Question 1

Which of the following is NOT a factor that discourages microbial growth on the skin?

Accepted Answer

Abundant moisture from perspiration

Question 2

Which of the following best describes the difference between an exanthem and an enanthem?

Accepted Answer

Exanthem is a rash on the skin; enanthem is a rash on mucous membranes.

Question 3

Which of the following is a defining characteristic of Staphylococcus aureus compared to Staphylococcus epidermidis?

Accepted Answer

S. aureus is coagulase-positive

Question 4

A patient presents with a rapidly spreading, painful infection of the fascia with tissue necrosis. Which organism is most likely responsible, and what is the key virulence factor?

Accepted Answer

Streptococcus pyogenes; exotoxin B

Question 5

Which of the following best explains why Pseudomonas aeruginosa infections are difficult to treat?

Accepted Answer

It forms biofilms and is highly antibiotic-resistant.

Question 6

Which of the following is the correct sequence of events in the development of inflammatory (moderate) acne?

Accepted Answer

Sebum accumulation → colonization by Cutibacterium acnes → inflammation

Question 7

Which of the following is a function of the M protein in Streptococcus pyogenes?

Accepted Answer

Facilitates attachment and resists phagocytosis

Question 8

A child presents with crusty sores around the nose and mouth that resolve without scarring. Which condition is most likely?

Accepted Answer

Nonbullous impetigo

Question 9

Which of the following best describes the role of normal skin microbiota?

Accepted Answer

They prevent colonization by pathogens and can become opportunistic pathogens.

Question 10

Which of the following is a common causative agent of 'swimmer’s ear' (otitis externa)?

Accepted Answer

Pseudomonas aeruginosa

Question 11

Which of the following statements about the skin’s physical and chemical defenses is CORRECT?

Accepted Answer

The skin’s acidic pH and high salt content inhibit many microbes.

Question 12

Which of the following is the best explanation for why tears help protect the eyes from infection?

Accepted Answer

Tears contain lysozyme, which destroys the cell walls of Gram-positive bacteria.

Question 13

A patient develops a hard, round, deep inflammation with pus and fever after a furuncle is not walled off by the body. What is this condition called?

Accepted Answer

Carbuncle

Question 14

Which of the following is TRUE regarding the treatment of necrotizing fasciitis?

Accepted Answer

Broad-spectrum antibiotics are prescribed because multiple bacterial pathogens may be present.

Question 15

Which of the following is a distinguishing feature of bullous impetigo compared to nonbullous impetigo?

Accepted Answer

Bullous impetigo is caused by exfoliative toxin A and presents with large, easily ruptured blisters.

Question 16

Which of the following best describes the composition of pus?

Accepted Answer

Dead white blood cells, bacteria, tissue debris, and serum

Question 17

Which of the following is a common treatment for comedonal (mild) acne?

Accepted Answer

Topical retinoids such as tretinoin

Question 18

Which of the following is a plausible reason why S. aureus can evade the immune system?

Accepted Answer

It secretes leukocidin and resists opsonization.

Question 19

Which of the following is a characteristic of the normal skin microbiota?

Accepted Answer

Mostly Gram-positive, salt-tolerant, and dry-resistant bacteria

Question 20

Which of the following is a superantigen produced by Staphylococcus aureus that can cause toxic shock syndrome?

Accepted Answer

TSST-1 (toxic shock syndrome toxin 1)

Microbial Diseases of the Skin and Eyes: Structure, Defenses, and Pathogenesis

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