What is overgrowth of commensalism flora?

Natural event: This wording is often used to describe what happens when you take an antibiotic.The antibiotic will kill off the germs in the body compartments that are sensitive to it. But this will leave room for the other germs that are in that space (throat, gut, skin) to grow into the areas left by the dead germs.The term overgrowth reflects the idea that a specific germ is found in an increased proporrtion.