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Drug-resistant bacteria killed almost 1.3 million people in 2019, scientists have estimated — more than either HIV or malaria.
Researchers also estimated that antibiotic-resistant bacterial infections played some role in 4.95 million deaths in the same year.
The findings of the study — which was funded by the U.K. government and the Bill & Melinda Gates Foundation — were published in the peer-reviewed medical journal The Lancet on Wednesday.
The World Health Organization has described antibiotic resistance as “one of the biggest threats to global health, food security, and development today,” and said that although the phenomenon occurs naturally, misuse of antibiotics in humans and animals is accelerating the process.
Antibiotics are sometimes needed to treat or prevent bacterial infections. But the overuse and misuse of antibiotics — such as in the treatment of viral infections like colds, which they are not effective against— has helped some bacteria evolve to become resistant to them.
This resistance is threatening our ability to treat common illnesses, leading to higher medical costs, longer hospital stays and increased mortality. According to the U.S. Centers for Disease Control and Prevention, more than 2.8 million antibiotic-resistant infections occur in the United States each year, with more than 35,000 people dying as a result.
A growing number of illnesses, including pneumonia, tuberculosis and gonorrhea, are becoming more difficult to treat as antibiotics are becoming a less effective tool against the bacteria that cause them.
Authors of the research paper describe bacterial antimicrobial resistance (AMR) as “one of the leading public health threats of the 21st century,” adding that their study presented the first global estimates of the burden it was adding to populations worldwide.
The study looked at 471 million individual records from 204 countries and territories, and analyzed data from existing studies, hospitals and other sources. Its estimates were based on the number of deaths arising from and associated with bacterial AMR for 23 pathogens (organisms that cause disease) and 88 pathogen-drug combinations.
Lower respiratory infections like pneumonia, which were responsible for 400,000 deaths, were the “most burdensome infectious syndrome” relating to bacterial AMR, researchers said. Bloodstream infections and intra-abdominal infections were the next most prevalent drug-resistant diseases that led to deaths in 2019. Combined, these three syndromes accounted for almost 80% of deaths attributable to AMR.
E. coli and MRSA (methicillin-resistant staphylococcus aureus) were among the drug resistant bacteria that led to the most deaths, the study found. So-called “superbug” MRSA directly accounted for more than 100,000 deaths during the analysis period, researchers found.
The six pathogens identified in the study as causing the most deaths from AMR have been identified by the WHO as priority pathogens, researchers said.
Globally, 16.4 deaths in every 100,000 were attributable to drug resistant bacteria in 2019, according to the study. In western sub-Saharan Africa, where AMR accounted for the highest proportion of deaths in the world, that rate rose to 27.3 per 100,000 deaths.
Meanwhile, deaths associated with, but not directly caused by, bacterial AMR accounted for 64 in every 100,000 deaths in 2019, researchers said.
“Our findings clearly show that drug resistance in each of these leading pathogens is a major global health threat that warrants more attention, funding, capacity building, research and development, and pathogen-specific priority setting from the broader global health community,” the scientists said in their paper.
The study’s authors called for stringent intervention strategies, many of which were linked to antibiotic use, to address the threat posed by drug resistant bacteria. Suggestions made in the paper included reducing human exposure to antibiotics in meat, minimizing the unnecessary use of antibiotics — for example, in treating viral infections — and preventing the need for antibiotics through vaccination programs and vaccine development.
Researchers also said it was “essential” to maintain investment in the development of new antibiotics.
“In the past few decades, investments have been small compared with those in other public health issues with similar or less impact,” they said.
The study’s authors acknowledged that their research had some limitations, including sparsity of data from low- and middle-income countries, which could lead to an underestimation of the AMR burden in certain regions.
“Efforts to build laboratory infrastructure are paramount to addressing the large and universal burden of AMR, by improving the management of individual patients and the quality of data in local and global surveillance,” the report’s authors said.
“Enhanced infrastructure would also expand AMR research in the future to evaluate the indirect effects of AMR … Identifying strategies that can work to reduce the burden of bacterial AMR is an urgent priority.”