Question: What isthe deadliest bacteria known to man?

Robert Hampson answered on 19 Nov 2014:

There are two ways of classifying how deadly a bacteria is.

1) Most number of deaths caused: In this category, the most deadly is likely to be TB. One third of the worlds population are infected with TB and it causes quite a high number of deaths. The only infectious disease that kills more is HIV.

2) Most deaths per infection: This is a better way of evaluating the danger of death to those who have just been infected with the bacteria. However, this kind of assessment can also change depending on the quality of medical health care available. For example, veterans from Iraq and Afghanistan have recently had high infection rates of the bacteria Acinetobacter baumannii. This rapidly became resistant to most known antibiotics and because it seemed to be particularly prevalent in Iraq, it was nicknamed “Iraqibacter”. Although this is a very dangerous and nasty infection, the recorded death rate is quite low because veterans have access to fairly high quality advanced medicine. The medical services used a quite old but rare antibiotic called Colistin or Polymixin to treat the infection. This is normally not used because it has a high probability of causing kidney damage. This kind of medicine probably wouldn’t have been available for Iraqi civilians. Generally, resistant infections have a high death rate per infection because they are harder to treat. I don’t know which specific bacteria has the highest number in this classification system though.