WHO Publishes List of Bacteria for Which New Antibiotics Are Urgently Needed

Announcement highlights threat of multidrug-resistant gram-negative pathogens

The World Health Organization (WHO) has published its first list of antibiotic-resistant “priority pathogens”––a catalogue of 12 families of bacteria that pose the greatest threat to human health. The list was composed to guide and promote the development of new antibiotics.

In particular, the list highlights the threat of gram-negative bacteria that are resistant to multiple antibiotics. These 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.

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

The “critical” group includes multidrug-resistant bacteria that pose a particular threat in hospitals, in nursing homes, and among patients whose care requires devices such as ventilators and blood catheters. They can cause severe and often deadly infections, such as bloodstream infections and pneumonia. These bacteria have become resistant to a large number of antibiotics, including carbapenems and third-generation cephalosporins––the best available antibiotics for treating multi-drug resistant bacteria. They are:

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

The second and third tiers in the list––the high- and medium-priority categories––include other increasingly drug-resistant bacteria that cause more-common diseases, such as gonorrhea and food poisoning caused by Salmonella.

The “high priority” group includes:

  • 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

The “medium priority” group includes:

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

Tuberculosis was not included in the list because it is targeted by other dedicated programs, the WHO said. Other bacteria that were not included, such as chlamydia and Streptococcus A and B, have low levels of resistance to existing treatments and do not currently pose a significant public health threat, the organization said.

“New antibiotics targeting this priority list of pathogens will help to reduce deaths due to resistant infections around the world,” remarked Professor 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 will dramatically impact patient care.”

While more research and development are vital, they cannot solve the problem alone. To address resistance, there must also be better prevention of infections and appropriate use of existing antibiotics in humans and animals, as well as rational use of any new antibiotics that are developed in future, the WHO pointed out.

Source: WHO; February 27, 2017.