• The World Health Organisation (WHO) has released its updated Bacterial Priority Pathogens List (BPPL) 2024.

• It features 15 families of antibiotic-resistant bacteria grouped into critical, high and medium categories for prioritisation. 

• The list provides guidance on the development of new and necessary treatments to stop the spread of antimicrobial resistance (AMR).

• Since the first Bacterial Priority Pathogens List was released in 2017, the threat of antimicrobial resistance has intensified, eroding the efficacy of numerous antibiotics and putting many of the gains of modern medicine at risk.

• By mapping the global burden of drug-resistant bacteria and assessing their impact on public health, this list is key to guiding investment and grappling with the antibiotics pipeline and access crisis. 

15 families of antibiotic resistant (ABR) pathogens

• The 2024 BPPL builds on the 2017 list to address current challenges and provide essential guidance for policymakers, national health authorities and others involved in decisions about R&D and investment. 

• It  includes 15 families of antibiotic resistant (ABR) pathogens, grouped into critical, high and medium categories of priority for R&D and for public health measures.

• The critical priority pathogens, such as gram-negative bacteria resistant to last-resort antibiotics, and Mycobacterium tuberculosis resistant to the antibiotic rifampicin, present major global threats due to their high burden, and ability to resist treatment and spread resistance to other bacteria. 

• Gram-negative bacteria have built-in abilities to find new ways to resist treatment and can pass along genetic material that allows other bacteria to become drug-resistant as well.

• High priority pathogens, such as Salmonella and Shigella, are of particularly high burden in low and middle-income countries, along with Pseudomonas aeruginosa and Staphylococcus aureus, which pose significant challenges in healthcare settings.

• Other high priority pathogens, such as antibiotic-resistant Neisseria gonorrhoeae and Enterococcus faecium, present unique public health challenges, including persistent infections and resistance to multiple antibiotics, necessitating targeted research and public health interventions.

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

The WHO BPPL 2024 includes the following bacteria:

Critical priority:

• Acinetobacter baumannii, carbapenem-resistant

• Enterobacterales, third-generation cephalosporin-resistant 

• Enterobacterales, carbapenem-resistant

• Mycobacterium tuberculosis, rifampicin-resistant.   

High priority:

• Salmonella Typhi, fluoroquinolone-resistant

• Shigella spp., fluoroquinolone-resistant

• Enterococcus faecium, vancomycin-resistant

• Pseudomonas aeruginosa, carbapenem-resistant

• Non-typhoidal Salmonella, fluoroquinolone-resistant

• Neisseria gonorrhoeae, third-generation cephalosporin- and/or fluoroquinolone-resistant

• Staphylococcus aureus, methicillin-resistant.

Medium priority: 

• Group A streptococci, macrolide-resistant

• Streptococcus pneumoniae, macrolide-resistant

• Haemophilus influenzae, ampicillin-resistant

• Group B streptococci, penicillin-resistant.

What is antimicrobial resistance?

• Antimicrobials — including antibiotics, anti-virals, antifungals, and antiparasitics – are medicines used to prevent and treat infectious diseases in humans, animals and plants.

• Antimicrobial Resistance (AMR) occurs when bacteria, viruses, fungi and parasites no longer respond to antimicrobial medicines. 

• As a result of drug resistance, antibiotics and other antimicrobial medicines become ineffective and infections become difficult or impossible to treat, increasing the risk of disease spread, severe illness, disability and death.

• AMR is a natural process that happens over time through genetic changes in pathogens. Its emergence and spread is accelerated by human activity, mainly the misuse and overuse of antimicrobials to treat, prevent or control infections in humans, animals and plants.

• Micro-organisms that develop antimicrobial resistance are sometimes referred to as “superbugs”.

• AMR threatens the very core of modern medicine and the sustainability of an effective, global public health response to the enduring threat from infectious diseases. 

• It is estimated that bacterial AMR was directly responsible for 1.27 million global deaths in 2019 and contributed to 4.95 million deaths.

• In addition to death and disability, AMR has significant economic costs. The World Bank estimates that AMR could result in $1 trillion additional healthcare costs by 2050, and $1 trillion to $3.4 trillion Gross Domestic Product (GDP) losses per year by 2030.

• Antimicrobial resistance is a drain on the global economy with economic losses due to reduced productivity caused by sickness (of both human beings and animals) and higher costs of treatment.

• Systematic misuse and overuse of these drugs in human medicine and food production have put every nation at risk. Few replacement products are in the pipeline. 

• Without harmonised and immediate action on a global scale, the world is heading towards a post-antibiotic era in which common infections could once again kill.

• To counter it needs long-term investment, such as financial and technical support for developing countries and in development of new medicines, diagnostic tools, vaccines and other interventions, and in strengthening health systems to ensure more appropriate use of and access to antimicrobial agents.