Under Which Circumstances May the Body's Normal Flora Cause Infection

Under which circumstances may the body's normal flora cause infection? (Select all that apply.)

A) When normal flora are present in greater amounts than normal
B) When normal flora are within immunocompromised persons
C) When normal flora present in an unusual place in the body
D) When normal flora are exposed to probiotics
E) When normal flora are exposed to antibiotics
F) When normal flora undergo genetic mutations