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WHO says these bacteria pose greatest risk to humans

Escherichia coli bacteria in a colored electron-scanning micrograph
PASIEKA | Getty Images
Escherichia coli bacteria in a colored electron-scanning micrograph

The World Health Organization has published its first list of antibiotic resistant "priority pathogens" that pose the biggest threats to humans.

The agency created the list to spur research and development for new antibiotics that can counter bacteria that are increasingly resistant to treatment.

The bacteria that pose the greatest threat, those considered "critical" priority, are strains of bacteria resistant to multiple antibiotics that pose threats to patients in hospitals, nursing homes, or under certain kinds of treatment.

One bacteria not included in the WHO list is the one that causes tuberculosis because there is "already consensus that tuberculosis is the most important priority for R&D for new antibiotics," WHO's Marie-Paule Kieny said at a press conference Monday.

The list was compiled by the WHO and researchers from the Division of Infectious Diseases at the University of Tuebingen, Germany. The team used a list of criteria to evaluate each strain, considering things such as how deadly the infections from a bacterial strain can be, how frequently they show resistance to treatment, whether infections cause long stays in hospitals, and how easily they spread among animals and people.

"This list is a new tool to ensure R&D responds to urgent public health needs," said Kieny, 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."

The list is a new step for the WHO, but it is not the first time a public health agency has listed high-risk bacterial strains. The U.S. Centers for Disease Control and Prevention also published a lengthy report on antibiotic resistance in 2013, including a similar list of exceptionally concerning strains of antibiotic resistant bacteria.

In that report, the CDC cited research suggesting antibiotic resistance costs $20 billion in excess direct health-care costs per year (in 2008 dollars), and an additional $35 billion a year in lost productivity.

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