Opportunistic infections. How is it that some microbe (say a bacteria) that has no virulence factors and doesn’t cause disease in a healthy individual all of the sudden do when said individual’s immune system is weak?

Question

Opportunistic infections. How is it that some microbe (say a bacteria) that has no virulence factors and doesn’t cause disease in a healthy individual all of the sudden do when said individual’s immune system is weak?

In: Biology

Answer 1

Opportunistic infections often occur when all the nkrmal bacteria in your body is depleted. For example if you take an antibiotic, the antibiotic will target all bacteria. This includes normal flora (microbes are always in your body).

However, antibiotics wont kill all your bacteria. And since the normal flora from your body is gone, the opportunistic bacteria has no competition so it is able to outgrow your normal defenses.