A)the pathogen establishes itself in a body site without causing infection.
B)the pathogen can be removed by regular soap washing.
C)the pathogen causes an immune response.
D)there is visible inflammation at the site.
E)none of the above are correct because pathogens only infect and never colonise.

A)The composition of the intestinal microbiota never changes.
B)Stomach acid stimulates the growth of pathogenic microorganisms.
C)Intestinal bacteria are always aerobic.
D)All intestinal bacteria are potentially harmful.
E)None of the above.

A)are found only on hospitalised patients.
B)normally inhabit parts of the human body.
C)normally exist in the environment.
D)are found only on human skin.
E)never cause disease.