1.2 WHO priority human pathogens for antimicrobial R&D
The WHO (2017a) has also developed a different list of specific organism-resistance combinations which have the most urgent need for research and development (R&D) into new treatment approaches. Nine of the twelve organisms listed are
Priority 1: CRITICAL
- Acinetobacter baumannii – carbapenem-resistant
- Pseudomonas aeruginosa – carbapenem-resistant
- Enterobacterales – carbapenem-resistant, ESBL-producing.
Priority 2: HIGH
- Enterococcus faecium – vancomycin-resistant (VRE)
- Staphylococcus aureus, – methicillin-resistant (
MRSA ), vancomycin-intermediate and vancomycin-resistant (VISA ,VRSA ) - Helicobacter pylori – clarithromycin-resistant
- Campylobacter species – fluoroquinolone-resistant
- Salmonella species – fluoroquinolone-resistant
- Neisseria gonorrhoeae – cephalosporin-resistant, fluoroquinolone-resistant
Priority 3: MEDIUM
- Streptococcus pneumoniae – penicillin-non-susceptible
- Haemophilus influenzae – ampicillin-resistant
- Shigella species – fluoroquinolone-resistant
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Why do you think these organisms were chosen?
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Selection criteria for the WHO priority R&D pathogen list (WHO, 2017b) were:
- the severity of the infections caused
- whether treatment of the infection requires a long hospital stay
- how frequently the organism is resistant to existing antimicrobials when people in communities catch them
- how easily the organism spreads between animals, from animals to humans, and from person to person
- whether the infection can be prevented, for example through good hygiene and/or vaccination
- whether many treatment options remain
- whether new antimicrobials to treat them are already in the R&D pipeline.
Activity 2 GLASS versus priority R&D WHO lists
Compare the organisms featured on the WHO GLASS and the R&D lists and make notes of any similarities and differences. What are the reasons for any differences between the two lists?
Discussion
You will have noticed that there is some overlap between the lists but also some striking differences.
At a basic level, the GLASS list applies to species and looks at a range of resistance mechanisms rather than specifying single species-AMR combinations. This is because the lists serve different functions.
The WHO priority R&D list is about the need for new antimicrobials. It addresses the most concerning resistant organisms known currently. Some of these, like fluoroquinolone-resistant Salmonellae are mainly found in the community while others, for example VRE E. faecium, are mostly found in tertiary care settings.
In contrast, GLASS monitors a wider range of agents as its purpose is to track the development and spread of AMR overall including new patterns of resistance important in human medicine. GLASS is concerned with AMS and the organisms on the list are common and widespread. They can be cultured in most hospital microbiology laboratories, monitored and potentially controlled by good infection control and AMS.
Some rarely encountered organisms like VRSA are commonly tested for in clinical laboratories, while organisms like H. pylori, which are very widespread in the population, are not. Attempts to culture H. pylori are rare in routine clinical laboratories, so it would not be practical to include these in the GLASS surveillance.
Activity 3 WHO priority R&D list in context of One Health
Which pathogen-resistance combinations in the WHO priority R&D list are also important from a
Discussion
The WHO R&D priority list includes several pathogens of One Health importance which are found in livestock:
- Enterobacterales – carbapenem-resistant, ESBL-producing
- Enterococcus faecium – vancomycin-resistant (VRE)
- Staphylococcus aureus – methicillin-resistant (MRSA), vancomycin-intermediate and resistant (VISA, VRSA); the latter are unlikely to be detected in routine enteric samples but can be cultured from samples of animal origin
- Campylobacter species – fluoroquinolone-resistant
- Salmonella species – fluoroquinolone-resistant.
1 Resistance problems of global concern
