Tackling antimicrobial resistance in dairy production: smartphone microfluidics for parallel resistance gene detection alongside functional antibiotic

Antimicrobial resistance (AMR) in bacteria is a major threat to human and animal health, and to food production/security. Antimicrobial use in food animals contributes to the emergence and spread of antimicrobial resistant bacteria (ARB), which can spread from animals to humans via various pathways, including contaminated milk and dairy products entering the human food chain. Additional data regarding the potential exposure of British consumers to AMR in milk and other dairy products (e.g. raw milk cheeses) and assessment of associated health risk is vital. However, scientific evidence and surveillance data regarding AMR in milk and dairy products in the UK remains limited, confirmed in a 2016 Food Standards Agency report. This project aims to develop miniaturised, next-generation tools for the detection and analysis of AMR, exploiting smartphone and microfluidic technology, to provide new data for understanding and controlling this public health risk. In our recent small-scale feasibility study of milk samples, we found examples of antibiotic resistant bacteria, both pathogenic and non-pathogenic species (i.e. commensals/healthy milk microbiota). Furthermore, some bacteria were resistant to multiple antibiotics (>3 different classes) including 'Highest Priority Critically Important' antibiotics. We found these in milk from both healthy cows and suffering from mastitis. The presence of ARB carrying AMR genes raises concerns about the safety of raw milk as well as cheese made from raw milk. ARB causing mastitis infection also makes it challenging to maintain animal health and welfare, because treating mastitis (and indeed other infections) becomes more challenging and treatment failure more common. Current AMR detection methods remain far too slow (>2d) and laborious for both surveillance, and for AMR detection to guide antibiotic selection when treating mastitis, requiring expert technicians in centralised labs. Microfluidics can perform rapid tests and when combined with the latest smartphone and digital imaging technology, these laboratory techniques can be transported into the field. We will develop cutting-edge rapid and portable technology for parallel detection of both AMR genes, and of functional antibiotic susceptibility. These will be developed specifically for addressing AMR challenges in dairy production, contributing to food security by allowing us to understand and prevent AMR arising in milk and cheese production and spreading to humans.