Nanoparticle-Mediated Interventions for Antimicrobial Resistance in Dairy Farms: A Systematic Review from a One Health Perspective

Introduction: Antimicrobial resistance (AMR) is one of the greatest public health threats, closely linked to the use of antibiotics in industrial animal husbandry, particularly on dairy farms. In recent years, nanotechnology has been proposed as an innovative approach to combat AMR, without additional selective pressure on bacteria. This systematic review aimed to assess the effectiveness of nanoparticle-based interventions in reducing the burden of resistant bacteria and inhibiting the transmission of resistance genes on dairy farms within the One Health framework.

Methods: A systematic search was conducted in PubMed, Scopus, Web of Science, and Science Direct for English-language articles published between January 2015 and December 2024. Original experimental studies that investigated metal nanoparticles (silver, copper, zinc), polymeric nanocarriers, or liposomes for the control of key dairy pathogens (e.g., Escherichia coli, methicillin-resistant Staphylococcus aureus, Mycoplasma bovis) were included. Of the 892 articles found, 47 studies met the inclusion criteria.

Results: Silver nanoparticles (21 studies) and zinc oxide nanoparticles (14 studies) were the most commonly used. In farm studies, intramammary injection of silver–chitosan nanoparticles resulted in a 89% reduction in the number of resistant bacteria in milk and eradication of S. aureus biofilms. However, concerns were raised in several studies about the cytotoxicity of nanoparticles to mammary tissue and their survival in the food chain. Furthermore, studies have shown that nanoparticles can reduce resistance genes in manure, but the environmental disposal of nanoparticles is a new challenge.

Conclusion: Nanoparticle-based interventions have great potential to reduce AMR in dairy farms, but before widespread application, dose standardization, ecotoxicity assessment, and cost-benefit analysis in a unit health framework are essential. The development of biodegradable nanoparticles and their integration into antibiotic stewardship programs is recommended.