WHO updates list of priority bacterial pathogens to combat antibiotic resistance

The World Health Organization (WHO) has released an updated list of its priority bacterial pathogens (BPPL) for 2024, including 15 families of antibiotic-resistant bacteria. These bacteria are grouped into critical, high and medium categories for priority attention. The list provides recommendations for developing needed new treatments to stop the spread of antimicrobial resistance (AMR).

AMP occurs when bacteria, viruses, fungi and parasites no longer respond to medications, making people sicker and increasing the risk of disease spread, morbidity and mortality. The main causes of AMR are misuse and overuse of antimicrobials. The updated BPPL includes new data and expert opinion to guide research and development (R&D) of new antibiotics and stimulate international coordination to promote innovation.

“Mapping the global burden of drug-resistant bacteria and assessing their impact on public health are key to guiding investment and combating the antibiotic crisis and access to antibiotics,” says Dr Yukiko Nakagani, WHO interim Deputy Director-General for antimicrobial resistance.

Critical priority pathogens

Critical priority pathogens, such as gram-negative bacteria resistant to last-line antibiotics and Mycobacterium tuberculosis resistant to rifampicin, pose serious global threats due to their high burden and ability to resist treatment and spread resistance to other bacteria. Gram-negative bacteria have built-in mechanisms for finding new ways to resist treatment and can transfer genetic material to other bacteria, allowing them to become resistant to drugs.

High priority pathogens

High priority pathogens such as Salmonella and Shigella have a particularly high burden in low- and middle-income countries, as well as Pseudomonas aeruginosa and Staphylococcus aureus, which pose significant problems in health care settings.

Other high priority pathogens, such as antibiotic-resistant Neisseria gonorrhoeae and Enterococcus faecium, present unique public health challenges, including persistent infections and multi-antibiotic resistance, which require targeted public health research and interventions.

Medium priority pathogens

Medium priority pathogens include Streptococcus groups A and B (both new to the 2024 list), Streptococcus pneumoniae, and Haemophilus influenzae, which represent a high disease burden. These pathogens require increased attention, especially among vulnerable populations, including children and the elderly, especially in resource-limited settings.

“Antimicrobial resistance threatens our ability to effectively treat the high burden of infections such as tuberculosis, leading to severe morbidity and increased mortality,” says Dr Jérôme Salomon, WHO Deputy Director-General for Universal Health Coverage and Infectious Diseases. Non-communicable diseases.

Changes in the 2017 and 2024 lists

BPPL 2024 includes the removal of five pathogen-antibiotic combinations from the 2017 list and the addition of four new combinations. The fact that Enterobacterales resistant to third-generation cephalosporins are included as a separate item in a critical priority category highlights their burden and the need for targeted interventions, especially in low- and middle-income countries.

The movement of carbapenem-resistant Pseudomonas aeruginosa (CRPA) from critical to high category in BPPL 2024 reflects recent reports of declining global resistance. Despite this change, investment in R&D and other prevention and control strategies for CRPA remains important given its significant burden in some regions.

WHO BPPL 2024 includes the following bacteria:

Critical priority:

• Acinetobacter baumannii, resistant to carbapenems;
• Enterobacterales resistant to third generation cephalosporins;
• Enterobacterales resistant to carbapenems;
• Mycobacterium tuberculosis resistant to rifampicin (included after independent analysis using an adapted multi-criteria decision matrix).

High priority:

• Salmonella Typhi, resistant to fluoroquinolones;
• Shigella spp., resistant to fluoroquinolones;
• Enterococcus faecium, resistant to vancomycin;
• Pseudomonas aeruginosa, resistant to carbapenems;
• Nontyphoidal Salmonella, resistant to fluoroquinolones;
• Neisseria gonorrhoeae, resistant to third generation cephalosporins and/or fluoroquinolones;
• Staphylococcus aureus, methicillin-resistant.

Medium priority:

• Group A Streptococcus, macrolide-resistant;
• Streptococcus pneumoniae, resistant to macrolides;
• Haemophilus influenzae, resistant to ampicillin;
• Group B Streptococcus, resistant to penicillin.

Changes since 2017 reflect the dynamic nature of MDA, requiring tailored interventions. Using BPPL as a global tool while taking into account regional contexts can account for variations in pathogen distribution and AMR burden. For example, antibiotic-resistant Mycoplasma genitalium, which is not listed, is a growing problem in some parts of the world.