Question: how do bacteria communicate ?

Katie Fala answered on 12 Nov 2019:

Thanks for your question! Generally speaking, bacteria communicate with other bacteria using chemical signals. These are very small molecules made by each bacterial cell in the population. When there are low levels of the chemical it means that the population is very small and the bacteria tend to hide and survive, on the other hand when there are very high levels of the chemical it means that their population has become quite large, enough to overwhelm the human immune system for example, and they may change their collective behaviour to cause disease or make biofilms.