WHO releases ‘dirty dozen’ list of most dangerous pathogens

For the first time, scientists at the World Health Organization (WHO) have released a list of the most problematic antibiotic-resistant disease-causing microbes on the planet – a move they hope will encourage the development of new ways to combat these “priority pathogens.”

“This list is a new tool to ensure R&D responds to urgent public health needs,” Dr. Marie-Paule Kieny, the WHO’s Assistant Director-General for Health Systems and Innovation, explained in a statement. “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 antibiotics targeting this priority list of pathogens will help to reduce deaths due to resistant infections around the world,” added Professor Evelina Tacconelli, an infectious disease expert from the University of Tübingen who contributed to the list’s development. “Waiting any longer will cause further public health problems and dramatically impact patient care.”

These pathogens, dubbed “the dirty dozen” by NPR, include three families of multidrug resistant bacteria which post a critical threat – especially in hospitals and nursing homes, according to the WHO. This group includes Acinetobacter, Pseudomonas and Enterobacteriaceae such as E. coli, all of which can result in severe and potentially deadly pneumonia and blood infections.

The bacteria in this category, which also often affect patients whose care requires devices like blood catheters or ventilators, have become resistant to a vast number of antibiotics, the agency noted. That includes carbapenems and third-generation cephalosporins, which are currently the best medications available for the treatment of multi-drug resistant bacteria.

List also includes staph infections, salmonella, gonorrhea

In addition to those pathogens deemed critical, the WHO’s list also included several disease-causing agents deemed to be high priority, including gonorrhea (which is both cephalosporin- and fluoroquinolone-resistant), staph infections (which is methicillin-resistant and vancomycin-intermediate and resistant) and salmonella (which is fluoroquinolone-resistant).

“These are perhaps the bugs most likely to give you severe disease,” Dr. Elizabeth Tayler, a senior technical officer for Antimicrobial Resistance with WHO in Geneva, told NPR during an interview. “They spread very easily and we don’t have any other way of preventing them.”

High-priority pathogens also include Enterococcus faecium (vancomycin-resistant), Helicobacter pylori (clarithromycin-resistant) and Campylobacter spp. (fluoroquinolone-resistant). Rounding out the “dirty dozen” are Streptococcus pneumoniae (penicillin-non-susceptible), Haemophilus influenzae (ampicillin-resistant) and Shigella spp. (fluoroquinolone-resistant), all of which have been categorized as “medium” priority due to the availability of other treatment options.

While immunization and other methods can be used to help combat these pathogens, Dr. Tayler emphasized that they should not be underestimated. “The ‘medium’ are still very nasty bugs that can make you very sick and kill you,” she told NPR. While the WHO said that research leading to new treatment options is “vital,” it added that “better prevention of infections and appropriate use of existing antibiotics in humans and animals,” were also essential to slowing the spread of antibiotic-resistant microbes.


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