But the yoghurt bacteria don't kill the others. They just compete with food, and since we put lots in there, they overrule the odd 'bad one'. Translating this to scientific terminology, you are referring to both bacteria and viruses. First, since bacteria is a type of germ, and there are lots and lots of types of bacteria, the general answer would be bacteria don't kill themselves. Second, involves addressing the role of viruses.
Viruses tend to use cells to make thousands and thousands of copies of themselves.
They use both bacterial cells and cells in your body to do this. Bear in mind, that germs are a natural part of our world. They are everywhere, in the air we breath, on our skin, and in our mouths. Most of the time there aren't enough of them to make us sick, and our immune systems can control them. Argonne National Laboratory, Division of Educational Programs, Harold Myron, Ph.D., Division Director.