In the face of rising antibiotic resistance, the World Health Organisation (WHO) has published its first ever list of the deadliest superbugs that threaten human health.
This so-called dirty dozen encompasses 12 families of dangerous bacteria that have developed resistance to the drugs used to treat common infections. Antibiotic-resistance costs some 700,000 lives each year, and if the phenomenon can't be halted, experts predict that the number could grow to 10 million deaths annually by 2050.
The list is divided into three urgency categories – critical, high, and medium – representing how badly we need new antibiotics to treat their respective superbugs.
The "critical" section includes three bacteria – Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacteriaceae – which are all resistant to multiple drugs, and can cause a range of serious infections, including pneumonia and blood infections.
These species are all examples of what's called gram-negative bacteria – bugs that usually live in the gut that have developed two cellular membranes, making it harder for drug molecules to penetrate them.
The nine other pathogens making up the high and medium urgency categories are bacteria that cause more common diseases – such as gonorrhoea and food poisoning – but which can also be deadly, and are increasingly resistant to drugs.
These include methicillin-resistant Staphylococcus aureus (MRSA), Salmonellae, and Haemophilus influenzae.
The list is a grave acknowledgement by the WHO that current pharmaceutical research efforts to curb antibiotic resistance aren't doing enough to curb the risks posed by these superbugs.
While antibiotics require a huge amount in terms of research and development costs, they are only taken by patients for a short time, meaning only a small volume is sold.
One solution could be to alter how companies and research institutions are financially rewarded for developing new antibiotics, rather than just generating their profits through products sales.
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