Infection control and antimicrobial resistance

Many organisms live in and on our bodies. They are normally harmless and are even helpful, but under certain conditions, some organisms may cause sickness and disease. Some of these infectious diseases can be passed from human to human, and human to animal and vice versa. Some bacteria are becoming resistant to our developed antibiotics – the treatment originally developed to fight them.

For some of these bacteria, antibiotics are the only cure we have to fight them.

Antimicrobial resistance (AMR) occurs when bacteria, viruses, fungi, or parasites change over time and stop responding to the medicines designed to kill them. When this happens, infections become harder to treat, and the medicines we rely on — antibiotics, antivirals, antifungals, and antiparasitics — no longer work effectively.

AMR is a biological phenomenon that brings one of the greatest threats to modern medicine – both human and animal.  For humans, it is estimated that bacterial AMR caused 1.27 million global deaths in 2019 and contributed to a further 4.95 million deaths⁽¹⁾. There is no accurate record of the number of animal deaths resulting from AMR ^{(2, 3)} but gross domestic product (GDP) loss due to AMR in livestock is predicted to be US$ 575 billion by 2050 ⁽⁴⁾.

Fortunately, research and awareness around AMR have resulted in major scientific, clinical, and policy advances around both the benefits and challenges of AMR.

Benefits of Understanding and Researching AMR

1. Better scientific understanding: Studying how microbes become resistant has advanced knowledge in microbiology, genetics, and drug discovery.
2. Encourages innovation: The challenge of AMR drives the search for new antibiotics, vaccines, and alternative treatments (e.g. bacteriophage therapy).
3. Promotes responsible antibiotic use: Raising awareness helps to reduce the misuse of antimicrobials in both humans and animals.
4. Supports global cooperation: AMR has united human, veterinary, and public health experts worldwide through data sharing and surveillance networks (for example, the WHO’s GLASS initiative⁽⁵⁾).

Challenges of AMR

1. Treatment failures and deaths: Infections can become untreatable because the microbes are resistant to the medicines, leading to more illness and deaths in both humans and animals. Some strong antibiotics are reserved only for human use ^{(6, 7)}, limiting options for vets.
2. Economic impact: Resistant infections lead to longer hospital stays, higher medication/ treatment costs, and lost productivity ⁽⁸⁾. In low-income countries and veterinary medicine, expensive treatments may be unaffordable for the humans and animal guardians that need them.
3. Threat to modern healthcare: Without effective antimicrobials, surgeries, cancer treatments, and transplants are much higher risk ⁽⁹⁾.
4. Slow development of new drugs: Pharmaceutical companies are often reluctant to invest in new antimicrobial medicines due to low financial returns ^{(10, 11)}.
5. Global inequality: Low-income countries face greater AMR risks due to weaker regulations, poor sanitation, and limited access to diagnostics and medicines ⁽¹²⁾.

One Medicine and One AMR

One Medicine is the idea that human and veterinary medicine share a common scientific foundation. It encourages doctors and veterinarians to work together, share research, and learn from each other to improve treatments for both people and animals.

This concept came before One Health and focuses mainly on biomedical and clinical similarities, not on environmental or ecological aspects.

How AMR Fits into the One Medicine Concept

AMR is a prime example of how human and animal medicine are connected. Microbes evolve and spread resistance using the same biological mechanisms in both humans and animals. Because of this, both fields face similar challenges — and both can benefit from shared medical research and collaboration.

Key Links Between AMR and One Medicine

• Shared resistance mechanisms: The same resistance genes and processes (such as β-lactamase production or gene transfer) occur in both human and animal bacteria.
  Example: Extended-spectrum β-lactamase (ESBL) resistance was identified in both human and veterinary E. coli, improving understanding of treatment failures in both ⁽¹³⁾.
• Comparative pharmacology and responsible use: Studying how antibiotics work in different species helps identify proper doses and prevent misuse.
  Example: Research on antibiotic use in food animals has informed better prescribing practices for people ⁽¹⁴⁾.
• Cross-species clinical research: Many antibiotics are tested in animals before being used in humans. However, studying naturally occurring resistant infections in animals may predict how resistance might behave in human patients ⁽¹⁵⁾.
• Shared diagnostics and surveillance: Human and veterinary laboratories can share data on resistant strains, helping to both detect new threats and improve treatment strategies ⁽¹⁶⁾.
• Drug development and repurposing: Medicines can sometimes be adapted from one species to another.
  Example: anticancer drugs have been found to be effective against fluoroquinolone-resistant microbial pathogens and antibiotic-resistant Staphylococcus aureus ⁽¹⁷⁾.

In Summary

AMR sits at the heart of the One Medicine approach because it shows how human and animal health are biologically intertwined. Resistance evolves the same way in all species, so solutions must come from shared science, shared responsibility, and shared innovation.

In other words, AMR within the One Medicine framework is a joint clinical and biomedical challenge — best addressed through collaboration between doctors and vets, not through environmental or public policy measures (as in One Health).