitioners select agents with optimal bioavailability and tolerability for individual horses
- •Results support development of effective oral treatment protocols that are more practical for field management of Lyme disease in horses
Key Findings
- •Three B. burgdorferi isolates were tested for susceptibility to tetracycline, macrolides, and beta-lactam antibiotics commonly used in equine practice
- •Study determined minimum inhibitory concentrations (MIC) for antibiotics to inform oral treatment options for horses with Lyme disease
- •In vitro testing evaluated drugs with potentially better bioavailability and lower side effect profiles compared to IV/IM alternatives