Antibiotic-resistant superbugs have become one of the leading causes of death and are now responsible for more deaths than HIV/AIDS or malaria, according to a new study.

Reported in the Lancet medical journal this week, researchers estimate that antibiotic-resistant bacterial infections directly killed 1.27 million people in 2019 and were involved in the deaths of around 4.95 million people. By comparison, HIV/AIDS and malaria have been estimated to have caused 860,000 and 640,000 deaths, respectively, in 2019

Antibiotic-resistant infections have been on the rise for decades, but these latest findings suggest the threat is creeping up even faster than previously appreciated.

“These new data reveal the true scale of antimicrobial resistance worldwide, and are a clear signal that we must act now to combat the threat. Previous estimates had predicted 10 million annual deaths from antimicrobial resistance by 2050, but we now know for certain that we are already far closer to that figure than we thought. We need to leverage this data to course-correct action and drive innovation if we want to stay ahead in the race against antimicrobial resistance,” Professor Chris Murray, study co-author from the Institute for Health Metrics and Evaluation at the University of Washington, USA, said in a statement.  

Antibiotic resistance is often described as one of the biggest threats to humanity. It occurs when bacteria evolve in a way that prevents the antibiotic from working. When bacteria are exposed to an antibiotic, most will die but some may have picked up mutations that allow them to survive. The surviving bacteria are then able to pass on their resistant features to the next generation, creating colonies of antibiotic-resistant pathogens. Antibiotic resistance can occur naturally, but the overuse and abuse of antibiotic drugs in recent years has been a major driver of the problem. 

For this latest global review, scientists analyzed data on 23 pathogens and 88 pathogen-drug combinations in 204 countries in 2019. Drug resistance in lower respiratory infections had the biggest impact, but drug resistance in bloodstream infections and intra-abdominal infections – commonly caused by appendicitis – also played a major role. 

Deaths caused directly by antibiotic-resistant infections were found to be highest in Sub-Saharan Africa and South Asia, at 24 deaths per 100,000 population and 22 deaths per 100,000 population, respectively. In high-income countries, it directly led to 13 deaths per 100,000 and was linked with 56 deaths per 100,000.  Interestingly, different types of bacteria were causing problems in different parts of the world. In Sub-Saharan Africa, the main killers were drug-resistant S. pneumonia and K. pneumonia, while S. aureus or E. coli were the main issues in higher-income countries. 

This latest study is the first comprehensive analysis of the global impact of antimicrobial resistance and one thing is clear: the world needs to act on this problem urgently. 

"From being an unrecognized and hidden problem, a clearer picture of the burden of AMR [antimicrobial resistance] is finally emerging,” commented Dr Ramanan Laxminarayan from the Center for Disease Dynamics, Economics & Policy in the US, who was not involved in the study.

“Even the lower end of 911,000 deaths estimated by Murray and colleagues is higher than the number of deaths from HIV, which attracts close to US$50 billion each year. However, global spending on addressing AMR is probably much lower than that. This needs to change. Spending needs to be directed to preventing infections in the first place, making sure existing antibiotics are used appropriately and judiciously, and to bringing new antibiotics to market. Health and political leaders at local, national, and international levels need to take seriously the importance of addressing AMR and the challenge of poor access to affordable, effective antibiotics," continued Dr Laxminarayan.