Question 1

Which of the following is NOT a protective quality of the skin that helps prevent bacterial invasion?

Accepted Answer

High moisture content on the skin surface

Question 2

A patient presents with a painful, fluid-filled lesion larger than 1 cm in diameter on their arm. Which term best describes this lesion?

Accepted Answer

Bulla

Question 3

Which of the following is a pathogenicity factor produced by Staphylococcus aureus that allows it to evade the immune system and cause disease?

Accepted Answer

Coagulase

Question 4

A burn patient develops a blue-green pus at the wound site. Which organism is most likely responsible, and what is the pigment called?

Accepted Answer

Pseudomonas aeruginosa; pyocyanin

Question 5

Which of the following best describes the difference between cutaneous and subcutaneous mycoses?

Accepted Answer

Cutaneous mycoses affect the outer skin, hair, and nails; subcutaneous mycoses penetrate deeper tissues.

Question 6

A child presents with a mild rash and their mother is pregnant. Which viral infection is most concerning due to the risk of fetal defects?

Accepted Answer

Rubella

Question 7

Which of the following is the most common skin disease in humans, and what is its causative agent?

Accepted Answer

Acne; Cutibacterium acnes

Question 8

A newborn develops severe conjunctivitis after birth. Which organism is most likely responsible for ophthalmia neonatorum?

Accepted Answer

Neisseria gonorrhoeae

Question 9

Which of the following is a correct pairing of disease and its causative agent?

Accepted Answer

Scabies; Sarcoptes scabiei

Question 10

A patient presents with a rapidly spreading, red, swollen area on the leg, and laboratory tests reveal Streptococcus pyogenes. Which pathogenicity factor is most responsible for the tissue destruction observed?

Accepted Answer

Hyaluronidase

Question 11

Which of the following best explains why Pseudomonas aeruginosa is a common cause of infection in cystic fibrosis patients?

Accepted Answer

It forms biofilms and is highly resistant to antibiotics.

Question 12

A patient with a history of chickenpox develops a painful, localized rash years later. What is the most likely diagnosis and causative agent?

Accepted Answer

Shingles; Herpesvirus varicella-zoster

Question 13

Which of the following is the leading cause of blindness worldwide, and what is its causative agent?

Accepted Answer

Trachoma; Chlamydia trachomatis

Question 14

A patient presents with a ring-shaped, scaly lesion on the arm. Which type of mycosis is this, and what is a likely causative agent?

Accepted Answer

Cutaneous mycosis; Trichophyton spp.

Question 15

Which of the following best describes the role of lysozyme in skin and mucous membrane defense?

Accepted Answer

It breaks down bacterial cell walls.

Question 16

A patient develops a rapidly progressing infection after a minor cut, with severe tissue destruction. Laboratory results show Streptococcus pyogenes. Which combination of pathogenicity factors most likely contributed to the severity?

Accepted Answer

Hyaluronidase and streptokinase

Question 17

Which of the following is a correct match between a disease, its causative agent, and its mode of transmission?

Accepted Answer

Chickenpox; Herpesvirus varicella-zoster; respiratory route

Question 18

A patient presents with itching and visible nits in their hair. What is the most likely diagnosis and recommended treatment?

Accepted Answer

Pediculosis; permethrin or pyrethrin

Question 19

Which of the following best explains why normal skin microbiota are typically resistant to drying and high salt concentrations?

Accepted Answer

They are primarily gram-positive cocci such as staphylococci and micrococci.

Question 20

A gardener develops a chronic, ulcerating lesion on the hand after a thorn prick. Which organism is most likely responsible, and what type of mycosis is this?

Accepted Answer

Sporothrix schenckii; subcutaneous mycosis

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

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