Deck 22: Skin Infections

Question 1

The member of the normal microbiota sometimes considered responsible for tinea versicolor is

A)staphylococci.
B)diptheroids.
C)Candida spp.
D)Malassezia spp.

Answer 1

Malassezia spp.

Question 2

Which of the following may be added to normal media to make it more selective for staphylococci?

A)7.5% salt
B)0.5% HCl
C)1.0% glucose
D)5.0% mannose

Answer 2

7.5% salt

Question 3

The principal species of Staphylococcus found on the skin is

A)aureus.
B)acnes.
C)pyogenes.
D)epidermidis.

Answer 3

epidermidis.

Question 4

The antimicrobial aspect(s)of the skin is/are

A)dryness.
B)saltiness.
C)acidity.
D)toxicity.
E)All of the choices are correct.

Question 5

The bacteria that appear to maintain balance between the members of the normal microbiota and play a vital role in limiting colonization by pathogens are

A)staphylococci.
B)diptheroids.
C)Candida spp.
D)Malassezia spp.

Question 6

Which of the following organisms is not normally found on the skin?

A)Staphylococci
B)Diptheroids
C)Candida spp.
D)Malassezia spp.

Question 7

Which is deemed the most serious staphylococcal skin infection?

A)Tinea versicolor
B)Folliculitis
C)Furuncles
D)Carbuncles

Question 8

The oily secretion that lubricates the hair follicles of the skin is

A)sebum.
B)eczema.
C)suder.
D)acne.

Question 9

Which of the following is considered a function of the skin?

A)Regulation of body temperature
B)Prevention of fluid loss
C)Synthesis of vitamin D
D)Produces cytokines
E)All of the choices are correct.

Question 10

Which of the following is a fairly reliable method of characterizing strains of S.aureus?

A)Complement fixation
B)Protein fingerprint
C)Genome typing
D)LPS pattern

Question 11

Diphtheroids

A)are part of the normal microbiota of the skin.
B)are responsible for body odor.
C)include P.acnes.
D)include Malassezia spp.
E)are part of the normal microbiota of the skin,are responsible for body odor,AND include P.acnes.

Question 12

The surface layer of the skin is the

A)cutaneous.
B)keratin.
C)dermis.
D)epidermis.

Question 13

The secretions of the sweat and sebaceous glands provide ________ to the microbiota.

A)water
B)amino acids
C)lipids
D)All of the choices are correct.

Question 14

The Rickettsial disease that killed Howard Ricketts and Stanislaus Prowazek was

A)louse-borne typhus.
B)tick-borne typhus.
C)yellow fever.
D)bubonic plague.

Question 15

The growth of P.acnes within hair follicles,in many individuals,leads to

A)eczema.
B)carbuncles.
C)boils.
D)acne.

Question 16

Which of the following may aid Staphylococcus in resisting phagocytosis?

A)Leukocidin
B)Hemolysin
C)Granulation enzyme
D)Coagulase

Question 17

The preferred habitat of S.aureus is the

A)throat.
B)urethra.
C)bladder.
D)nasal chamber.

Question 18

Which of the following normal skin microbiota is a small yeast?

A)Staphylococci
B)Diphtheroids
C)Candida spp.
D)Malassezia spp.

Question 19

Which of the following is considered an important function of the skin?

A)Hold muscle to bone
B)Manufacture blood cells
C)Produce antibodies
D)Control body temperature

Question 20

A protein associated with a more virulent form of Staphylococcus is

A)leukocidin.
B)mannose.
C)streptokinase.
D)coagulase.

Question 21

In which of the following does a rash start on the palms and soles and progress toward the trunk?

A)Epidemic typhus
B)Typhoid
C)Lyme disease
D)Impetigo
E)Rocky Mountain spotted fever

Question 22

The preferred host of Ixodes scapularis is the

A)wood rat.
B)white-footed mouse.
C)moose.
D)human.

Question 23

Which of the following virulence factors used by Staphylococcus puts holes in host cells?

A)Protein A
B)Alpha toxin
C)Leukocidin
D)Clumping factor

Question 24

The S.aureus product that causes scalded skin syndrome is/are

A)exfoliation toxin.
B)lipases.
C)leukocidins.
D)protein M.
E)All of the choices are correct.

Question 25

In S.pyogenes,which of the following interferes with phagocytosis?

A)M protein
B)Protein A
C)Collagen
D)Pilin

Question 26

The major vector of Rocky Mountain spotted fever in the western United States is

A)Rickettsia rickettsi.
B)Rickettsia prowazeki.
C)Borrelia burgdorferi.
D)Dermacentor andersoni.

Question 27

The most important vector of Lyme disease in the eastern United States is

A)Dermacentor virabilis.
B)Dermacentor andersoni.
C)Staphylococcus aureus.
D)Ixodes scapularis.

Question 28

The unique characteristic of Lyme disease is

A)erythema migrans.
B)induration.
C)carbuncle.
D)furuncle.

Question 29

Which is true of MRSA strains?

A)They are all resistant to vancomycin.
B)They carry the R plasmid.
C)They may be susceptible to linezolid.
D)The carry the R plasmid AND they may be susceptible to linezolid.

Question 30

A frequent complication of scalded skin syndrome is a secondary infection caused by

A)M.luteus.
B)S.pyogenes.
C)S.epidermidis.
D)Pseudomonas spp.

Question 31

After being bitten by an infected tick,transfer of the rickettsial organism occurs

A)immediately.
B)within 5 minutes.
C)within 20 minutes.
D)within 4-10 hours.

Question 32

In addition to S.aureus,impetigo may also involve

A)M.luteus.
B)S.pyogenes.
C)S.epidermidis.
D)Pseudomonas spp.

Question 33

Rocky Mountain spotted fever is an example of a(n)

A)animalosis.
B)tickonosis.
C)plantonosis.
D)zoonosis.

Question 34

Which of the following is an obligate intracellular parasite?

A)M.luteus
B)S.pyogenes
C)Rickettsia rickettsi
D)Pseudomonas spp.

Question 35

Which of the following pertains to Borrelia burgdorferi?

A)Coccus
B)Bacillus
C)Spirochete
D)Filament

Question 36

The growth stage of the vector that is mainly responsible for transmitting Lyme disease is the

A)nymph stage.
B)egg.
C)moulter.
D)adult.

Question 37

Many childhood diseases caused by viral infections of the upper respiratory tract can usually be diagnosed by

A)inspection of the rash.
B)the type of cough.
C)the type of fever.
D)the incubation period.

Question 38

S.aureus clumping factor

A)causes fibrinogen to clump together.
B)causes bacteria to clump together in plasma.
C)reacts with prothrombin.
D)produces staphylothrombin.

Question 39

The causative agent of Lyme disease is

A)Rickettsia rickettsi.
B)Rickettsia prowazeki.
C)Borrelia burgdorferi.
D)Dermacentor andersoni.

Question 40

The stage of Lyme disease that is characterized by arthritis is the

A)primary.
B)third.
C)second.
D)fourth.

Question 41

Borrelia burgdorferi is a spirochete with a number of axial filaments.

Question 42

An important diagnostic sign of measles is

A)Koplik's spots.
B)giant cells.
C)fever.
D)swollen lymph nodes.

Question 43

Reactivation of chickenpox is called

A)shingles.
B)herpes zoster.
C)pneumonia.
D)exanthems.
E)shingles AND herpes zoster.

Question 44

Varicella is a member of the herpes family of viruses and produces a latent infection.

Question 45

The childhood disease that damages the body defenses and is frequently complicated by secondary infections involving,primarily,Gram-positive cocci is

A)German measles.
B)measles.
C)mumps.
D)chickenpox.

Question 46

The MMR vaccine is used to protect against

A)mononucleosis,mange,rubeola.
B)measles,mange,rubeola.
C)mononucleosis,mumps,rubella.
D)measles,mumps,rubella.

Question 47

The most serious consequence of rubella is

A)encephalitis.
B)meningitis.
C)deafness.
D)birth defects.

Question 48

A common viral rash of childhood with the popular name chickenpox is also known as

A)bariola.
B)rubella.
C)rubeola.
D)varicella.

Question 49

The rubeola virus contains

A)double-stranded RNA.
B)single-stranded DNA.
C)double-stranded DNA.
D)single-stranded RNA.

Question 50

Warts are caused by

A)papillomavirus.
B)parvovirus.
C)adenoviruses.
D)herpes virus.

Question 51

The skin-invading molds belong to the genera

A)Epidermophyton.
B)Microsporum.
C)Trichophyton.
D)Ixodes.
E)Epidermophyton,Microsporum,AND Trichophyton.

Question 52

Coagulase-positive S.aureus is often involved in disease.

Question 53

Chickenpox and measles are both acquired by the respiratory route.

Question 54

Diseases caused by fungi are called mycoses.

Question 55

Complications of measles may include pneumonia and encephalitis.

Question 56

The MMR vaccine is used to protect against measles,mumps,and rubella.

Question 57

The varicella virus is a member of which virus family?

A)Paramyxo
B)Toga
C)Papilloma
D)Herpes

Question 58

Humans are the only reservoir for varicella-zoster.

Question 59

Rubella is a member of which virus family?

A)Paramyxo virus
B)Herpes
C)Togavirus
D)Papovavirus

Question 60

Rubella,rubeola,and varicella-zoster are all only acquired via

A)the gastrointestinal route.
B)the respiratory route.
C)wounds.
D)blood transfusions.

Question 61

What is the epidemiological significance of shingles?

A)It shows that,as a latent viral infection,there is always a possible reservoir available to reinfect new susceptible individuals.
B)It shows that we must always be vigilant against this deadly and highly infectious secondary infection in elderly and immunocompromised individuals.
C)It shows that,as a chronic viral infection,individuals infected are always infectious to others around them,even when they do not show outward symptoms.
D)It shows that our fight for long-term eradication of varicella zoster virus will be a very long fight,depending on immunizing all newly born individuals until all the people who had ever had contracted the illness have died
E)It shows that,as a latent viral infection,there is always a possible reservoir available to reinfect new susceptible individuals AND it shows that our fight for long-term eradication of varicella zoster virus will be a very long fight,depending on immunizing all newly born individuals until all the people who had ever contracted the illness have died.

Question 62

The existence of extensive scalded skin syndrome does not indicate that Staphylococcus is growing in all the affected areas.Why not?

A)This condition is caused by an exotoxin produced by certain strains of this microbe,and NOT directly by the microbe itself.
B)This condition is caused by an endotoxin produced by certain strains of this microbe,and NOT directly by the microbe itself.
C)This condition isn't caused by Staphylococcus at all.
D)This microbe doesn't grow in the skin-but the toxins it releases are transported by the blood vessels into the skin,where it achieves the observed effect.

Question 63

The skin-invading molds are collectively called dermatophytes.

Question 64

A public health official was asked to speak about immunizations during a civic group luncheon.One parent asked if rubella was still a problem.In answering the question,the official cautioned women planning to have another child to have their present children immunized against rubella.Why did the official make this statement to the group?

A)Rubella is spread very easily by respiratory secretions and is largely asymptomatic.However,it can cause birth defects/stillbirth in pregnant women.Women with other children would want to prevent these children from acquiring the virus before attempting to conceive a new child in order to protect the fetus.
B)Rubella is passed very easily between children,so the official was trying to protect the child that would soon be born from this infection that might be brought in by its siblings after it was born.
C)The official is getting kickbacks and bribes from the companies making the vaccines,and he's trying to pad his pockets by getting as many people immunized as possible,regardless of whether they need it or not.
D)Rubella infections often lead to very serious and potentially fatal complications.While a woman is pregnant,she may not be able to take care of a sick child as easily.The vaccine will prevent the child already in the family from falling ill and potentially dying due to these possible complications.

Question 65

When Lyme disease was first being investigated,the observation that frequently only one person in a household was infected was a clue leading to the discovery that the disease was spread by arthropod bites.Why was this so?

A)Mosquitoes (an example of arthropods)are never inside a house.They are strictly outdoor animals,so they couldn't spread the infection inside the household.
B)Mosquitoes (an example of arthropods)only bite once in their life cycle.As such,they can only transmit the illness once before they die.Even if an infected mosquito was inside a house,it could therefore only infect one human.
C)If the infection is spread by the bite of an arthropod,it wouldn't spread easily by respiratory secretions,direct contact,or sexual contact between individuals within the family.
D)Arthropods lose their mechanical ability to bite a human after a single bite,much like certain bees that lose their stinger after a single sting.This prevents them from transmitting the infection to more than one individual in a household.

Question 66

Why is it a good idea to immunize little boys against rubella?

A)As this is a sexually-transmitted disease,vaccinating girls AND boys early in their lives prevents the spread of the disease in adulthood.
B)We want to achieve herd immunity,and there's no reason why only girls would be infected by this virus.By vaccinating the entire population,we achieve a higher degree of herd immunity than is possible by vaccinating only girls.
C)Only boys get this disease,and one of the common complications is sterility.
D)While this disease is quite strikingly symptomatic in girls,it is completely asymptomatic in boys.Boys can be carriers and transmit it easily to girls they are in close proximity to without realizing it through respiratory secretions.This can lead to large-scale and dangerous outbreaks in the female population.

Question 67

Who would have larger numbers of bacteria living on the surface of their skin,a person living in the tropics or in the desert,and why?

A)The tropics would provide more shade,so the surface of the skin wouldn't be exposed to high levels of ultraviolet radiation.This would protect the bacteria on the skin,and they would have higher numbers due to this shading effect.
B)The very low humidity of the desert would lead to rapid evaporation of sweat and sebum from an individual's skin.Bacteria need these secretions for a nutrient source.Without them,bacteria would be found in much lower numbers on the skin of a person in the desert than the skin of the person in the tropics.
C)The constant secretion (and lack of evaporation)of high amounts of sweat would produce a highly salty environment on the skin of a person in the tropics.This would provide a local environment that would be too hostile for microbes to survive,so the number of microbes on the skin of the person in the tropics would be lower than that of the person in the desert.
D)The constant secretion of large amounts of sweat would wash bacteria off of the skin of the person in the tropics.As such,the person in the desert should have much more bacteria on their skin than the person in the tropics would.