Chapter 21 - Microbial Diseases of the Skin and Eyes Flashcards
1
Q
Staphylococcus Aureus affects the _____.
A
skin
2
Q
Staphylococcus aureus is gram +/-?
A
positive
3
Q
S.aureus is coagulase ________ meaning….
A
-positive
-it can produce coagulase
4
Q
Coagulase
A
-an enzyme that clots fibrin in blood
5
Q
Staphylococcus epidermis is coagulase _________ meaning….
A
-negative
-it does not produce coagulase
6
Q
S. epidermidis make up ___% of normal microbiota on the skin
A
90
7
Q
When is S. epidermidis pathogenic?
A
when the skin barrier is broken or invaded by medical procedures (ie. catheter)
8
Q
Which staphylococci is the most pathogenic?
A
S. aureus
9
Q
What is the purpose of the gold pigment in S. aureus?
A
-protects against the antimicrobial effects of sunlight
10
Q
Enterotoxins
A
-affect GI tract
11
Q
How does S. aureus invade?
A
-direct invasion, attach to follicle
-stimulates vigorous inflammatory response
-produces toxins that kill phagocytic cells
12
Q
Where is S. aureus common in humans?
A
nasal passages
13
Q
Folliculitis
A
-a symptom of S. aureus
-often occur as pimples
14
Q
Sty
A
-a symptom of S. aureus
-the infected follicle of an eyelash
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
16
Q
Carbuncle
A
-development of furuncle of S. aureus
-inflammation of tissue under the skin
-usually has fever
17
Q
What is the treatment of a carbuncle?
A
-surgery
-penicillin
18
Q
What bacteria causes impetigo?
A
Staphylococci
19
Q
What is impetigo?
A
-highly contagious skin infection
-affects children age 2-5
-yellow crusts
20
Q
Pemphigus Neonatorum
A
impetigo of the newborn
21
Q
Does impetigo use an exotoxin?
A
no
22
Q
Impetigo is a __________ meaning…
A
pyoderma; pus in the skin
23
Q
Scalded Skin Syndrome (SSSS)
A
-redness
-itching
-blisters
-exfoliation, separation of skin layers
-contagious clear fluid filled blisters
24
Q
What is a big risk of SSSS?
A
secondary infection, SSSS is a great portal of entry for other bacteria
25
Who is most at risk of SSSS?
in children and elderly
26
How do you treat SSSS?
-penicillin
-isolation
-clean fomites
27
What is the role of the exotoxin in SSSS?
-it is exfoliative
-breaks ester bonds between skin cells
28
Desquamation
skin shedding
29
Exfoliative Toxin A
-local
-causes bullous impetigo
30
Exfoliative Toxin B
-circulates
-causes SSSS
31
What does SSSS stand for?
Staphylococcal Scalded Skin Syndrome
32
Name 3 ways someone can get TSS
1. tampon use
2. surgical wound
3. childbirth
33
Why are tampons such a good medium for bacterial growth?
-blood makes them nutrient rich
-abrasive material
34
Symptoms of TSS
-fever
-aches
-nausea
-vomiting
-confusion
-shock (impaired kidney function)
-red skin rash
35
What can the TSS rash be?
SSSS
36
What is the occurrence of death with with TSS?
less than 3%
37
TSS Toxin 1 and 2
-formed at the growth site and circulates in the bloodstream
38
Why do TSS symptoms result?
Super antigenic properties of the toxin
39
How to prevent TSS?
-hand washing
-frequently changing tampons
-using pads or menstrual cups
40
Streptococci are gram ____ bacteria
positive
41
What do streptococci secrete as they grow?
toxins and enzymes
42
__________ are a toxin released by streptococci?
hemolysins; they lyse red blood cells
43
What two categories are streptococci grouped into?
alpha-hemolytic and beta-hemolytic
44
What is GAS?
group A streptococci
45
How are streptococci grouped by serology?
according to antigenic carbohydrates in their cell walls
46
GAS are synonymous with Streptococcus ________.
pyogenes
47
What kind of hemolytic group is S. pyogenes?
beta-hemolytic
48
Streptolysins
-released by S. pyogenes
-lyse red blood cells
-toxic to neutrophils
49
S. pyogenes has ________ which is...
M protein; external to the cell walls prevents the activation and allows the microbe to evade phagocytosis and neutrophils and colonize mucous membranes
50
Does GAS have a capsule?
yes
51
What does GAS produce?
-streptokinases (dissolve blood clots)
-hyaluronidase (cements cells together)
-deoxyribonucleases (degrade DNA)
52
What is a common infection S. aureus and S. pyogenes cause?
Impetigo in children age 3-5
53
What is erysipelas?
-an infection of the dermis caused by S. pyogenes
54
What is the symptom of erysipelas?
-skin errupts into reddish patches with raised margins
55
What antibiotic usually is sensitive to S. pyogenes?
cephalosporins and penicillin
56
What can erysipelas become if not treated?
septicemia
57
What is necrotizing fasciitis?
-a GAS infection that eats away the fascia of connective tissue
-aka flesh eating disease
58
What is the mortality rate of necrotizing fasciitis?
~50%
59
How does necrotizing fasciitis enter?
through breaks in the skin, exoenzymes
60
What does NF secrete?
collagenase, hyaluronidase, and Exotoxin A
61
Is Pseudomonas aeruginosa gram negative or positive?
negative
62
Does P. aeruginosa dermatitis require hospitalization?
usually no, takes care of itself
63
What may cause dermatitis?
water (pools, hot tub)
64
How long does dermatitis usually last?
2 weeks
65
What is otitis externa and what bacteria causes it?
infection of the outer ear caused by P. aeruginosa
66
What causes otitis externa?
natural bodies of water
67
When is otitis externa bad?
if it infects the ear drum
68
How can P. aeruginosa lead to nosocomial infections?
can enter hospitals through flower vases, mop water
69
What do P. aeruginosa infections cause in post burn victims?
blue/green pus and a prolonged hospital stay
70
P. aeruginosa can lead to infection is immunosuppressed patients like...
cancer patients and CF patients
71
P. aeruginosa releases ______ and ______ toxins.
endo and exo
72
What pigment causes the blue/green pus?
pyocyanin
73
What virus causes warts?
Human Papillomavirus (HPV)
74
How many HPV species are there and how many are associated with cancers?
50 species, 16 and 18 associated with cancer
75
How do warts spread?
-contact
-fomites
-sexual contact
-moist areas
76
How are warts treated?
-liquid nitrogen
-electrodessication/ cauterization
-laser surgery
-24% salicylic acid
77
What is the most common STI?
genital warts
78
HHV-3
-varicellovirus
-chicken pox and shingles
79
How is chicken pox transmitted?
respiratory route
80
Chicken Pox Symptoms
-infection localizes in the skin cells after 2 weeks
-vesicular skin infection for 3-4 days
81
When can chicken pox be dangerous?
during preganacy
82
Where does chicken pox remain latent?
in the dorsal root ganglia
83
Is there a chicken pox vaccine available?
yes
84
Whats another name for chicken pox?
varicella
85
How do chicken pox wounds appear?
first as dots on skin (macule), then papule, then a fluid filled vesicle, then pustule (itchy pus filled), crust, scar
86
Exantham
a skin rash arising from another focus of infection (ie. chicken pox moves from respiratory tract to blood to skin)
87
What does chicken pox reappear as?
shingles (zoster)
88
Where does shingles affect?
-the girdle area (abdominal belt)
89
What is used to treat shingles?
acyclovir
90
What characterizes shingles?
-not itchy
-painful
-longer lasting (up to weeks)
91
Shingles is an __________.
exanthema
92
Is there a vaccine for shingles?
yes; for people ages 50+ called shingrix
93
What can trigger HHV-3 to reactivate?
stress, aging
94
What does HHV stand for?
Human herpesvirus
95
What does HSV stand for?
Herpes simplex virus
96
How is HSV-1 transmitted?
oral or respiratory routes
97
What is a symptom of HSV-1?
lesions called cold sores or fever blisters
98
Where does HSV-1 lay latent?
in the trigeminal nerve ganglia that communicates between the face and CNS
99
What can trigger recurrences of HSV-1?
UV radiation from the sun, emotional upsets, menstrual hormone changes
100
Does HSV need signs and symptoms to spread?
no
101
How is HSV-2 spread?
sexual or oral contact
102
How do HSV 1 and 2 differ?
-antigenic makeup and affect on cells in cell culture
-location where they lie latent
103
Where does HSV-2 lay latent?
in the sacral nerve ganglia near the base of the spine
104
Is HSV-1 or 2 more virulent?
2
105
Herpes Encephalitis
-when HSV-1 or 2 can rarely spread to the brain
-HSV-2 is more serious and has a 70% mortality rate
106
How is HSV-2 encephalitis treated?
acyclovir
107
Transfer between HSV-1 and HSV-2 can only happen during ____ _____.
oral sex
108
Herpetic Whitlow
-infection of the finger
-common in healthcare professionals
109
Measles and Rubella are ________.
exanthams
110
How is measles spread?
respiratory route
111
Why is quarantine not an option for preventing measles?
a person with measles is infectious before symptoms appear
112
Are there any antivirals that treat measles?
no
113
Is there a vaccine fore measles?
Yes, the MMR vaccine that has 90% efficacy
114
Who is most at risk for measles?
-infants, children, pregnancy
115
What are the initial symptoms of measles?
cold-like symptoms
116
Koplik's Spots
-measles macular rash in the oral cavity
-look like salt on red bumps
117
The presence of Koplik's spots is the ________ indicator for measles.
diagnostic
118
Measles and Encephalitis
-1/1000 measles victims
-brain degeneration
119
Subacute Sclerosing Panencephalitis
-1 in a million cases
-1 to 10 years after measles recovery
-severe neurological symptoms and eventually death
120
What complicates measles?
otitis media and pneumonia
121
Rubella is ________ than measles
milder
122
Are there any antivirals to treat Rubella?
no
123
Is there a vaccine for Rubella?
yes; MMR
124
What is another name for measles?
rubeola
125
What are the usual symptoms of Rubella?
-mild pink rash
-light fever
-no Koplik's spots
126
How is Rubella transmitted?
respiratory route
127
What is the incubation period of Rubella?
2 to 3 weeks
128
Congenital Rubella Syndrome
-35% incidence of serious fetal damage if mother contracts during first 3 months
-leads to deafness, cataracts, heart and mental defects, maybe death
129
Does the Rubella rash have raised spots?
no
130
Conjuctivitis
inflammation of the conductive aka pinkeye
131
Conjunctivitis can be caused by _______ or _______.
bacteria (ie. H. influenzae) or virus (ie. measles)
132
Symptoms of Conjunctivitis
-pus (usually bacterial)
-redness
-red
-watery
-swollen
133
Whats a common cause of Pseudomonas Conjunctivitis?
-unsanitary contact lenses
134
How is Conjunctivitis treated?
antibiotics
135
What pathogen causes trachoma?
Chlamydia trachomatis
136
What is the leading cause of blindness?
Trachoma
137
Trachoma symptoms
-Conjunctivitis of eyelids, eyelids turn inward and abrade corneas (=blindness)
138
Trichiasis
-occurs when in-turned eyelid abrades cornea
-leads to blindness
139
How to fix in-turned eyelid?
surgery
140
How is trachoma treated?
tetracycline or erythromycin, penicillin
141
How is trachoma spread?
-unsanitary conditions
-overpopulation
-unavailable medical resources
