Chapter 21 - Microbial Diseases of the Skin and Eyes Flashcards

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1
Q

Staphylococcus Aureus affects the _____.

A

skin

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2
Q

Staphylococcus aureus is gram +/-?

A

positive

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3
Q

S.aureus is coagulase ________ meaning….

A

-positive
-it can produce coagulase

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4
Q

Coagulase

A

-an enzyme that clots fibrin in blood

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5
Q

Staphylococcus epidermis is coagulase _________ meaning….

A

-negative
-it does not produce coagulase

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6
Q

S. epidermidis make up ___% of normal microbiota on the skin

A

90

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7
Q

When is S. epidermidis pathogenic?

A

when the skin barrier is broken or invaded by medical procedures (ie. catheter)

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8
Q

Which staphylococci is the most pathogenic?

A

S. aureus

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9
Q

What is the purpose of the gold pigment in S. aureus?

A

-protects against the antimicrobial effects of sunlight

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10
Q

Enterotoxins

A

-affect GI tract

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11
Q

How does S. aureus invade?

A

-direct invasion, attach to follicle
-stimulates vigorous inflammatory response
-produces toxins that kill phagocytic cells

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12
Q

Where is S. aureus common in humans?

A

nasal passages

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13
Q

Folliculitis

A

-a symptom of S. aureus
-often occur as pimples

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14
Q

Sty

A

-a symptom of S. aureus
-the infected follicle of an eyelash

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15
Q

Furuncle (Boil)

A

-symptom of S. aureus
-more serious hair follicle infection
-pus, red, swollen surrounded by inflamed tissue
-a type of abscess

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16
Q

Carbuncle

A

-development of furuncle of S. aureus
-inflammation of tissue under the skin
-usually has fever

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17
Q

What is the treatment of a carbuncle?

A

-surgery
-penicillin

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18
Q

What bacteria causes impetigo?

A

Staphylococci

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19
Q

What is impetigo?

A

-highly contagious skin infection
-affects children age 2-5
-yellow crusts

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20
Q

Pemphigus Neonatorum

A

impetigo of the newborn

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21
Q

Does impetigo use an exotoxin?

A

no

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22
Q

Impetigo is a __________ meaning…

A

pyoderma; pus in the skin

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23
Q

Scalded Skin Syndrome (SSSS)

A

-redness
-itching
-blisters
-exfoliation, separation of skin layers
-contagious clear fluid filled blisters

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24
Q

What is a big risk of SSSS?

A

secondary infection, SSSS is a great portal of entry for other bacteria

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25
Q

Who is most at risk of SSSS?

A

in children and elderly

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26
Q

How do you treat SSSS?

A

-penicillin
-isolation
-clean fomites

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27
Q

What is the role of the exotoxin in SSSS?

A

-it is exfoliative
-breaks ester bonds between skin cells

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28
Q

Desquamation

A

skin shedding

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29
Q

Exfoliative Toxin A

A

-local
-causes bullous impetigo

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30
Q

Exfoliative Toxin B

A

-circulates
-causes SSSS

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31
Q

What does SSSS stand for?

A

Staphylococcal Scalded Skin Syndrome

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32
Q

Name 3 ways someone can get TSS

A
  1. tampon use
  2. surgical wound
  3. childbirth
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33
Q

Why are tampons such a good medium for bacterial growth?

A

-blood makes them nutrient rich
-abrasive material

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34
Q

Symptoms of TSS

A

-fever
-aches
-nausea
-vomiting
-confusion
-shock (impaired kidney function)
-red skin rash

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35
Q

What can the TSS rash be?

A

SSSS

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36
Q

What is the occurrence of death with with TSS?

A

less than 3%

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37
Q

TSS Toxin 1 and 2

A

-formed at the growth site and circulates in the bloodstream

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38
Q

Why do TSS symptoms result?

A

Super antigenic properties of the toxin

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39
Q

How to prevent TSS?

A

-hand washing
-frequently changing tampons
-using pads or menstrual cups

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40
Q

Streptococci are gram ____ bacteria

A

positive

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41
Q

What do streptococci secrete as they grow?

A

toxins and enzymes

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42
Q

__________ are a toxin released by streptococci?

A

hemolysins; they lyse red blood cells

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43
Q

What two categories are streptococci grouped into?

A

alpha-hemolytic and beta-hemolytic

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44
Q

What is GAS?

A

group A streptococci

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45
Q

How are streptococci grouped by serology?

A

according to antigenic carbohydrates in their cell walls

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46
Q

GAS are synonymous with Streptococcus ________.

A

pyogenes

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47
Q

What kind of hemolytic group is S. pyogenes?

A

beta-hemolytic

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48
Q

Streptolysins

A

-released by S. pyogenes
-lyse red blood cells
-toxic to neutrophils

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49
Q

S. pyogenes has ________ which is…

A

M protein; external to the cell walls prevents the activation and allows the microbe to evade phagocytosis and neutrophils and colonize mucous membranes

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50
Q

Does GAS have a capsule?

A

yes

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51
Q

What does GAS produce?

A

-streptokinases (dissolve blood clots)
-hyaluronidase (cements cells together)
-deoxyribonucleases (degrade DNA)

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52
Q

What is a common infection S. aureus and S. pyogenes cause?

A

Impetigo in children age 3-5

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53
Q

What is erysipelas?

A

-an infection of the dermis caused by S. pyogenes

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54
Q

What is the symptom of erysipelas?

A

-skin errupts into reddish patches with raised margins

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55
Q

What antibiotic usually is sensitive to S. pyogenes?

A

cephalosporins and penicillin

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56
Q

What can erysipelas become if not treated?

A

septicemia

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57
Q

What is necrotizing fasciitis?

A

-a GAS infection that eats away the fascia of connective tissue
-aka flesh eating disease

58
Q

What is the mortality rate of necrotizing fasciitis?

A

~50%

59
Q

How does necrotizing fasciitis enter?

A

through breaks in the skin, exoenzymes

60
Q

What does NF secrete?

A

collagenase, hyaluronidase, and Exotoxin A

61
Q

Is Pseudomonas aeruginosa gram negative or positive?

A

negative

62
Q

Does P. aeruginosa dermatitis require hospitalization?

A

usually no, takes care of itself

63
Q

What may cause dermatitis?

A

water (pools, hot tub)

64
Q

How long does dermatitis usually last?

A

2 weeks

65
Q

What is otitis externa and what bacteria causes it?

A

infection of the outer ear caused by P. aeruginosa

66
Q

What causes otitis externa?

A

natural bodies of water

67
Q

When is otitis externa bad?

A

if it infects the ear drum

68
Q

How can P. aeruginosa lead to nosocomial infections?

A

can enter hospitals through flower vases, mop water

69
Q

What do P. aeruginosa infections cause in post burn victims?

A

blue/green pus and a prolonged hospital stay

70
Q

P. aeruginosa can lead to infection is immunosuppressed patients like…

A

cancer patients and CF patients

71
Q

P. aeruginosa releases ______ and ______ toxins.

A

endo and exo

72
Q

What pigment causes the blue/green pus?

A

pyocyanin

73
Q

What virus causes warts?

A

Human Papillomavirus (HPV)

74
Q

How many HPV species are there and how many are associated with cancers?

A

50 species, 16 and 18 associated with cancer

75
Q

How do warts spread?

A

-contact
-fomites
-sexual contact
-moist areas

76
Q

How are warts treated?

A

-liquid nitrogen
-electrodessication/ cauterization
-laser surgery
-24% salicylic acid

77
Q

What is the most common STI?

A

genital warts

78
Q

HHV-3

A

-varicellovirus
-chicken pox and shingles

79
Q

How is chicken pox transmitted?

A

respiratory route

80
Q

Chicken Pox Symptoms

A

-infection localizes in the skin cells after 2 weeks
-vesicular skin infection for 3-4 days

81
Q

When can chicken pox be dangerous?

A

during preganacy

82
Q

Where does chicken pox remain latent?

A

in the dorsal root ganglia

83
Q

Is there a chicken pox vaccine available?

A

yes

84
Q

Whats another name for chicken pox?

A

varicella

85
Q

How do chicken pox wounds appear?

A

first as dots on skin (macule), then papule, then a fluid filled vesicle, then pustule (itchy pus filled), crust, scar

86
Q

Exantham

A

a skin rash arising from another focus of infection (ie. chicken pox moves from respiratory tract to blood to skin)

87
Q

What does chicken pox reappear as?

A

shingles (zoster)

88
Q

Where does shingles affect?

A

-the girdle area (abdominal belt)

89
Q

What is used to treat shingles?

A

acyclovir

90
Q

What characterizes shingles?

A

-not itchy
-painful
-longer lasting (up to weeks)

91
Q

Shingles is an __________.

A

exanthema

92
Q

Is there a vaccine for shingles?

A

yes; for people ages 50+ called shingrix

93
Q

What can trigger HHV-3 to reactivate?

A

stress, aging

94
Q

What does HHV stand for?

A

Human herpesvirus

95
Q

What does HSV stand for?

A

Herpes simplex virus

96
Q

How is HSV-1 transmitted?

A

oral or respiratory routes

97
Q

What is a symptom of HSV-1?

A

lesions called cold sores or fever blisters

98
Q

Where does HSV-1 lay latent?

A

in the trigeminal nerve ganglia that communicates between the face and CNS

99
Q

What can trigger recurrences of HSV-1?

A

UV radiation from the sun, emotional upsets, menstrual hormone changes

100
Q

Does HSV need signs and symptoms to spread?

A

no

101
Q

How is HSV-2 spread?

A

sexual or oral contact

102
Q

How do HSV 1 and 2 differ?

A

-antigenic makeup and affect on cells in cell culture
-location where they lie latent

103
Q

Where does HSV-2 lay latent?

A

in the sacral nerve ganglia near the base of the spine

104
Q

Is HSV-1 or 2 more virulent?

A

2

105
Q

Herpes Encephalitis

A

-when HSV-1 or 2 can rarely spread to the brain
-HSV-2 is more serious and has a 70% mortality rate

106
Q

How is HSV-2 encephalitis treated?

A

acyclovir

107
Q

Transfer between HSV-1 and HSV-2 can only happen during ____ _____.

A

oral sex

108
Q

Herpetic Whitlow

A

-infection of the finger
-common in healthcare professionals

109
Q

Measles and Rubella are ________.

A

exanthams

110
Q

How is measles spread?

A

respiratory route

111
Q

Why is quarantine not an option for preventing measles?

A

a person with measles is infectious before symptoms appear

112
Q

Are there any antivirals that treat measles?

A

no

113
Q

Is there a vaccine fore measles?

A

Yes, the MMR vaccine that has 90% efficacy

114
Q

Who is most at risk for measles?

A

-infants, children, pregnancy

115
Q

What are the initial symptoms of measles?

A

cold-like symptoms

116
Q

Koplik’s Spots

A

-measles macular rash in the oral cavity
-look like salt on red bumps

117
Q

The presence of Koplik’s spots is the ________ indicator for measles.

A

diagnostic

118
Q

Measles and Encephalitis

A

-1/1000 measles victims
-brain degeneration

119
Q

Subacute Sclerosing Panencephalitis

A

-1 in a million cases
-1 to 10 years after measles recovery
-severe neurological symptoms and eventually death

120
Q

What complicates measles?

A

otitis media and pneumonia

121
Q

Rubella is ________ than measles

A

milder

122
Q

Are there any antivirals to treat Rubella?

A

no

123
Q

Is there a vaccine for Rubella?

A

yes; MMR

124
Q

What is another name for measles?

A

rubeola

125
Q

What are the usual symptoms of Rubella?

A

-mild pink rash
-light fever
-no Koplik’s spots

126
Q

How is Rubella transmitted?

A

respiratory route

127
Q

What is the incubation period of Rubella?

A

2 to 3 weeks

128
Q

Congenital Rubella Syndrome

A

-35% incidence of serious fetal damage if mother contracts during first 3 months
-leads to deafness, cataracts, heart and mental defects, maybe death

129
Q

Does the Rubella rash have raised spots?

A

no

130
Q

Conjuctivitis

A

inflammation of the conductive aka pinkeye

131
Q

Conjunctivitis can be caused by _______ or _______.

A

bacteria (ie. H. influenzae) or virus (ie. measles)

132
Q

Symptoms of Conjunctivitis

A

-pus (usually bacterial)
-redness
-red
-watery
-swollen

133
Q

Whats a common cause of Pseudomonas Conjunctivitis?

A

-unsanitary contact lenses

134
Q

How is Conjunctivitis treated?

A

antibiotics

135
Q

What pathogen causes trachoma?

A

Chlamydia trachomatis

136
Q

What is the leading cause of blindness?

A

Trachoma

137
Q

Trachoma symptoms

A

-Conjunctivitis of eyelids, eyelids turn inward and abrade corneas (=blindness)

138
Q

Trichiasis

A

-occurs when in-turned eyelid abrades cornea
-leads to blindness

139
Q

How to fix in-turned eyelid?

A

surgery

140
Q

How is trachoma treated?

A

tetracycline or erythromycin, penicillin

141
Q

How is trachoma spread?

A

-unsanitary conditions
-overpopulation
-unavailable medical resources