Antimicrobial Resistance: Connecting Human, Animal and Environmental Health

Opening Context Antimicrobial resistance is a growing challenge for human and animal health. As disease-causing bacteria and fungi develop resistance to antimicrobial treatments, infections can become increasingly difficult to treat. This challenge extends beyond human healthcare, with resistant pathogens also affecting animals and potentially moving between animals and humans. The One Health approach recognises this interconnected relationship between human, animal and environmental health. This research examines antimicrobial resistance among clinically relevant pathogens, including species identified as priorities by the World Health Organization (WHO), and considers the implications for human and animal health and the food chain. It also explores alternative approaches to controlling harmful microorganisms, including bacteriophages and antimicrobial peptides. This builds on research published in Viruses in 2026 examining bacteriophages as antibacterial agents against bovine pathogens associated with foodborne human illness, supporting the search for effective antimicrobial strategies. Research Overview This research examines antimicrobial resistance in bacterial and fungal pathogens identified by the World Health Organization (WHO) as significant threats to human health. A particular focus is placed on ESKAPE pathogens, a group of bacteria associated with serious infections and increasing resistance to commonly used antimicrobial treatments. Studies have identified clinically important pathogens in companion animals, highlighting the potential for some infections to pass between animals and humans. Laboratory testing is used to determine how these pathogens respond to different antimicrobial treatments and to identify genetic characteristics associated with resistance. This provides evidence on the extent and patterns of antimicrobial resistance among clinically important pathogens associated with animal illness and their potential implications for human and animal health. Key Insights / Findings The findings reveal concerning levels of antimicrobial resistance among clinically important pathogens isolated from companion animals. All ESKAPE bacterial and fungal pathogens investigated displayed multidrug resistance or greater resistance profiles, making infections increasingly difficult to treat. Similarly, all WHO critical- and high-priority bacterial and fungal species tested showed resistance to a broad range of available treatments, with resistance genes also identified. Of particular concern, Escherichia coli (E. coli) displayed extensively drug-resistant (XDR) characteristics, significantly limiting the therapeutic options available for this strain. Together, these findings demonstrate that antimicrobial resistance is not confined to human healthcare settings. Its presence among pathogens associated with animal illness reinforces the close relationship between animal and human health and the importance of monitoring antimicrobial resistance across both. Why It Matters (Impact & Relevance) Antimicrobial resistance is a major global public health challenge, limiting treatment options and making some infections increasingly difficult and costly to treat. Resistant infections can prolong illness, increase healthcare costs and contribute to higher mortality rates. The spread of antimicrobial resistance through the environment and between different pathogens further increases the potential risks to human and animal health. Addressing this challenge requires a coordinated approach that combines improved surveillance, rapid diagnostics, responsible use of antimicrobial treatments and effective prevention strategies. Identifying resistance patterns in disease-causing pathogens can help healthcare and veterinary professionals select the most appropriate treatments while avoiding unnecessary or ineffective antimicrobial use. This research therefore contributes to wider efforts to strengthen antimicrobial stewardship and preserve the effectiveness of existing treatments for both human and animal health. Wider Context / Application / Next Steps Future research will explore the relationship between antimicrobial-resistant pathogens that can pass between animals and humans and the potential risk of severe infections such as sepsis. This is particularly important as antimicrobial resistance can make infections more difficult to treat and further limit therapeutic options for vulnerable patients. Alongside this work, the research has wider practical applications in preventing and controlling harmful microorganisms across a range of settings. This builds on a wider body of research into pathogenic drug-resistant fungi and approaches to their control, including research published in the International Journal of Molecular Sciences in 2023 and the Journal of Applied Microbiology in 2025. Findings can inform approaches to biocontrol, sterilisation and disinfection in hospitals and other clinical environments, production facilities and food-production settings, including livestock housing. The research can also contribute to the development of effective sterilisation protocols for medical devices.