Antimicrobial resistance: the world’s stealthiest killer

Antimicrobial resistance is an ever-evolving threat to global health and development. Stark estimates attributed 4.95 million deaths in 2019 to resistance, with the greatest burden found in sub-Saharan Africa. In light of World Antimicrobial Awareness Week, this article examines the leading causes and impacts of AMR and provides updates on the current strategies in place to tackle this crisis.

Antimicrobial resistance arises when bacteria, viruses, fungi, and parasites change in order to evade treatment with medicines. Whilst the discovery and widespread implementation of antimicrobials remains one of the greatest advancements of the 20th century, they have proven to be a deadly double-edged sword. Resistance arises naturally through mutation; however, the misuse and overuse of antibiotics has created selection pressure which accelerates its emergence.

Mis-prescribing suitable drugs, not completing a course of medication and poor sanitation in healthcare settings provoke the rapid evolution and spread of dangerous pathogens. Further drivers of resistance are found in agriculture and industry; antimicrobials are misused for the growth of animals and plants and contaminate the environment through waste. Research is ongoing to elucidate how resistance festers in the environment and poses threats to human health.

The impacts of antimicrobial resistance are ubiquitous: affecting humans, animals, plants, and the environment. Among these groups, it contributes to the increasing prevalence, economic burden, and mortality of a range of infections. Thus, many pathogens which were previously easily treated can become life threatening.     

The infamous superbug MRSA, methicillin-resistant staphylococcus aureus, is a pathogen whose virulence is largely blamed on antibiotic resistance. Harmless commensal populations reside in many people, only causing mild infection once they enter the body. However, due to the overuse of antibiotics, many of these infections are resistant to an ever-expanding range of antibiotics and can be fatal. Resistance is gained through the acquisition of the gene mecA, which encodes the alternative protein PBP2a, a low-affinity penicillin binding protein. This can catalyse cell wall biosynthesis even in the presence of β-lactam antibiotics, allowing for normal bacterial functioning despite treatment efforts.     

Hospitals are often a prime breeding ground for these germs, as wounds, catheters and feeding tubes provide perfect invasion sites for bacteria. Different strains are spread throughout the hospital via contact; facilitating the birth of deadly varieties which accumulate traits through horizontal gene transfer. 

Scientists are wary of the impact that climate change may have on the spread of antimicrobial resistance. It has been hypothesised that thermal adaptation in microbes may confer resistance to certain antimicrobials, and empirical studies have corroborated the theory that rising temperatures are likely to exacerbate the crisis and impinge on mitigation efforts.

World Antimicrobial Awareness Week, which falls between the 18th-24th of November, is a collaboration between the FAO, UNEP, WHO and WOAH, which aims to educate the public on antimicrobial resistance. Underpinning this strategy is the hope that informed individuals are likely to make better choices around the personal use of antibiotics, and corporations may be encouraged to implement safer practices.

Similarly, the UK government funds a range of programmes, including The Fleming Fund and The Global AMR Innovation Fund. Driven by data sharing, The Fleming Fund informs decision making around the regulation of antimicrobials, health policy and sustainable investment in research in 25 low- and middle-income countries. GAMRIF focuses instead on supporting early-stage research projects in these countries, where the effects of resistance are predicted to be concentrated. In the race against resistance, innovation provides key optimism that we can fight back. For example, scientists have developed antibiotic adjuvants which break resistance in bacteria, through the inhibition of resistance proteins such as DsbA.

It is evident that an intersectoral, One Health approach is key to tackling this vast problem. Pertinent usage of antimicrobials in healthcare and agricultural settings, personal responsibility and continued innovation in medicine must become a priority in order to thwart the silent killer that is antimicrobial resistance.


Image: Elena Mozhvilo on Unsplash

Image: World Antimicrobial Awareness Week logo 2022

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