Antimicrobial Resistance Responsible for Over Half a Million Deaths in the Americas: Study

Bacterial antimicrobial resistance falls into the WHO’s top 10 threats to humanity. A study reveals how much this deadly problem affects the Americas.

C. diff is a bacterium with a hospitalization rate of about 50 percent and carries a list of symptoms including diarrhea, fever, and stomach tenderness or pain. Kateryna Kon/Shutterstock

Over half a million deaths spanning 35 countries were tied to bacterial antimicrobial resistance (AMR), according to what researchers are calling the most comprehensive AMR burden analysis assessing this particular part of the world. This number has global health officials on edge, considering the growing problem is listed as one of the World Health Organization’s (WHO) top 10 public health threats facing humanity.

The large study, recently published in The Lancet Regional Health–Americas, drew from multiple international sources that provided data from all 35 countries of the WHO Region of the Americas for 23 bacterial pathogens and 88 pathogen-drug combinations.

Deaths Associated With AMR

Analyses revealed bacterial AMR played a role in killing 569,000 people in 2019, representing 11.5 percent of all global AMR-associated deaths. In other words, drug-resistant infections were partly responsible, but there may have been a separate, underlying main cause of death. An additional 141,000 deaths were directly caused by AMR. This number makes up just over 11 percent of all global AMR deaths. 

“Given the burden across different countries, infectious syndromes and pathogen–drug combinations, [bacterial] AMR represents a substantial health threat in the Americas,” the study authors wrote. “Evidence from this study can guide mitigation efforts that are tailored to the needs of each country in the region.”

Lower respiratory infections and thorax, bloodstream, and peritoneal/intra-abdominal infections made up the largest bacterial AMR-associated fatal burden in the region. Fatal burden is a term used to describe the burden of dying prematurely as measured by years of life lost.

Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii were the leading pathogens associated with AMR death. Collectively, these pathogens were responsible for 452,000 of the 569,000 deaths associated with AMR.

Methicillin-resistant S. aureus topped the list in terms of pathogen–drug combination-associated deaths in 34 of 35 countries, and aminopenicillin-resistant E. coli led the combination in 15 of 35.

The Organization of American States (OAS) lists Argentina, Brazil, Columbia, Ecuador, Guatemala, Peru, and the United States as just a few countries that comprise the region.

Regions and Age Groups Most at Risk

Haiti had the lowest proportion of infectious deaths associated with resistant pathogens, while Chile had the highest.

Five countries had incidence rates above 90 deaths per 100,000 person-years. The five ranked from highest to lowest were Haiti, Bolivia, Guatemala, Guyana, and Honduras. Countries with the lowest AMR death rates, defined as fewer than 50 deaths per 100,000 person-years, ranked lowest to highest, were Canada, the United States, Colombia, Cuba, Panama, Costa Rica, Chile, Venezuela, Uruguay, and Jamaica.

According to the study, “Death rates associated with and attributable to AMR followed a generally consistent pattern across countries, with a spike in deaths among neonates followed by near zero rates among 1–4-year-olds.” Trends rising trend increased until people reached 65. After age 65, the upward trend in deaths increased dramatically.

What Are Antimicrobials and Why Do People Become Resistant to Them?

Antimicrobials are medications used to prevent and treat infections and include antibiotics, antivirals, antifungals, and antiparasitics.

Microbes like bacteria, viruses, fungi, and parasites live on and inside creatures and the environment, from animals to people and from the soil to the air, spreading from creature to creature.

Some are harmless and even necessary, while others pose a threat because they continuously evolve due to genetic changes allowing them to replicate and adapt to new environments. AMR occurs when these microbes no longer respond to modern-day medication, making it harder to treat infections. Existing drugs, like antibiotics, may then become ineffective, causing a global risk of disease spread, illness, and death.

The WHO lists the following as the main drivers of AMR:

• Misuse and overuse of antimicrobials.
• Limited access to clean water.
• Poor sanitation and hygiene management in both humans and animals.
• Substandard control of health care facilities and farms.
• Poor access to effective medications, vaccines, and diagnostic procedures.
• Lack of awareness, understanding, and knowledge.

“The WHO Region of the Americas has a long history of surveillance of AMR, but there are still challenges to translate this surveillance into public action,” the authors wrote. “One of these challenges relates to the differentiated nature of the problem for the countries in the region.”

The reasons for AMR-associated deaths and deaths attributable to AMR vary widely by country. Some countries are challenged with access to antibiotics and basic health care services. Others face the largest age-standardized mortality rates linked to and caused by AMR in the region. “For those, the most cost-effective solutions may lie in policies which prevent infections, especially among the age groups that are most affected by infectious diseases,” they wrote.