Antibiotic-resistant "priority pathogens" – a catalogue 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 WHO’s 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 priority pathogens list for R&D of new antibiotics

Priority 1: CRITICAL

1.        Acinetobacter baumannii, carbapenem-resistant

2.        Pseudomonas aeruginosa, carbapenem-resistant

3.        Enterobacteriaceae, carbapenem-resistant, ESBL-producing

Priority 2: HIGH

1.        Enterococcus faecium, vancomycin-resistant

2.        Staphylococcus aureus, methicillin-resistant, vancomycin-intermediate and resistant

3.        Helicobacter pylori, clarithromycin-resistant

4.        Campylobacter spp., fluoroquinolone-resistant

5.        Salmonellae, fluoroquinolone-resistant

6.        Neisseria gonorrhoeae, cephalosporin-resistant, fluoroquinolone-resistant

Priority 3: MEDIUM

1.        Streptococcus pneumoniae, penicillin-non-susceptible

2.        Haemophilus influenzae, ampicillin-resistant

3.        Shigella spp., fluoroquinolone-resistant

Source: WHO