What is antimicrobial resistance and how can we tackle it?

This article was first published in March 2023, and updated in August 2023 and November 2023.

In 1928, Alexander Fleming discovered the first antibiotic, penicillin, and by the 1930s, the first antibiotics had become commercially available.

Now, less than a century later, we are facing a health crisis as many drugs that have commonly been used are no longer effective and we struggle to find new treatments to combat infections.

Antimicrobial resistance (AMR) has been described as “one of the biggest threats to global health, food security and development today”. With World AMR Awareness Week 2023 around the corner, we ask: what exactly is it, and why does it pose such a problem?

AMR occurs when microbes – bacteria, fungi, parasites and viruses – evolve to the point where antimicrobial drugs that previously worked against them are no longer effective. As a result of this drug resistance, infections spread and become harder to treat.

Some strains of bacteria have become “superbugs”, developing resistance to multiple forms of treatment. These include MRSA (methicillin-resistant Staphylococcus aureus), Clostridium difficile (C. diff) and the bacteria that cause multi-drug-resistant tuberculosis.

AMR affects all countries, although some are feeling the impact more than others. In particular, Sub-Saharan Africa may bear a particularly heavy burden. However, there is currently a lack of high-quality data on AMR and infectious diseases in low-income areas, researchers say.

We urgently need more innovative, high-quality antimicrobials as resistance spreads and drugs such as antibiotics become less effective.

AMR directly caused 1.27 million deaths globally in 2019 and contributed to an additional 4.95 million deaths. This makes it a bigger killer than HIV/AIDS or malaria. By 2050, this death toll could climb to 10 million deaths annually.

The impacts aren’t limited to health alone, says the World Health Organization (WHO). The global economy will also be affected by higher healthcare costs, reduced productivity and an increase in poverty as a result of antimicrobial resistance. Without action, the WHO warns that it could reduce global GDP by $3.4 trillion and drive an additional 24 million people into extreme poverty.

Natural variations in the genetic makeup of microbes cause resistance to develop over time as they reproduce. For example, alterations in their DNA could mean antimicrobials can no longer reach the microbe cell or make microbes capable of creating enzymes that destroy the antimicrobial. Through natural selection, these microbes with advantageous traits will proliferate over less-resistant strains, spreading the genetic advantage more widely.

Microbes, like bacteria, are also able to directly transfer genetic material to each other in various ways other than reproduction.

Although both of these ways of transferring genetic material occur naturally, poor use of antimicrobials, among other things, can speed up resistance developing and spreading. For example, if an antibiotic course does not totally kill off an infection, we leave behind the microbes best able to fight against the drug. These will then multiply and pass on their survival traits.

Excessive antibiotic use is a significant driver of resistance. If the treatment is too short, weak, or incorrect for the infection, we risk leaving behind resistant microbes. The more we expose microbes to antimicrobials and/or other resistant microbes, the more opportunities we create for resistance to develop and multiply.

And it’s not just prescribing to humans that is a problem – two-thirds of the antibiotics used globally are used in farming. Low-level antibiotics are routinely used for prolonged periods, even in healthy animals, to stave off disease and promote livestock growth. In recent years, antibiotic use in agriculture in Europe has fallen dramatically. But antibiotics continue to be widely used elsewhere, particularly in Brazil, China and other emerging countries, because of their impact on profit margins and a lack of viable and affordable alternatives.

The environment and climate change also have a role to play in the emergence, transmission and spread of antimicrobial resistance, as a recent report from the United Nations highlights. Pollution from healthcare, pharmaceuticals, food and agriculture – such as wastewater from hospitals or agricultural runoff – is particularly problematic, as it may contain both antimicrobials and resistant organisms.

Introducing these to the broader environment will also impact biodiversity and soil health.

Indeed, new research published in The Lancet points to a link between AMR and air pollution. Researchers studied the possible impact of air pollution (PM2.5) on antibiotic resistance in 166 countries, and those with higher levels of air pollution were also found to have higher levels of AMR.

Poor sanitation and access to clean water is another major contributory factor. In countries that lack these basic hygiene measures, water is the primary vector by which antimicrobial resistance and its associated diseases are spread. Improved sanitation, water treatment and basic hand-washing and hygiene facilities are crucial steps in curbing the spread of AMR, as the World Economic Forum points out in a recent paper.

Global coordination is needed to both tackle the rise of antimicrobial resistance as well as foster the development of new drugs. We must also work together to ensure healthcare systems worldwide are prepared for rising resistance and infection levels.

Working with BCG, the Wellcome Trust and the Novo Nordisk Foundation, the Forum has produced a report highlighting how we can promote antibiotic research and development globally. One possible solution is to introduce a subscription payment model to create a regular revenue stream and offset investment costs associated with drug development.

World AMR Awareness Week (WAAW) is an annual global campaign to raise awareness and understanding of AMR. A World Health Organization (WHO) initiative, it aims to promote best practices among the public and policy-makers, who all have a crucial role to play in reducing the emergence and spread of AMR.

Last year's theme of "Preventing antimicrobial resistance together" has been retained for 2023 given the ongoing and increasingly grave threat of AMR to all living creatures on the planet, the WHO says.

WAAW 2023 highlights will include a webinar on Multistakeholder Engagement in the Fight against AMR – Increasing Responsible & Equitable Access to Antimicrobials on 20 November. It will look at how the private and public sectors need to work together on actionable steps to improve access to antimicrobials and diagnostics.

The hopefully titled session Rejuvenating the Global Antibiotic Innovation Ecosystem: The Way Forward, on 21 November, meanwhile, will look at how best to boost reform of the global antibiotic innovation ecosystem.