Question 1

A patient is prescribed amoxicillin for a bacterial infection. Which of the following best describes the mechanism of action of amoxicillin?

Accepted Answer

It disrupts the synthesis of peptidoglycan in bacterial cell walls.

Question 2

Which of the following drugs is most appropriate for treating a viral infection such as herpes simplex, and what is its mechanism of action?

Accepted Answer

Acyclovir; it inhibits viral DNA polymerase.

Question 3

A patient presents with a high eosinophil count. Which of the following is the most likely cause?

Accepted Answer

A parasitic helminth infection

Question 4

Which of the following statements best distinguishes between innate and adaptive immunity?

Accepted Answer

Innate immunity provides immediate, non-specific defense, while adaptive immunity is specific and develops memory.

Question 5

Which antibody class is primarily responsible for the secondary immune response and is the most abundant in serum?

Accepted Answer

IgG

Question 6

A child receives a vaccine containing an inactivated toxin. What type of vaccine is this, and what is the main advantage?

Accepted Answer

Toxoid vaccine; it induces immunity without causing disease.

Question 7

Which of the following best describes the action of polymyxin B?

Accepted Answer

It disrupts the plasma membrane of Gram-negative bacteria.

Question 8

A patient is treated with tetracycline for a broad-spectrum bacterial infection. Which side effect is most commonly associated with this drug?

Accepted Answer

Photosensitivity and discoloration of teeth

Question 9

Which of the following scenarios best illustrates artificial passive immunity?

Accepted Answer

A person receives an injection of pre-formed antibodies after exposure to rabies.

Question 10

Which of the following is a major reason why vaccines are important to a community?

Accepted Answer

They provide herd immunity, protecting those who cannot be vaccinated.

Question 11

Which drug is used to treat helminth infections and what is its mechanism of action?

Accepted Answer

Ivermectin; it paralyzes the worm by enhancing inhibitory neurotransmission.

Question 12

A patient is prescribed chloramphenicol. Which serious side effect should be closely monitored?

Accepted Answer

Aplastic anemia

Question 13

Which of the following best describes the difference between humoral and cellular immunity?

Accepted Answer

Humoral immunity involves antibodies produced by B cells, while cellular immunity involves T cells targeting infected cells.

Question 14

Which of the following drugs is most likely to be effective against a fungal infection and what is its mechanism?

Accepted Answer

Miconazole; it inhibits ergosterol synthesis in fungal cell membranes.

Question 15

A patient is prescribed Tamiflu (oseltamivir) for influenza. What is the drug's mechanism of action?

Accepted Answer

It inhibits viral neuraminidase, preventing viral release from host cells.

Question 16

Which of the following best explains why a secondary immune response is faster and stronger than a primary response?

Accepted Answer

Memory B and T cells are generated during the primary response and respond rapidly upon re-exposure.

Question 17

Which of the following antibiotics is most likely to be effective against both Gram-positive and Gram-negative bacteria?

Accepted Answer

Amoxicillin

Question 18

A patient is prescribed Paxlovid (nirmatrelvir/ritonavir) for COVID-19. What is the mechanism of action of nirmatrelvir?

Accepted Answer

It inhibits the main protease of SARS-CoV-2, preventing viral replication.

Question 19

Which of the following best describes the action of Humira (adalimumab) in the treatment of autoimmune diseases?

Accepted Answer

It is a monoclonal antibody that inhibits tumor necrosis factor-alpha (TNF-α).

Question 20

A patient is prescribed neomycin as part of a topical ointment. What is the primary mechanism of action of neomycin?

Accepted Answer

It inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit.

Clinical Microbiology Exam 3 Study Notes: Immunity, Antimicrobial Drugs, and Vaccines

Study Guide - Practice Questions