Global Mortality Associated with 33 Bacterial Pathogens
Reducing mortality from infections is clearly one of the global public health priorities. Earlier studies have estimated the deaths associated with drug-resistant infections and sepsis. The conclusion was: infections are still the leading cause of death worldwide.
Recently The Lancet published a study funded by Bill & Melinda Gates Foundation, Wellcome Trust, and the Department of Health and Social Care, using UK aid funding managed by the Fleming Fund. Probably, it is the first study that presents global comprehensive estimates of mortality due to 33 bacterial pathogens in 11 major infectious syndromes. After all, understanding the global burden of common bacterial pathogens is vital for finding out the greatest threats to public health.
How was the research done? The study covered mortality associated with 33 bacteria, using data from all ages and gender in 204 countries or territories in 2019. And included resistant, as well as susceptible to antimicrobial bacteria, except Mycobacterium tuberculosis, as they are already under the scrutiny of a global public health initiative. Used information was derived from death certificates, hospital discharge records, mortality surveillance, literature reviews, microbial data, and estimates from the Global Burden of Diseases, Injuries, and Risk Factors Study. Three modeling steps were used to estimate the number of deaths related to each pathogen: deaths in which infection played a role, deaths because of the infection that related to a given infectious syndrome, and deaths because of the infection that related to a given pathogen.
What were the results? From nearly 13,7 million (95% UI 10,9–17,1) infection-related deaths in 2019, 7,7 million (5,7–10,2) were related to 33 bacterial pathogens (susceptible, as well as resistant to antimicrobials) across the 11 infectious syndromes the study looked at. Based on the study, relative to all deaths worldwide in 2019, deaths associated with 33 bacterial pathogens were 13,6% and 56,2% associated with sepsis. Among the investigated bacteria - Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae, Klebsiella pneumoniae, and Pseudomonas aeruginosa - were five leading pathogens responsible for 54,6% of deaths. The deadliest syndromes and pathogens varied by age and location. The mortality rate associated with these pathogens, standardized by age, was highest in the sub-Saharan Africa super-region, 230 deaths per 100 000 population, and lowest in the high-income super-region, 52 deaths per 100 000 population. Staphylococcus aureus was associated with the highest number of deaths among persons over 15 years worldwide, as well as the leading bacterial cause of death in 135 countries. Such a pathogen among children under 5 years was Streptococcus pneumoniae. More than 6 million deaths in 2019 occurred as a result of three bacterial infectious syndromes: lower respiratory infections - 4 million deaths, bloodstream infections - 2,91 million deaths, and peritoneal and intra-abdominal infections - 1,28 million deaths.
What conclusions can be drawn? Notwithstanding considerable variation in the distribution across infectious syndromes and locations, the 33 bacterial pathogens studied are a significant source of health loss worldwide. They caused 1 in 7 deaths in 2019, with five pathogens linked to slightly more than half of those deaths. In previous years, only one (Streptococcus pneumoniae) of the five most clinically significant pathogens they identified was under the scrutiny of global surveillance and public health initiatives. But all of them should be considered an urgent priority for invention by the global health community, as these bacterial pathogens were the second leading cause of death in the world in 2019, compared to the GBD Level 3 underlying causes of death. A strategy to reduce the burden of bacterial infections should include the prevention of these infections, optimized use of antibiotics, improved capacity for microbiological analysis, vaccine development, and wider use, as well as improvement of available vaccines. The study is extremely important, as its result can be used to prioritize vaccine need, demand, and development.
You can see details of this study at: https://www.thelancet.com/