Antimicrobial resistance

Antimicrobial resistance (AMR) happens when antimicrobial medicines are no longer effective in killing or slowing the growth of microorganisms that cause disease. This makes infections harder to treat and increases the risk that diseases will spread.

Antimicrobial medicines include antibiotics, antivirals, antifungals and antiparasitics. AMR affects all four categories of antimicrobials.

Bacteria, viruses, fungi or parasites that have developed this kind of resistance are sometimes called ‘superbugs’. Strains of bacteria that have developed resistance to antibiotics include methicillin-resistant Staphylococcus aureus (MRSA) and Clostridioides difficile (C diff).

AMR has been described as a ‘catastrophic threat’ to human and animal health. Bacterial AMR was linked to an estimated 4.95 million deaths and was directly responsible for 1.27 million deaths worldwide in 2019. Researchers have estimated that this figure could increase to 1.91 million by 2050.

Causes and consequences of AMR

The development and spread of AMR are accelerated by the inappropriate use of medicines (for example, prescribing antibiotics to treat a viral infection), use of low-quality medicines and poor infection control. The widespread use of antimicrobials in agriculture has also been implicated, and accumulating evidence suggests that resistance that develops in farmed animals or in the natural environment can spread to humans.

AMR reduces our ability to treat common infectious diseases, resulting in prolonged illnesses, more complications and disability, and an increased risk of disease spread. AMR also compromises advances in modern medicine that rely on effective antimicrobials, such as organ transplantation, chemotherapy, and major surgery.

Besides humans, AMR affects animal health and the wider environment, and has implications for food security, environmental wellbeing and socio-economic development. In March 2017, the World Bank Group estimated that the effects of AMR could reduce annual global gross domestic product by between 1.1% and 3.8% by 2050. 

UK action and progress on AMR

UK policy on AMR is informed by a ‘one health’ approach, which recognises the interconnectedness of human, animal and environmental health. There are three key aspects to AMR policy: reducing rates of infection (and hence the need to use antimicrobial medicines), ensuring that antimicrobials are used appropriately when they are needed, and supporting the development and supply of new diagnostic tools, vaccines and treatments.

The UK-wide 20-year vision for antimicrobial resistance sets out the government’s plans to contain and control AMR by 2040. This document is backed up by the five-year national action plan, Confronting antimicrobial resistance 2024 to 2029, setting out commitments and targets to reduce the inappropriate use of antimicrobials and numbers of drug-resistant infections. The UK plan is informed by the World Health Organization’s global action plan on AMR.

The 2024 to 2029 national action plan sets out specific targets, including:

• preventing any increase in the numbers of certain drug-resistant infections in humans (compared with a 2019 to 2020 financial year baseline)
• increasing UK public and healthcare professionals’ knowledge on AMR by 10% (compared with 2018 and 2019 baselines respectively)
• reducing total antibiotic use in humans by 5% (compared with 2019).

In March 2024, the government stated that the majority of commitments in the previous 2019 to 2024 national action plan have been assessed as completed or on track for delivery. The latest data shows that by 2022, the use of antibiotics in food-producing animals had fallen by 59% since 2014, and the use of antibiotics in humans had fallen by 8.8%.

There was a drop in the use of antibiotic medicines at the start of the Covid-19 pandemic, but the latest government data shows an increase in numbers of drug-resistant infections and antibiotic use in 2022.

Less progress has been made on reducing the number of drug-resistant infections. Data for England shows only a 1.6% reduction in the number of these infections between 2018 and 2022.

Other new initiatives include pilots of a new ‘one health’ surveillance system and a subscription-style payment model for antimicrobial medicines.

• The PATH-SAFE research programme aims to track drug resistant microorganisms in the agricultural and food systems throughout the UK.
• The Antimicrobial Products Subscription Model aims to incentivise pharmaceutical companies to develop new medicines and discourage overuse, by paying drug manufacturers a fixed annual fee for access to antimicrobial medicines.