First-Ever Priority Pathogens List Published by WHO

The World Health Organization (WHO) recently published, for the first time, a list of antibiotic-resistant bacteria—from 12 families—that are priority pathogens that urgently need antibiotics to treat them. WHO hopes that this list will drive research & development (R&D) efforts to create these new antibiotics.

The list was developed in collaboration with the Division of Infectious Diseases at the University of Tübingen, Germany through the use of a multi-criteria decision analysis technique. According to WHO’s press release on the list, “the criteria for selecting pathogens on the list were: how deadly the infections they cause are; whether their treatment requires long hospital stays; how frequently they are resistant to existing antibiotics when people in communities catch them; how easily they spread between animals, from animals to humans, and from person to person; whether they can be prevented (e.g. through good hygiene and vaccination); how many treatment options remain; and whether new antibiotics to treat them are already in the R&D pipeline.”

Notably highlighted in the list are “gram-negative bacteria that are resistant to multiple antibiotics.” The threat of these pathogens has been seen across the world, most recently in China and the United States. These bacteria are particularly alarming because of their abilities to pass along the “genetic material that allows other bacteria to become drug-resistant as well.”

"This list is a new tool to ensure R&D responds to urgent public health needs," Dr Marie-Paule Kieny, WHO's Assistant Director-General for Health Systems and Innovation is quoted as saying in the press release. "Antibiotic resistance is growing, and we are fast running out of treatment options. If we leave it to market forces alone, the new antibiotics we most urgently need are not going to be developed in time."

The list is included below:

WHO Priority Pathogens List for R&D of New Antibiotics

Priority 1: CRITICAL

1. Acinetobacter baumannii, carbapenem-resistant
2. Pseudomonas aeruginosa, carbapenem-resistant
3. Enterobacteriaceae, carbapenem-resistant, ESBL-producing

Priority 2: HIGH

1. Enterococcus faecium, vancomycin-resistant
2. Staphylococcus aureus, methicillin-resistant, vancomycin-intermediate and resistant
3. Helicobacter pylori, clarithromycin-resistant
4. Campylobacter spp., fluoroquinolone-resistant
5. Salmonellae, fluoroquinolone-resistant
6. Neisseria gonorrhoeae, cephalosporin-resistant, fluoroquinolone-resistant

Priority 3: MEDIUM

1. Streptococcus pneumoniae, penicillin-non-susceptible
2. Haemophilus influenzae, ampicillin-resistant
3. Shigella spp., fluoroquinolone-resistant

WHO notes that those pathogens included in the most critical group are those “multidrug resistant bacteria that pose a particular threat in hospitals, nursing homes, and among patients whose care requires devices such as ventilators and blood catheters.” Those pathogens in the high and medium categories include those that lead to drug-resistant gonorrhea and food poisoning, among others.

According to WHO, “the list is intended to spur governments to put in place policies that incentivize basic science and advanced R&D by both publicly funded agencies and the private sector investing in new antibiotic discovery.” In addition, the list, “will provide guidance to new R&D initiatives such as the WHO/Drugs for Neglected Diseases initiative (DNDi) Global Antibiotic R&D Partnership that is engaging in not-for-profit development of new antibiotics.”

Researchers may notice that tuberculosis is notably absent from the list, but WHO explains that this was intentional since multi-drug resistant tuberculosis is the focus of other dedicated programs. In addition, other resistant bacteria, such as streptococcus A and B and chlamydia, were not included because their resistance is considered low and they do not pose a “significant public health threat” at this time.