Question

Which of the following are ways in which the normal flora protects against invasion by pathogens? (mark all that apply)

Select one or more:

a. they produce toxic by-products

b. they produce lysozyme

c. they do not protect against invasion by pathogens

d. they prevent attachment by pathogens

e. they compete for essential nutrients

Answer 1

Answer- correct options are:-

a) they produce toxic by-products

d) they prevent attachment by pathogens

e)  they compete for essential nutrients

-They induce low grade toxemia by producing minute amounts of bacterial toxins in the circulation. These toxins stimulates the formation of natural antibodies.

-They prevent colonization of pathogens by competing for attachment sites or for essential nutrients. For example- in oral cavity, the intestine,etc