Germs are most likely the most dangerous things on Earth because of their reproductive system and being almost unkillable until the first vaccine was made in 1879 by Louis Pasteur, but the real question is where do germs come from? In the 1670's was when the germ theory was first invented, no one knows yet where germs came from but we do know how they spread, what types there are, and how diseases are made.
In the bacteria group there are three types and two groups and two gram types of bacteria. The first gram group is gram positive bacteria, the bacteria species Staphylococcus and Streptococcus are both gram positive. Gram positive bacteria and Gram negative bacteria are both friendly, meaning they do no harm and preform useful functions in the human body and in the environment. There are different gram positive bacilli such as Corynebacterium diphtheriae, Listeria monocytogenes and some bacteria from the Lactobacillus group. This group also contains two very dangerous bacteria. One is the Bacillus species that causes anthrax, and the other is Clostridium which causes tetanus and botulism, a deadly form of food poisoning. There are also different gram negative bacteria such as the meningococcus and the gonococcus bacteria, gram negative bacilli are a large group that are divided into several categories. Enterobacteria include many species that cause food poisoning in humans such as Salmonella, Shigella, Proteus and the bacteria Yersinia pestis that is a plague bacteria. There is also a bacteria group called Vibrio that contain bacteria shaped more like commas than rods and the bug that is responsible for cholera is also in the Vibrio group. Helicobacter pylori is also a gram negative bacillus, this bacteria has been identified for the last 25 years as the major cause of stomach ulcers. There are other gram negative bacteria such as Haemophila influenzae, Bordetella pertussis, and Brucella bacteria.
To the left is a picture of Helicobacter pylori which is the main cause of stomach ulcers