Priority pathogens list

The World Health Organisation (WHO) has issued a call to action to develop new antibiotics with its first ever list of antibiotic-resistant ‘priority pathogens’. This catalogue of 12 families of bacteria that pose the greatest threat to human health is intended to guide R&D priorities.

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 allowing other bacteria to become drug-resistant too.

‘Antibiotic resistance is growing, and we are fast running out of treatment options,’ says Marie-Paule Kieny, WHO’s assistant director-general for Health Systems and Innovation.  ‘If we leave it to market forces alone, the new antibiotics we most urgently need are not going to be developed in time.’

The WHO list is divided into three categories according to the urgency of need. The most critical group includes multidrug-resistant bacteria that pose a particular threat in hospitals, nursing homes, and among patients using 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.

‘It’s a dirty little secret that the antibiotic pipeline is drying up and there are hardly any new ones to fight multi-resistant bacterial infections,’ comments Penelope Bryant, honorary fellow in infection and immunity at Murdoch Childrens Research Institute in Melbourne, Australia. ‘It costs a lot of money to develop a drug, so the WHO releasing this list of urgent priority bugs is an important call to action to develop new antibiotics to prevent more deaths.’