WHO Identified Antibiotic-Resistant ‘Priority Pathogens’

Since the discovery of penicillin, almost every type of bacteria is becoming resistant to the antibiotic specially designed to treat it. Globally, at least 700,000 die each year from antibiotic-resistant infections. If we fail to take the necessary precautions, antibiotic-resistant could kill some 10 million people a year by 2050. That’s one death every three seconds.

For the first time ever, the World Health Organization (WHO) published a list of bacteria with the highest priority needs for new antibiotics. The priority list enumerated 12 bacterial threats, grouping them into three categories: critical, high, and medium.

Priority 1 Critical: The bacteria featured on this critical list were chosen based on the level of drug resistance that already exists for each, the numbers of deaths they cause, the frequency with which people become infected with them outside of hospitals, and the burden these infections place on health care systems.

Priority 1 Critical Pathogens
  • Acinetobacter baumannii: resistant to important antibiotics called carbapenems; highly drug-resistant bacteria that can cause a range of infections for hospitalized patients, including pneumonia, wound, or blood infections.
  • Pseudomonas aeruginosa: resistant to carbapenems; can cause skin rashes and ear infections in healthy people but also severe blood infections and pneumonia when contracted by immunocompromised people in the hospital.
  • Enterobacteriaceae: resistant to both carbepenems and another class of antibiotics, cephalosporins; live in the human gut and includes bugs such as E. coli and Salmonella.

Notably missing from the list is the bacterium that causes tuberculosis (TB). Mycobacterium tuberculosis was not included because the need for new antibiotics to treat TB has already been designated the highest priority.

Priority 2 High: Pathogens in this category can cause hard-to-treat infections in healthy people but generally don’t have a high mortality risk.

Priority 2 High Priority Pathogens

Priority 3 Medium: Bacteria in this list still have effective antibiotic options but are becoming increasingly resistant. While less dangerous than the critical pathogens, they are also more widespread in the community, especially in nursing homes, where there is more uncontrolled usage of antibiotics.

Priority 3 Medium Priority Pathogens

WHO could not provide estimates on how many people die from being infected by these pathogens, because international codes for disease currently do not account for deaths caused by antimicrobial-resistant pathogens.

The US Centers for Disease Control and Prevention (CDC) estimates that at least 23,000 Americans a year die as a direct result of antibiotic-resistant infections, and the European Centre for Disease Prevention and Control (ECDC) says drug-resistant bacteria are responsible for 25,000 annual deaths in Europe. A 2014 report led by British economist Lord Jim O’Neill estimated that, if left unchecked, antimicrobial-resistant pathogens could cause 10 million deaths a year.

Reducing inappropriate and unnecessary use of antibiotics in hospitals and in agriculture will help ease the problem, but the best solution is to invest in the development of new antibiotics. Unfortunately, that’s not being done. The reasons for this are both scientific and financial. It costs upward of $2 billion to develop one new drug. Because antibiotics have traditionally been cheap and patients don’t take them for very long, there’s no economic incentive for the drug companies to develop them. The total market for antibiotics is relatively large — sales of about $40 billion a year — but only about $4.7 billion comes from sales of patented antibiotics.

Antibiotic R&D

Developers should be provided an opportunity to make a reasonable return from useful products. Interventions to make this possible would include advance market commitments and market-entry rewards. In October 2015, the UK and China agreed to establish a global research and development fund to attract $1.5 billion for investment in research to reduce the spread of antimicrobial resistance. But, overall, there’s insufficient private and public investment in R&D focused on the problem. Harmonized regulations and clinical trial networks can also play an important role to lower R&D costs for drug developers.

While more research is essential, it cannot solve the problem by itself. To address resistance, there must also be better prevention of infections (hand washing, vaccination) and appropriate use of existing antibiotics in both humans and animals, as well as rational use of novel antibiotics that are developed in future.