Global deaths from WHO's priority drug-resistant bacteria rose from 1990 to 2021

The World Health Organization's Bacterial Priority Pathogens List names the antibiotic-resistant bacteria judged to pose the most serious threat to human health, and so sets much of the research and drug-development agenda. A study published on 22 October in BMJ Public Health asks a basic question about that list: over the long run, is the burden it describes getting better or worse? Using more than three decades of data, the answer is worse, though unevenly [s1].

A rising global rate

The authors conducted a systematic analysis of the years 1990 to 2021, drawing on the Global Burden of Disease study's database for measuring infectious causes and resistance outcomes [s1]. Over that 32-year span, global mortality attributable to the priority antibiotic-resistant pathogens rose from 5.47 to 6.12 per 100,000 population, an annual net drift of 0.086% [s1].

That modest-looking average hides a sharp divergence by age. Mortality from these pathogens declined among children under five but increased among the middle-aged and elderly, peaking in the 40–44 and the 95-and-over age bands [s1]. The authors attribute much of the rise to two organisms: carbapenem-resistant Klebsiella, with an average annual percentage change of 2.1% to 2.4% across affected groups, and Escherichia coli, at 1.6% to 2.2% [s1].

The age pattern is the part most worth dwelling on. A falling death rate in the under-fives is the kind of progress that vaccination, cleaner water and better paediatric care would be expected to deliver, and it is real. But the gains do not carry through life: the same pathogens are killing more people in middle and old age than they did three decades ago, which is consistent with populations living longer into the years when drug-resistant infections — in hospitals, after surgery, alongside chronic disease — become hardest to treat. The authors used age-period-cohort modelling precisely to separate those strands, and it is the period-level rise in older adults that drives the global figure [s1].

Tuberculosis, and the youngest patients

The most striking single trend is in drug-resistant tuberculosis, whose mortality rose across all ages — and fastest of all in neonates, at an average annual percentage change of 7.4% (95% confidence interval 6.6% to 8.1%) [s1]. A rising death rate from multidrug-resistant tuberculosis in newborns is a signal of transmission and treatment failure reaching the most vulnerable patients, and it runs against the broader global decline in tuberculosis deaths over the same decades.

Where the burden is shifting

The regional picture is one of widening contrast. High-income Asia Pacific saw the steepest decline in mortality, at an average annual percentage change of −2.5% (95% CI −2.7% to −2.3%) [s1]. Eastern Europe, by contrast, showed the sharpest increase, at 1.2% (95% CI 0.2% to 2.2%), driven by multidrug-resistant tuberculosis (7.7%), carbapenem-resistant Klebsiella (3.5%) and vancomycin-resistant Enterococcus (3.1%) [s1]. In southern sub-Saharan Africa, the standout was a rise in fluoroquinolone-resistant Salmonella Typhi, at 4.6% (95% CI 2.5% to 6.8%) [s1].

The study also tracked inequality directly. Over the 32 years, the slope index of inequality in the mortality burden narrowed from −333.65 to −282.20, while the concentration index widened from −0.28 to −0.31 [s1]. The two measures point in different directions, and the authors read them together as a burden that remains concentrated in lower-development countries even as some absolute gaps close — a reason, they argue, to allocate healthcare resources toward the regions carrying the most resistance.

How to read it

The usual cautions for Global Burden of Disease estimates apply. These are modelled figures built from surveillance and vital-registration data of uneven quality, and resistance attribution in particular depends on assumptions about what would have happened had the infection been susceptible. The uncertainty intervals around individual pathogen trends are wide. The study reports associations and trajectories, not the causes behind them, and a per-100,000 rate says nothing about the total number of deaths, which depends on how populations grew and aged over the period.

What the analysis does establish is a direction of travel. Across the pathogens WHO has flagged as most dangerous, the age-standardised mortality rate did not fall between 1990 and 2021 — it rose, and the rise fell hardest on older adults, on newborns through drug-resistant tuberculosis, and on parts of the world least equipped to absorb it. For a list meant to concentrate the world's attention, the long trend is the argument that it still needs to.