Deck 17: Skin and Eye Infections

Question 1

Cultures taken from an impetigo lesion reveal bacteria that are Gram- positive cocci which are catalase- and coagulase- negative and cause beta- hemolysis when cultured on blood agar. The responsible species is

A) Staphylococcus aureus.
B) Streptococcus pyogenes.
C) staphylococci species other than Staphylococcus aureus.
D) Pseudomonas aeruginosa.
E) Clostridium perfringens.

Answer 1

Streptococcus pyogenes.

Question 2

Which factor may influence the specific types of microbes found on the skin?

A) moisture levels
B) hormones
C) hormones, moisture levels, and soap and cosmetics usage
D) moisture levels and soap and cosmetics usage
E) soap and cosmetics usage

Answer 2

hormones, moisture levels, and soap and cosmetics usage

Question 3

Why is perspiration an effective defense against microorganisms?

A) basic pH and low salt content
B) low salt content
C) basic pH, low salt content, and presence of lysozyme
D) presence of lysozyme
E) basic pH

Answer 3

presence of lysozyme

Question 4

Which virus results in shingles when it is reactivated with peripheral nerves?

A) variola major
B) varicella- zoster
C) HSV- 1
D) rubella
E) rubeola

Question 5

Which statement is not true about viral warts?

A) Papillomaviruses are the cause of many warts.
B) Warts can be removed but may return later.
C) Plantar warts are found on the feet.
D) Warts can spread from one part of the body to another via autoinoculation.
E) Warts result from abnormal cell growth and so are highly likely to become cancerous.

Question 6

The presence of , a waterproofing protein, in epidermis prevents many microorganisms from gaining access to the body.

A) melanin
B) antibiotics
C) keratin
D) lysozyme
E) sebum

Question 7

A distinctive red rash on the cheeks with an otherwise mild illness is most likely

A) fifth disease.
B) measles.
C) roseola.
D) chickenpox.
E) rubella.

Question 8

What role do capsules and protein A play as virulence factors of Staphylococcus aureus?

A) protect the bacterium from neutrophils
B) protect the bacterium from phagocytosis
C) form blood clots
D) lyse red blood cells
E) break down blood clots

Question 9

You are a nurse serving as a medical volunteer in a refugee camp. Due to extreme poverty, political instability, and displacement, most individuals at the camp have not received any preventative medical care, including vaccinations. While providing care to a young woman in about the fourth month of pregnancy, she mentions that several children, including her toddler, suffered from a mild illness last month. Her toddler had a low fever, a runny nose, and a rash that started on his face then moved downward. The illness resolved quickly in all the children. What illness might the children have had and why should you be concerned?

A) measles; the children may be more susceptible to other infections
B) rubella; the unborn child of the exposed mother may be stillborn or suffer from birth defects
C) hand, foot, and mouth disease; the virus may re- activate at a later time
D) rubella; it is a mild, self- limiting disease so there are no further concerns
E) measles; the child may develop shingles at a later time

Question 10

Which factor, beginning in 1995, is responsible for the decline in chicken pox from a routine childhood disease to a rare infection?

A) natural evolution of the virus to a less virulent form
B) ecological changes affecting the natural reservoir of the virus
C) routine vaccination
D) changes in global migration patterns
E) development of effective anti- viral medications

Question 11

Which virulence factor of Group A streptococci (GAS) is responsible for the rapid spread of tissue death in necrotizing fasciitis?

A) coagulase and hyaluronidase
B) streptokinase
C) hyaluronidase and streptokinase
D) coagulase
E) hyaluronidase

Question 12

Which primary skin lesion is incorrectly matched with its description?

A) Pustule: Raised lesion with pus below the surface
B) Macule: Flat, discolored area of the skin
C) Papule: Sore of irregular size and shape that results as epidermal and dermal skin layers are destroyed
D) Vesicle: Elevated lesion with clear fluid
E) Cyst: Closed fluid- filled sac deep in skin

Question 13

Which staphylococcal infection is not correctly matched with its description?

A) Folliculitis: Swollen, red, pus- filled hair follicles
B) Cellulitis: Deep infection of the lower dermal and subcutaneous fat
C) Erysipelas: A milder form of impetigo with only localized inflammation and mild pain
D) Scalded skin syndrome: Caused by the production of an exfoliative toxin
E) Impetigo: Presence of pus- filled vesicles on the face, lips, or extremities, usually in children

Question 14

These two secondary lesions arise when bleeding or burst capillaries occur in the skin.

A) petechiae and purpura
B) bullae and vesicles
C) cysts and ulcers
D) papular and maculopapular rashes
E) crust and scale

Question 15

Which statement describes an important similarity between chickenpox and smallpox?

A) Vaccinations against both are recommended for all children.
B) Both have a similar mortality rate of about 30%.
C) Both involve the formation of a vesicular rash.
D) Both are caused by viruses which lie dormant in nerve cells and be reactivated later in life.
E) Both are treatable with antiviral therapy.

Question 16

Which factor is not a reason Propionibacterium acnes (P. acnes) is often associated with acne?

A) increased oxygen levels in clogged pores favoring bacterial growth
B) biofilm formation by P. acnes in pores and glands
C) increased sebum production during adolescence
D) the inflammatory responses to P. acnes which causes pustules and cysts
E) the ability of P. acnes to metabolize sebum

Question 17

Which is not a specific cause of reactivation of HSV- 1?

A) hormonal changes
B) menstruation
C) ultraviolet radiation
D) having a cold or fever
E) stress

Question 18

In streptococcal toxic shock syndrome, pathology results from toxins in the bloodstream which may cause both a red skin rash, as well as

A) release of foul- smelling gases from the infection site.
B) a decrease in blood pressure leading to organ failure.
C) formation of a blue- or green- colored pus.
D) degradation of connective tissue.
E) peeling away of the epidermal layer of skin.

Question 19

A parent calls the pediatrician's office about uncomfortable sores on the inside of her child's mouth. You suspect hand, foot, and mouth disease (HFMD), but need to rule out measles. Which information could help you to rule out measles?

A) other symptoms of illness such as fever and sore throat
B) presence of a rash on the face, trunk, and extremities
C) vaccination history, other symptoms of illness such as fever and sore throat, and presence of a rash on the face, trunk, and extremities
D) vaccination history and other symptoms of illness such as fever and sore throat
E) vaccination history

Question 20

A maculopapular rash is characteristic of

A) warts.
B) measles and chickenpox.
C) measles.
D) chickenpox and warts.
E) chickenpox.

Question 21

Tissue necrosis caused by Clostridium perfringens may be distinguished from necrotizing fasciitis in what way?

A) presence of Gram- positive, endospore forming bacilli in the affected area
B) presence of Gram- positive, catalase- negative cocci in the affected area
C) emission of foul- smelling gases from the damaged tissue and presence of Gram- positive, catalase- negative cocci in the affected area
D) emission of foul- smelling gases from the damaged tissue
E) presence of Gram- positive, endospore forming bacilli in the affected area and emission of foul- smelling gases from the damaged tissue

Question 22

A contributing factor to cutaneous candidiasis might be

A) a shift in normal microbiota.
B) hyperactive immune function.
C) a shift in normal microbiota and hyperactive immune function.
D) dry, exposed skin and hyperactive immune function.
E) dry, exposed skin.

Question 23

Cutaneous mycoses usually

A) are superficial infections on the skin, hair, or nails.
B) are not associated with changes in the normal microbiota.
C) are invasive with a considerable risk of fatality.
D) occur in the deeper dermal layers or in muscles.
E) respond quickly to treatment with a single dose of topical antifungal medication.

Question 24

Which of the following skin infections is caused by a protozoan?

A) otitis externa
B) cutaneous anthrax
C) cutaneous candidiasis
D) leishmaniasis
E) dermatophytic infections

Question 25

What type of infection is shown?

A) candidiasis
B) subcutaneous mycoses
C) tinea
D) impetigo
E) leishmaniasis

Question 26

The numbers and types of microbes found in the normal skin microbiota are consistent across all body surfaces.

Question 27

As measles vaccination rates have declined in recent years due to concerns about the vaccine, there have been no documented outbreaks of the disease, showing that the measles virus has been successfully eliminated from the population.

Question 28

A hospital burn unit has experienced ongoing problems with pseudomonad infections in multiple wards despite attention to patient hygiene and environmental sanitation. Which of the following would not be a possible source of the bacteria?

A) patient room cleaning supplies
B) skin microbiota of staff
C) hospital floral shop
D) hospital cafeteria
E) therapy pool in the physical therapy department

Question 29

Which statement is not true about leishmaniasis?

A) It is transmitted by sand flies.
B) It is a slow infection that can persist for months to years.
C) Over twenty different Leishmania species may cause leishmaniasis.
D) It is preventable by a vaccine which is recommended for travelers to endemic areas.
E) It is most prevalent in the tropics and subtropics.

Question 30

A small child presents to the pediatric office with a reddened sclera, itchy eyes, and a watery, clear discharge from the affected eye. The most likely diagnosis is

A) bacterial conjunctivitis.
B) viral conjunctivitis.
C) trachoma.
D) either bacterial conjunctivitis or trachoma; further tests are needed.
E) cannot be distinguished between bacterial or viral conjunctivitis so antibiotic treatment is given regardless.

Question 31

Which does not apply to ringworm infections?

A) caused by a worm
B) caused by members of the normal skin biota
C) can be acquired by direct or indirect contact
D) may occur on the feet, groin, scalp, nails, or body
E) may manifest as a round skin lesion with a scaly red margin

Question 32

Methicillin- resistant Staphylococcus aureus (MRSA) cause the same infections as non- resistant S. aureus stains; however, the bacterium has evolved cell- wall building enzymes which do not bind with methicillin and other beta- lactam antibiotics.

Question 33

The common infection known as "pink eye" is an infection of the

A) cornea.
B) retina.
C) conjunctiva.
D) iris.
E) sclera.

Question 34

Several forms of keratitis are linked to

A) day care centers.
B) re- activation of a herpes virus infection.
C) hospitals or other healthcare settings.
D) vertical transmission during childbirth.
E) improper handling of contact lenses.

Question 35

Which patient group is least susceptible to infections by pseudomonads?

A) otherwise healthy mothers in childbirth
B) organ transplant recipients on immunosuppressive drugs
C) burn patients
D) competitive swimmers who train daily
E) cystic fibrosis patients

Question 36

Even though rubella is a mild, self- limiting disease, vaccination remains important to prevent severe neurological damage to babies whose mothers are exposed to rubella in utero.

Question 37

Which protective mechanism of the eye is incorrectly matched with its description?

A) Lacrimal gland: Produces tears
B) Lysozyme: Breaks down bacterial cell walls
C) Tears: Washes away microbes and contains antimicrobial chemicals
D) Lactoferrin: Binds up free iron which some microbes require
E) Conjunctiva: Transparent layer which protects the iris

Question 38

While on a medical volunteer trip to an impoverished country, you encounter a patient whose eyelids are turned inward as shown. What is the cause and the best treatment?

A) neonatal bacterial conjunctivitis; antibiotic or silver drops should have been given at birth
B) onchocerciasis (river blindness); doxycycline
C) viral conjunctivitis; no treatment but the condition will resolve with time
D) Acanthamoeba; corneal transplant will likely be necessary
E) trachoma; single dose of oral azithromycin

Question 39

Pyocyanin, a greenish- blue pigment produced by pseudomonads, acts as a virulence factor by

A) generating reactive oxygen species.
B) breaking down reactive oxygen species.
C) lysing red blood cells.
D) digesting lipids in tissues.
E) forming a biofilm.

Question 40

Onchocerciasis, or river blindness, is caused by a and is spread via .

A) virus; fomites such as towels or bedding
B) helminth; blackflies
C) bacterium; gnats which swarm near the eye
D) protozoan; contaminated water
E) fungus; contaminated contact lens solution

Question 41

Describe and contrast three types of bacterial skin infections that can lead to tissue necrosis and death. Name and characterize the causative bacteria, and describe epidemiological and clinical features of each disease.

Question 42

The eyes lack a protective normal microbiota.

Question 43

Most fungal skin infections are likely to remain superficial except in individuals who are immunocompromised.

Question 44

Keratitis is an inflammation of the cornea and can be caused by members of all microbial groups except viruses.

Question 45

Describe the causative agent, epidemiology, presentation, and treatment for 3 causes of infectious blindness.

Question 46

Describe how latency contributes to the infection process of the Varicella- Zoster and Herpes simplex- 1 viruses.

Question 47

Because pseudomonads are widespread in the environment and are versatile in their metabolic capabilities, skin infections with these bacteria are common even in healthy people with no skin breaches.