The World Health Organisation (WHO) has published its first-ever list of antibiotic-resistant “priority pathogens”, a catalogue of 12 bacteria families that pose a great 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 WHO’s efforts to address growing resistance among bacteria to medicines currently in use. It highlights the threat of gram-negative bacteria that have inculcated the ability to resist treatment, and are capable of passing on genetic material that allows other microbes to become drug-resistant as well. Consequently, ailments such as urinary tract infections – which were eminently treatable until a few years ago – have now become life-threatening.
“This list is a new tool to ensure that R&D responds to urgent public health needs,” says 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, the new antibiotics we urgently need won’t be developed in time.”
The WHO list is divided into three categories: critical, high and medium priority. The most critical group includes multidrug resistant bacteria that target hospitals, nursing homes and patients dependent on life-preserving devices such as ventilators and blood catheters. They include Acinetobacter, Pseudomonas and various Enterobacteriaceae (such as Klebsiella, E coli, Serratia and Proteus). They can cause 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 option 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 due to salmonella.
The matter will come up at a meeting of G20 health experts in Berlin this week. “We need effective antibiotics for our health systems. We have to take joint action today for a healthier tomorrow. Therefore, we will discuss and bring the G20’s attention to the fight against antimicrobial resistance. WHO’s first global priority pathogen list is an important new tool to secure and guide R&D related to new antibiotics,” says Mr Hermann Gröhe, federal minister of health, Germany.
The list is intended to spur governments to put in place policies that incentivise basic science and advanced R&D by both publicly funded agencies and private sector entities investing in new antibiotic discovery. It will provide guidance to new R&D initiatives such as the WHO/Drugs for Neglected Diseases initiative (DNDi) Global Antibiotic R&D Partnership, which is engaging in the not-for-profit development of new antibiotics.
Tuberculosis, which has become increasingly resistant to traditional treatment in recent years, was not included in the list because it is targeted by other dedicated programmes. 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.
The list was developed in collaboration with the Division of Infectious Diseases at the University of Tübingen, Germany, using a multi-criteria decision analysis technique vetted by a group of international experts. The criteria for selecting pathogens on the list were: How deadly their infections are; whether their treatment requires long hospital stays; how frequent is their resistance to existing antibiotics; how easily they spread from animal to animal, 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 reduce deaths due to resistant infections across the world,” says Prof Evelina Tacconelli, head of the infectious diseases division at the University of Tübingen and a major contributor to the list. “Waiting any longer will cause further public health problems and dramatically impact patient care.”
While more R&D is vital, it’s not enough to curb bacterial resistance to drugs. To address the issue, the authorities must ensure better prevention of infections and appropriate use of existing antibiotics in humans and animals – besides rational application of new drugs developed in the future.
India has been doing its bit to combat the problem too. “The threat of anti-microbial resistance is very real, and we always knew it was coming. This is why we have been working to combat the threat for a while now. A national action plan to tackle it is underway, and should be out anytime,” said a senior researcher at the National Centre for Disease Control.