ROME/GENEVA: The United Nations’ World Health Organization (WHO) has published its first ever list of antibiotic-resistant “priority pathogens”—a catalog of 12 families of bacteria that pose the greatest threat to human health.
The list was drawn up in a bid to guide and promote research and development (R&D) of new antibiotics, as part of the efforts to address growing global resistance to antimicrobial medicines.
The list highlights in particular 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, WHO reported on February 27.
“This list is a new tool to ensure R&D responds to urgent public health needs,” said Dr Marie-Paule 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.”
New resistance mechanisms are emerging and spreading globally, threatening our ability to treat common infectious diseases, resulting in prolonged illness, disability, and death.
Without effective antimicrobials for prevention and treatment of infections, medical procedures such as organ transplantation, cancer chemotherapy, diabetes management and major surgery (for example, caesarean sections or hip replacements) become very high risk.
3 categories of urgency
The WHO list is divided into three categories according to the urgency of need for new antibiotics: critical, high, and medium priority.
The most critical group of all includes 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.
They include Acinetobacter, Pseudomonas and various Enterobacteriaceae (including Klebsiella, E. coli, Serratia, and Proteus). 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.
The second and third tiers in the list—the high and medium priority categories—contain other increasingly drug-resistant bacteria that cause more common diseases such as gonorrhoea and food poisoning caused by salmonella.
Tuberculosis—whose resistance to traditional treatment has been growing in recent years—was not included in the list because it is targeted by other, dedicated programs, says the UN specialized body.
“Other bacteria that were not included, such as streptococcus A and B and chlamydia, have low levels of resistance to existing treatments and do not currently pose a significant public health threat,” WHO said.
WHO explained that 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.
“New antibiotics targeting this priority list of pathogens will help to reduce deaths due to resistant infections around the world,” said Prof 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 on patient care,” she warned.