What is the main feature of an opportunistic infection?

Question

Quizplus · Accepted Answer

We have many microorganisms that are on or in our bodies and do not cause an infection because our immune systems are able to keep their numbers low and prevent them from moving beyond their normal body location.For example,we all have E.coli in our intestinal tracts and this does not cause us harm as long as our immune systems are working well.Even if a few E.coli leave the intestinal tract and enter the blood or the urine,they usually do not cause an infection because our immune systems get rid of these organisms when they are located where they do not belong.However,a person with a suppressed or weak immune system may not be able to remove or destroy these organisms when they are located outside of the intestinal tract and an infection develops.This is called an opportunistic infection because the organism is taking advantage of the host's weakened immune system and using the opportunity to grow elsewhere in the body.

What Is the Main Feature of an Opportunistic Infection