How are normal flora originally acquired?

The fetus is surrounded by amniotic fluid of its mother. It acquires the normal flora of its mother. After birth, the newborn begins to acquire its own "normal flora". Humans have normal flora on their skin and in every body throughout life; it is not completely washed away although it can be changed, reduced, or disrupted by medications or changes in Ph or by actions humans take during hygiene or sexual activities. Then micro-oganisms of the normal flora become pathogens that can cause infection.