Question: what is the deadlist bacteria ?

Samuel Ellis answered on 10 Mar 2015:

Obviously a lot of bacteria are very deadly. There have been some extremely serious outbreaks of bacteria in history, with the Black Death plague particularly famous. Caused by a bacteria called Yersinia pestis, the Black Death killed around 1 in 3 of ALL people in Europe around in the years 1346–53!

As for the most deadly bacteria to catch, a few of the more famous bacterial diseases have very high mortality rates, meaning a large proportion of people who are infected will die. An example is Cholera, which is thought to kill more than half of people infected if not treated. Thankfully antibiotics are very effective against the disease, but not always available in the developing world.

The bacteria which causes the most deaths in the world is Mycobacterium tuberculosis, which causes the disease Tuberculosis (TB). TB is second only to HIV/AIDS (which is a virus not bacteria) as the biggest infectious killer. In 2013, around 9 million people fell ill with TB and 1.5 million died from the disease! TB used to be a big problem in the UK around a hundred years ago, but since the development of antibiotics and vaccines it is very rare here now, thankfully!