Which of the following is true regarding tropism?
a. It is the preference of a pathogen for a given tissue.
b. It is constant for a given microbe.
c. It limits a pathogen to infecting only one host.
d. It is determined by portal of entry.
e. It is independent of host factors.

Indicate the true statements and then correct the false statements so that they are true.

a. HIV is transmitted by a parenteral route.

b. Candida albicans is an opportunistic pathogen that can cause disease in an immune-competent host if the normal microbiota are disrupted.

c. Gram-positive bacteria may produce endotoxin.

d. Siderophores help pathogens obtain calcium.

e. Emerging pathogens tend to exhibit expanded tropism.

f. The more toxic a substance is, the higher its LD₅₀.

g. Virulence is the ability of a microbe to cause disease.

h. Gram-negative bacteria may produce exotoxins.

Pili, fimbriae, and sialic acid binding factors are examples of ________, which are virulence factors that allow pathogens to ________ host tissues––an essential early step in pathogenesis. In contrast, flagella, collagenases, and coagulases tend to act as ________, which help pathogens spread deeper into host tissues.

Assume your patient has a superantigen circulating in their blood. Select the single statement that is most likely to apply to your patient.

a. They are at risk for endotoxic shock.

b. They are not up to date on their vaccinations.

c. They are infected with a Gram-positive microbe.

d. They do not have a fever.

e. They have a viral infection.

Select the false statement about normal microbiota.

a. They compete with pathogens.

b. They do not include potential pathogens.

c. They make vitamins for the host.

d. They train the immune system.

e. A disruption in their balance can lead to disease.

Define the class of each listed exotoxin as type I, II, or III:

a. Superantigen

b. Hemolysins

c. Staphylococcus aureus enterotoxins that cause food poisoning

d. AB toxin

e. Membrane-damaging toxins

f. Phospholipases

Which of the following is a true statement?

a. If a pathogen establishes an infection, it is described as virulent.

b. Pathogenicity is the extent of disease caused by a microbe.

c. Normal microbiota are not usually affected by host factors.

d. A pathogen’s virulence factors change over time in response to selective pressures.

e. Attenuated pathogens cause disease in a normal host.