What bacteria causes the most death?

The bacteria that causes the most death globally is Mycobacterium tuberculosis, which causes tuberculosis, killing approximately 1.3 to 1.5 million people every year, making it the deadliest bacterial infection worldwide and the leading infectious disease killer after COVID during pandemic years. Tuberculosis spreads through airborne particles when infected people cough, requiring negative pressure rooms for hospital containment, and it primarily affects lungs but can affect other organs, with drug-resistant TB becoming increasingly deadly and difficult to treat. Other bacteria that cause extremely high numbers of deaths include Streptococcus pneumoniae which causes pneumonia, meningitis, and sepsis killing hundreds of thousands of children under five and elderly adults annually, Staphylococcus aureus including MRSA which causes sepsis and hospital infections killing tens of thousands, Klebsiella pneumoniae and Escherichia coli which cause sepsis and urinary infections, and Vibrio cholerae which causes cholera outbreaks that can kill rapidly from dehydration. In terms of historical deaths, Yersinia pestis caused plague pandemics killing tens of millions. According to recent Lancet studies on antimicrobial resistance, the top bacteria associated with deaths due to resistance include E. coli, S. aureus, K. pneumoniae, S. pneumoniae, and M. tuberculosis. Factors that increase deaths include lack of access to antibiotics, vaccination, clean water, and good ventilation, with poor indoor air quality contributing to spread. Prevention includes vaccination for pneumonia, prompt antibiotic treatment, and infection control with HEPA filtration.