WHO ranks 12 bacteria families that pose greatest health risks

The World Health Organization (WHO) has compiled a dirty-dozen list of sorts, detailing 12 families of bacteria that it believes pose the greatest threat to human health because of their growing resistance to antibiotics.

The list was created to help guide, prioritize and promote research and development of new antibiotics and address global resistant to antimicrobial medicines.

"This list is a new tool to ensure that R&D [research and development] responds to urgent public health needs," says Marie-Paule Kieny, Ph.D., WHO's assistant director-general for health systems and innovation. "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."

Although WHO’s main goal for the list is to spur development of antibiotic solutions, the organization says that drugs alone cannot eliminate the problem. Better prevention of infections, appropriate use of existing antibiotics in humans and animals, and rational use of any new antibiotics that are developed in the future should be part of a total plan to help eradicate antibiotic resistance.

The WHO list is divided into three categories according to the urgency of need for new antibiotics: critical, high and medium priority.

Priority 1: Critical

• Acinetobacter baumannii, carbapenem-resistant
• Pseudomonas aeruginosa, carbapenem-resistant
• Enterobacteriaceae, carbapenem-resistant, ESBL (extended-spectrum beta-lactamase)-producing

Priority 2: High

• Enterococcus faecium, vancomycin-resistant
• Staphylococcus aureus, methicillin-resistant, vancomycin-intermediate and -resistant
• Helicobacter pylori, clarithromycin-resistant
• Campylobacter spp., fluoroquinolone-resistant
• Salmonellae, fluoroquinolone-resistant
• Neisseria gonorrhoeae, cephalosporin-resistant, fluoroquinolone-resistant

Priority 3: Medium

• Streptococcus pneumoniae, penicillin-nonsusceptible
• Haemophilus influenzae, ampicillin-resistant
• Shigella spp., fluoroquinolone-resistant

The list was developed in collaboration with the division of infectious diseases at the University of Tübingen, Germany, using a multicriteria decision-analysis technique vetted by a group of international experts. The criteria included 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.

"New antibiotics targeting this priority list of pathogens will help to reduce deaths due to resistant infections around the world," says Proffesor Evelina Tacconelli, head of the division of infectious diseases at the University of Tübingen and a major contributor to the development of the list. "Waiting any longer will cause further public health problems and dramatically impact patient care."