By Mary Hearty

Preventing infections through vaccination is paramount for reducing the need for antibiotics hence combating antimicrobial resistance (AMR) – one of the leading public health threats of the 21st century, according to research by the Lancet on the Global Burden of Bacterial Antimicrobial Resistance.

In 2019, the researchers found that approximately 4.95 million deaths were linked to bacterial AMR with 1.27 million deaths directly caused by drug-resistant bacterial infections globally.

Sub-Saharan Africa reported the highest burden of deaths attributable to and associated with AMR, with Western sub-Saharan Africa recording 27 deaths in every 100,000 samples attributable to AMR and 114 deaths per 100,000 associated with AMR.

The study which was carried out in 204 countries and territories across the globe, obtained data from systematic literature reviews, hospital systems, surveillance systems, and other sources, covering 471 million individual records and 7585 study-location-years.

They analyzed the disease burdens associated with and attributable to AMR for 12 major bacterial infections, 23 bacterial pathogens, 18 drug categories for which there is resistance, and 88 pathogen-drug combinations.

Among the major bacterial infections include: infectious syndromes especially lower respiratory infections and all related infections in the thorax, bloodstream infections, meningitis, typhoid, tuberculosis, infections of the skin, urinary tract infections, diarrhoea, infections of bones, joints, and other related organs, just to mention a few.

According to the findings, of the 12 major infections studied, three infectious syndromes dominated the global burdens attributable to and associated with AMR. These three infectious syndromes include lower respiratory and thorax infections, blood stream infections, and intra-abdominal infections.

Overall, they accounted for 78.8% of deaths attributable to AMR in 2019 with lower respiratory infections accounting for more than 400,000 attributable deaths and 1.5 million deaths associated with AMR.

Out of the 23 pathogens studied, six were associated with the greatest burden of AMR deaths: E coli, Staphylococcus aureus, K pneumoniae, S pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa. In total, they were responsible for 929,000 of 1.27 million deaths attributable to AMR and 3.57 million of 4.95 million deaths associated with AMR.

Pathogens responsible for most of the deaths attributable to AMR were E coli and K pneumonia whereas S pneumoniae, and M tuberculosis had the least.

In terms of regions, E coli and S aureus were responsible for most death attributable to AMR in high-income regions, while K pneumonia and S pneumonia contributed to the highest number of deaths attributable to AMR in sub-Saharan Africa.

In terms of global deaths attributable to bacterial AMR by pathogen-drug combination, the researchers found out that meticillin-resistant S aureus had more than 100,000 deaths.

Resistance to fluoroquinolones and β-lactam antibiotics like carbapenems, cephalosporins, and penicillins—antibiotics often considered first line for empirical therapy of severe infections—accounted for more than 70% of deaths attributable to AMR across pathogens.

Notably, the study highlighted that out of the six leading pathogens contributing to the burden of AMR in 2019 globally; only one pathogen- S pneumonia has been the focus of a major global health intervention program, primarily through pneumococcal vaccination. Although new vaccine programmes are underway for S aureus, E coli, and others

Vaccine development is crucial for pathogens that currently have no vaccine. Other vaccines, such as the influenza or rotavirus vaccines, also play a role in preventing febrile illness, which can lead to a reduction in antibiotic prescribing and can reduce AMR emergence even for pathogens without vaccines.

According to World Health Organization, vaccines can help prevent morbidity and mortality caused by pathogens; and since the clinical presentations of many infections, such as fever, respiratory infection or diarrhoea, do not appreciably differ whether caused by bacteria or viruses, antibiotic use is often empiric.

Overall, the researchers stated that this comprehensive estimate of the burden of bacterial AMR clearly shows that drug resistance in each of these leading pathogens is a major global health threat that needs more attention, funding, capacity building, research and development, and pathogen-specific priority setting from the broader global health community.