Analyzing the WHO’s 2024 Priority Pathogens: Successes and Omissions
Year: 2025
Type: article
Abstract: The World Health Organization (WHO) has recently published a list titled “Bacterial Priority Pathogen List” organisms that are of concern to public health.[1] This is the second such list after 2017 when they came up with the first list. We are here to throw a light and to apprise the readers of the key changes in the list. These are basically lists of bacteria of importance for public health and to guide for research, development, and strategies to prevent and control antimicrobial research. This 2024 list is prepared from the older list to address concerns with current issues and trends though it needs with the future aspects of upcoming changes in the world. It also takes care of the changes in antimicrobial resistance (AMR) patterns after COVID-19. The current list has 15 groups of pathogens and has simply been categorized into critical, high, and medium groups given in Table 1.[1,2] AMR guidelines should be updated regularly as worldwide drug resistance is increasing among bacterial agents. With this perception, the WHO updated the priority pathogen list where they have included some multidrug-resistant (MDR) organisms in the list.Table 1: Categorywise distribution of organisms in the World Health Organization bacterial priority pathogens' listPathogens that were part of the 2017 list but removed in the 2024 list are 3rd generation cephalosporin resistant Providencia species; Clarithromycin-resistant Helicobacter pylori; Fluoroquinolone-resistant Campylobacter species; Vancomycin Intermediate and Vancomycin Resistant Staphylococcus aureus; and Penicillin non-susceptible Streptococcus pneumoniae.[1,2] According to the WHO, critical group pathogens, which are antibiotic-resistant bacteria, pose a high risk to public health because they have limited treatment options. They also can cause high morbidity and mortality, are very difficult to prevent, have high transmissibility, and have limited antibiotics in development. High-priority groups of bacterial agents causing infections are relatively easier to treat and have less of causing morbidity and mortality compared to critical group bacterial agents. Along with that, they have some newer agents in the pipeline for them. The medium category has pathogens that are moderate to treat and cause fewer problems than the above two.[1] Another change we could gauge is the rise in prominence of carbapenem-resistant Klebsiella pneumoniae followed by 3rd-generation cephalosporin-resistant Escherichia coli and the downgrading of carbapenem-resistant Acinetobacter baumannii as compared to 2017.[1,2] Category upgradation of several organisms in newer list depended on the reports/data/prevalence of the MDR pathogens in the last few years globally. Majority of the hospitals are using higher antibiotics like 3rd generation cephalosporins and carbapenems as a part of empirical therapy leading us towards increasing trends of drug resistance. As per the new list, available treatment for carbapenem-resistant Gram-negative bacilli (GNB) is only polymyxins (including colistin) though resistance against colistin is also reported in various parts of the world. As per the study conducted by Torres et al. to check the colistin susceptibility by five different assays, 31.95% (31 of 97 tested isolates) were reported resistant to colistin.[3] Colistin is considered a life-saving drug for Carbapenem-resistant GNB, which used longer time in patient treatment. K. pneumoniae, Pseudomonas aeruginosa, and A. baumannii are the most notorious for developing multidrug resistance mechanisms. Several strains of those organisms are reported pan drug resistant to all available antibiotics including polymyxins and tigecycline.[4-8] The WHO modified the priority pathogen list after 7 years of the first list, but still there is scope for improvements. There may be two probable reasons behind the very little literature available on colistin-resistant GNB data: 1) Very few centers have facilities available for colistin susceptibility testing in routine practice, and 2) the prevalence of colistin resistance is lower than 3rd generation cephalosporin resistant and carbapenem-resistant GNB.[8-10] The reason behind writing this update is to apprise the readers of the constant threat the drug-resistant microbes are playing and how the threat perception has changed post-2017, especially after the COVID-19 pandemic. In summary, the carbapenem and 3rd-generation cephalosporin-resistant GNB are the most critical organisms and rifampicin-resistant tuberculosis is also prominent due to various factors. However, in the near future, the WHO can include other drug-resistant GNB in their upcoming updated list after few years. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Language: English
Subfield: Applied Microbiology and Biotechnology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W4409640101