Superbugs killing millions globally
World war on antibiotic-resistant bacteria
THE World Health Organisation (WHO) has announced its first list of antibiotic-resistant “priority pathogens”, detailing 12 families of bacteria that agency experts say pose the greatest threat to human health and kill millions of people every year.
The list is divided into three categories and prioritised by the urgency of the need for new antibiotics. The purpose is to guide and promote the research and development of new drugs, officials say.
Most of the pathogens are among the nearly two dozen antibiotic-resistant microbes that the US Centres for Disease Control and Prevention warned in a 2013 report could cause potentially catastrophic consequences if the US did not act quickly to combat the growing threat of antibiotic-resistant infections.
“This list is not meant to scare people about new superbugs,” says Marie-Paul Kieny, an assistant director-general at the WHO. “It is intended to signal research and development priorities to address urgent public health threats.”
Superbugs the WHO considers the highest priority are responsible for severe infections and high mortality rates, especially among patients in intensive care or using ventilators and blood catheters, as well as among transplant recipients and people undergoing chemotherapy. While these pathogens are not widespread, “the burden for society is now alarming”, she says.
Included in this highest-priority group is CRE, or carbapenem-resistant Enterobacteriaceae, which US health officials have dubbed “nightmare bacteria”. In some instances, it kills up to 50% of patients who become infected.
Also included in this critical group is Acinetobacter baumannii; the infections tied to it typically occur in ICUs and with very sick patients.
Also listed is Pseudomonas aeruginosa, which can be spread on the hands of healthcare workers or by equipment that gets contaminated and is not properly cleaned.
The WHO’s list follows a summit on superbugs that world leaders held at the end of last year – only the fourth time they had addressed a health issue at the UN General Assembly.
The list’s second and third tiers – the high and medium priority categories – cover bacteria that cause more common diseases, such as gonorrhoea and food poisoning caused by salmonella.
While they are not associated with significant mortality rates, “they have a dramatic health and economic impact, particularly in low-income countries”, Kieny says.
Although there has been renewed interest and research investment in antibiotics because of the growing threat that antibiotic resistance poses, much of the work is more focused on antibiotics with a broad range.
“We have to focus specifically on a much smaller range of bacteria”, specifically targeting the three highest-priority pathogens, Kieny says.
Drug companies also tend to focus more on gram-positive bacteria that tend to colonise the skin of healthy individuals and generate less resistance, says Evelina Tacconelli, who heads the infectious diseases division at the University of Tübingen in Germany, which helped develop the WHO list.
By comparison, gram-negative bacteria more frequently colonise intestinal reservoirs and can cause sepsis and severe urinary tract infections, especially among elderly patients.