Five pathogens - Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae, Klebsiella pneumoniae, and Pseudomonas aeruginosa - accounted for the majority of global deaths due to infectious diseases in 2019. In this first-time audit of deaths published in The Lancet, bacterial infections were found to be the second most important cause of death after ischemic heart disease.¹

In this study, researchers assessed the infection-related deaths that occurred in 2019 in 204 countries in 11 infectious diseases caused by 33 clinically significant bacterial species. Data for this analysis was obtained from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 and the Global Burden of Antimicrobial Resistance 2019 study. Mycobacterium tuberculosis was not included in this analysis because there is already an End TB strategy in places globally with many countries having dedicated TB control programs. The researchers estimated the number of infection-related deaths, the infectious disease implicated in the deaths and the pathogens causing the infectious disease. Aided by these three modelling steps, number of deaths associated with each pathogen was estimated.

A total of 14 million infection-related deaths were recorded in 2019. Of these, nearly 8 million deaths were associated with the 33 species of bacteria examined. Amongst all the bacterial species evaluated, five bacteria namely Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae, Klebsiella pneumoniae, and Pseudomonas aeruginosa accounted for nearly 55% of deaths. S. aureus was associated with more than 1 million deaths globally in 2019, while more than 500,000 deaths each could be attributed to the remaining four pathogens.

Lower respiratory infections (4 million), bloodstream infections (2.91 million) and peritoneal and intra-abdominal infections (1.28 million) accounted for the majority of deaths in 2019. S. aureus was associated with 653,000 deaths due to LRTIs and 299,000 deaths due to blood stream infections, while E. coli was linked to 290,000 deaths due to peritoneal and intra-abdominal infections. A regional difference was noted with highest mortality burden reported in sub-Saharan Africa (230 deaths per 100,000 population) vis a vis 52.2 deaths per 100,000 population in the high-income regions. The major pathogen responsible for deaths in persons aged ≥15 years was S. aureus, while among children ≤5 years, the major organism causing death was S. pneumoniae.

This study, which was conducted in the pre-Covid era, has identified 5 pathogens that were implicated in majority of deaths that occurred in 2019 due to infectious causes. As the “second leading cause” of death globally in 2019, an urgent action and intervention is necessary starting with increased and better surveillance. Prevention of infection, rational use of antibiotics, improved microbiological testing and vaccination are few approaches to tackle this high burden of bacterial infections and prevent mortality.

Reference

1. GBD 2019 Antimicrobial Resistance Collaborators. Global mortality associated with 33 bacterial pathogens in 2019: a systematic analysis for the Global Burden of Disease Study 2019. Lancet. 2022 Nov 18:S0140-6736(22)02185-7. doi: 10.1016/S0140-6736(22)02185-7.