Imagine a world without antimicrobials. Imagine a world where a common infection like tonsilitis or a simple cut on your finger is life- threatening, or the decision to have a hip replacement could be fatal.
Until the 20th century, bacterial infections we now consider straightforward to treat, such as pneumonia and diarrhoea, were the number one cause of human death in the developed world. Today we rely heavily on antimicrobials to survive. Antimicrobials safeguard us during routine operations, prevent wound infections when we cut ourselves or get bitten, and protect people who are immunosuppressed or receiving chemotherapy. They are also essential to our food chain, protecting animals and vegetation from infection, and enabling agriculture to meet our ever-growing needs. But there is a deadly crisis arising, one that will affect everyone and has the potential to send us back to the healthcare of the early 1900s. This is the rise of antimicrobial resistance – ‘the silent pandemic’.
The World Health Organization (WHO) has declared antimicrobial resistance one of the top ten global public health threats facing humanity. It is estimated that, by 2050, ten million deaths a year will be caused by antimicrobial-resistant infections; roughly the same as the number of people who died from cancer in 2020.
How does antimicrobial resistance occur?
Antimicrobial resistance arises naturally and can either be intrinsic (a trait arising from the biology of the microorganism) or acquired. Acquired resistance occurs when an antibiotic-sensitive bacterium mutates or acquires new genes. Subsequently, horizontal gene transfer between microorganisms enables resistance genes to be passed between different species, facilitating the spread of resistance.
Why are rates of antimicrobial resistance rising?
Major contributing factors to the rise in antimicrobial resistance have been misuse and poor regulation. In many regions, antibiotics are available over the counter with no requirement for prescription. Furthermore, antibiotics are not always taken as directed and courses can be cut short. In these cases, antimicrobial agents are not fully effective and the infecting microorganism has an opportunity to develop resistance. However, human consumption is not the only way we are driving antimicrobial resistance. It is estimated that two-thirds of total antibiotic use occurs in agricultural settings. We use them to increase crop productivity, in animal husbandry and treating/preventing infection, and as growth promoters in animal feed at controlled concentrations. These conditions increase the dissemination of antimicrobial resistance, including multidrug-resistant strains, and contribute to the reservoirs for resistance genes in animals and the environment.
The situation has been exacerbated further by recent events. Since the emergence of COVID-19 there has been an increase in antimicrobial use, with more prescriptions being given prophylactically to prevent secondary bacterial infections in high-risk patients. While the impact of this is not yet fully understood, the increased exposure to antimicrobials in healthcare and community settings is likely to have amplified the opportunity for resistant pathogens to emerge and spread.
There is no doubt we are in desperate need of new treatments, but no new classes of antimicrobials have been identified in decades. The newer and more effective drugs are typically reserved for patients who are critically ill. While this is necessary to preserve efficacy, it does not generate large profits to entice investors and over the past 30 years pharmaceutical companies have decreased efforts towards the development of new antimicrobial therapies.
What can we do?
Thankfully, it is no longer only scientists and doctors who are heeding the warnings around antimicrobial resistance; most policymakers and the public now recognise this global threat. In 2015, countries committed to the WHO global action plan, a multisectoral national action framework that, with correct implementation, will ensure sustainable progress to slow the emergence and spread of resistance. Increased focus is also being placed on finding financial incentives to drive the development of antimicrobials; a subscription-style payment model is being trialled in the UK where pharmaceutical companies receive payment regardless of how often the drug is used. However, as resistance develops at a rate far faster than we can develop new antimicrobials, we still need to do much more. Worldwide antimicrobial stewardship programmes in hospital and community settings are essential to prevent the emergence and transmission of resistant pathogens. Policymakers need to continue to prioritise finding innovative approaches to encourage pharmaceutical companies to invest in developing new therapies.
Finally, we all need to change the way we use antimicrobials and employ healthy infection control habits in our daily lives. Antibiotics should not be requested and must be taken as directed by your doctor. Infection prevention measures such as regular hand washing, keeping cuts clean, getting vaccinated and preparing food safely are all essential too.
We have come a long way since antimicrobials changed the face of healthcare over a century ago, but if we want to preserve the longevity and quality of life we have become accustomed to, we must act now.
