Evaluation of the Bactericidal Effect of Nebulized Silver Nanoparticles on Common Respiratory Bacteria in Horses- In Vitro Studies.
Authors: Frippiat Thibault, Paindaveine Charlotte, Duprez Jean-Noel, Delguste Catherine, Mainil Jacques, Art Tatiana
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Silver Nanoparticles for Equine Respiratory Infections Given rising antimicrobial resistance in veterinary medicine, researchers investigated whether nebulized silver nanoparticles (AgNP) might offer a novel approach to treating bacterial respiratory disease in horses, specifically targeting *Streptococcus equi* subsp. *zooepidemicus* and *Actinobacillus equuli* subsp. *equuli*—two common equine pathogens. The Belgian team used in vitro broth cultures and agar plate assays to measure bacterial susceptibility to AgNP across a range of concentrations (100–2,000 ppm) and delivery methods, with turbidity measurements and growth inhibition assessed at 8 and 24 hours. Both bacteria showed dose-dependent susceptibility, with complete growth inhibition achieved at higher concentrations (500–2,000 ppm) regardless of delivery method, though nebulization of lower concentrations (100 ppm) proved effective against *A. equuli* alone. These findings suggest nebulized AgNP warrants further investigation as a potential therapeutic tool for bacterial respiratory disease, particularly given its demonstrated efficacy at concentrations that may minimise toxicity concerns. However, the translational gap remains substantial: in vivo efficacy, mucosal penetration, and safety profiles in living horses require thorough evaluation before any clinical application could be considered.
Read the full abstract on PubMed
Practical Takeaways
- •Nebulized silver nanoparticles show promise as a potential novel treatment for equine respiratory bacterial infections, potentially addressing antimicrobial resistance concerns
- •Nebulization appears more efficient than direct instillation, suggesting this delivery method may be practical for respiratory therapy in horses
- •Before clinical use, in vivo efficacy and safety/toxicity data are essential as this research is limited to laboratory conditions
Key Findings
- •Both respiratory bacteria were susceptible to silver nanoparticles (AgNP) at all tested concentrations from 100-2,000 ppm
- •Complete growth inhibition was achieved after nebulization of low concentrations (100 ppm) for A. equuli and high concentrations (500-2,000 ppm) for S. zooepidemicus
- •Both bacteria showed progressive susceptibility at increasing dilutions over 24 hours of incubation (up to 1:256 dilution)
- •Nebulized delivery was more effective than instilled AgNP for achieving complete bacterial growth inhibition at lower concentrations