Microbiologists are fond of saying that only a tiny minority of bacteria cause disease. Are there reasons for thinking this might not be true? In what sense are bacteria life givers rather than life...

Microbiologists are fond of saying that only a tiny minority of bacteria cause disease. Are there reasons for thinking this might not be true?

In what sense are bacteria life givers rather than life takers? Is it possible that disease-causing bacteria might have a beneficial role in another context or even in their relationship with the human body?