Flashcards in Unit 5 - Chapter 21 - Information Deck (50)
1
epidermidis
thin outer portion composed of several layers of epithelial cells, an effective physical barrier against microorganisms
2
stratum corneum
which layer
contains what?
outermost layer of the epidermis, consists of many rows of dead cells that contain waterproofing protein called keratin
3
keratin
waterproofing protein in stratum corneum
4
dermis
composed of what?
what is in it?
inner, relatively thick portion of skin, composed mainly of connective tissue.
Hair follicles, sweat glands, oil glands in dermis provide passageways through which microorganisms can enter skin and penetrate deeper tissues
5
perspiration
salt
lysozyme
3rd thing
provides moisture and some nutrients for microbial growth.
Contains SALT which inhibits many microorganisms
and LYSOZYME, capable of breaking down cell wall of bacteria,
and ANTIMICROBIAL PEPTIDES
6
sebum
secreted by what, and what does it contain?
secreted by oil glands, mixture of lipids, proteins, and salts that prevents skin and hair from drying out. Nutritive for many microorganisms.
7
lysozyme
enzyme that digests peptidoglycans
8
salt
in perspiration & sebum, inhibits many microorganisms
9
fatty acids
in perspiration & sebum, inhibits microbes
10
antimicrobial peptides
defensins of the skin
11
gram positive normal flora
numbers and 2 types
large numbers, include staphylococci and micrococci
12
staphylococci
gram status
part of...
resistance to...
gram positive, part of the skin's normal microbiota; relatively resistant to environmental stresses such as drying and high-salt
13
propionibacterium acnes
shape
aerobic status
where does it inhabit
growth supported by what?
causes what?
diptheroids (pleomorphic rods), typically anaerobic, inhabit hair follicles. Growth is supported by sebum, cause acne
14
gram negative normal flora
2 types
Acinetobacter, Malassezia furfur (yeast that causes dandruff)
15
vesicles
small, fluid-filled lesions
16
bullae
vesicles larger than about 1cm
17
macules
flat, reddened lesions
18
papules
raised lesions
19
pustules
lesions containing pus
20
exanthem
skin rash that arises from disease conditions
21
enanthem
skin rash that occurs on mucous membranes (such as interior of the mouth)
22
Staphylococci
shape
gram status
arrangement
spore status
motility status
spherical, G+, irregular clusters, non-spore forming, nonmotile
23
Staphylococcus epidermidis
coagulase status
what percentage of what?
pathogenicity
coagulase --; 90% of the normal microbiota; not pathogenic unless skin is broken
24
Staphylococcus aureus -
coagulase status
mannitol salt agar culture friendly?
catalase status
pathogenicity
location & population percentage
coagulase +
mannitol salt agar +
catalase +
the most pathogenic staphylococci
permanent resident of nasal passages of 20% of the population; an additional 60% carry it there occasionally
25
S. aureus - virulence and host evasion
have a lot of virulence factors and means of evading host defenses
26
S. aureus - when it infects (inflammation)
when it infects, it stimulates a vigorous inflammatory response and macrophages & neutrophils are attracted to the infection site
27
S. aureus - how it evades host defenses
blocks c...
produces t...
resistant to o...
produces p...
resistant to l...
blocks chemotaxis of neutrophils to site;
produces toxins that kill macrophages;
resistant to opsonization;
produces proteins to neutralize antimicrobial peptide defensins of skin;
cell wall is resistant to lysozyme
28
enzymes S. aureus produces:
H
S
D
L
hyaluronidase: digests the intercellular hyaluronic acid that binds connective tissue
staphylokinase: digests blood clots
DNAse: degrades DNA - deoxyribonuclease
lipase: helps bacteria colonize on oily skin surfaces
29
Bacillus anthracis
cutaneous anthrax - most common and least dangerous; caused by endospores entering through skin through small cuts/abrasions
30
Streptococcus pyogenes
which group is most important
pathogencity commonality
reponsible for...
cells contain...
Group A strep is most important beta-hemolytic streptococci
most common human pathogen,
responsible for a number of human diseases;
cells contain hemolysins that can lyse RBCs and almost any type of cell.
31
S. pyogenes: M protein
prevents:
allows microbe to:
prevents the activation of complement
allows the microbe to evade phagocytosis and killing by neutrophils
32
Strep pyogenes enzymes:
S
S
H
D
Streptokinases: dissolve blood clots
Streptolysin: lyse RBC
Hyaluronidase: dissolve hyaluronic acid in connective tissues
DNAse: degrades dna (deoxyribonucleases)
33
pseudomonads
aerobic status
gram status
where is it located?
capable of surviving...
resistant to...
causes what disease?
aerobic,
G -,
in soil & water.
Capable of surviving in any most environment,
resistant to many antibiotics and disinfectants.
Cause pseudomonas dermatitis.
34
P. aeruginosa toxins
produces how many exotoxins and endotoxins?
grows in what, which contributes to what?
what kind of pathogen for what kind of patients?
produces several exotoxins and 1 endotoxin,
grows in dense biofilms that contribute to its frequent identification as a cause of nosocomial infections of indwelling medical tubes/devices.
A serious opportunistic pathogen for patients w/ cystic fibrosis & burn patients w/ 2nd/3rd degree burns.
35
hhv-3
enveloped DNA virus;
36
hhv-3 diseases caused
causes chickenpox and herpes zoster (shingles);
37
hhv-3 incubation pd
incubation period is 10-20 days;
38
hhv-3 first symptoms
fever, rash
39
hhv-3 portal of entry
Enters where
Attaches to what
Invades & enters what?
enters respiratory tract, attaches to respiratory mucosa, then invades and enters bloodstream.
40
hhv-3 latency
virus enters sensory nerves and travels to dorsal root ganglia, where it remains latent. Provides a resevoir of virus for the reactivation condition of shingles.
41
hhv-3 mode of transmission
respiratory droplets
42
hhv-3 contagiousness
very contagious--almost certainly will get it once exposed to it
43
hhv-3 vaccine
live attenuated vaccine; zostavax is for 60+
44
hhv-3 treatment
acyclovir
45
mycosis
fungal infection
46
dermatophytes
fungi that colonize the hair, nails, and outer layer (stratum corneum) of the epidermis; grow on keratin
47
tineas
ringworm, dermatomycoses (skin disease caused by fungus); caused fungal infections
48
tinea pedis
athletes foot, ringworm of the feet
49
scalded skin syndrome -
caused by which toxin?
endo or exotoxin
encoded by phage or plasmid?
toxin causes what?
toxin enters where and goes where?
caused by staphylococcal toxin, caused by exfoliative toxins A and B (exotoxins),
encoded by a phage.
The toxins cause a separation in the skin layers.
Toxins enter through blood stream to some focus of infection (throat, eye, impetigo infection) and travel throughout body). Split occurs just above stratum basale
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