Unit 5 - Chapter 21 - Information

Question 1

epidermidis

Answer 1

thin outer portion composed of several layers of epithelial cells, an effective physical barrier against microorganisms

Question 2

stratum corneum

which layer
contains what?

Answer 2

outermost layer of the epidermis, consists of many rows of dead cells that contain waterproofing protein called keratin

Question 3

keratin

Answer 3

waterproofing protein in stratum corneum

Question 4

dermis

composed of what?
what is in it?

Answer 4

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

Question 5

perspiration

salt
lysozyme
3rd thing

Answer 5

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

Question 6

sebum

secreted by what, and what does it contain?

Answer 6

secreted by oil glands, mixture of lipids, proteins, and salts that prevents skin and hair from drying out. Nutritive for many microorganisms.

Question 7

lysozyme

Answer 7

enzyme that digests peptidoglycans

Question 8

salt

Answer 8

in perspiration & sebum, inhibits many microorganisms

Question 9

fatty acids

Answer 9

in perspiration & sebum, inhibits microbes

Question 10

antimicrobial peptides

Answer 10

defensins of the skin

Question 11

gram positive normal flora

numbers and 2 types

Answer 11

large numbers, include staphylococci and micrococci

Question 12

staphylococci

gram status
part of…
resistance to…

Answer 12

gram positive, part of the skin’s normal microbiota; relatively resistant to environmental stresses such as drying and high-salt

Question 13

propionibacterium acnes

shape
aerobic status
where does it inhabit
growth supported by what?
causes what?

Answer 13

diptheroids (pleomorphic rods), typically anaerobic, inhabit hair follicles. Growth is supported by sebum, cause acne

Question 14

gram negative normal flora

2 types

Answer 14

Acinetobacter, Malassezia furfur (yeast that causes dandruff)

Question 15

vesicles

Answer 15

small, fluid-filled lesions

Question 16

bullae

Answer 16

vesicles larger than about 1cm

Question 17

macules

Answer 17

flat, reddened lesions

Question 18

papules

Answer 18

raised lesions

Question 19

pustules

Answer 19

lesions containing pus

Question 20

exanthem

Answer 20

skin rash that arises from disease conditions

Question 21

enanthem

Answer 21

skin rash that occurs on mucous membranes (such as interior of the mouth)

Question 22

Staphylococci

shape
gram status
arrangement
spore status
motility status

Answer 22

spherical, G+, irregular clusters, non-spore forming, nonmotile

Question 23

Staphylococcus epidermidis

coagulase status
what percentage of what?
pathogenicity

Answer 23

coagulase –; 90% of the normal microbiota; not pathogenic unless skin is broken

Question 24

Staphylococcus aureus -

coagulase status
mannitol salt agar culture friendly?
catalase status
pathogenicity
location & population percentage

Answer 24

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

Question 25

S. aureus - virulence and host evasion

Answer 25

have a lot of virulence factors and means of evading host defenses

Question 26

S. aureus - when it infects (inflammation)

Answer 26

when it infects, it stimulates a vigorous inflammatory response and macrophages & neutrophils are attracted to the infection site

Question 27

S. aureus - how it evades host defenses ``` blocks c... produces t... resistant to o... produces p... resistant to l... ```

Answer 27

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

Question 28

enzymes S. aureus produces: H S D L

Answer 28

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

Question 29

Bacillus anthracis

Answer 29

cutaneous anthrax - most common and least dangerous; caused by endospores entering through skin through small cuts/abrasions

Question 30

Streptococcus pyogenes which group is most important pathogencity commonality reponsible for... cells contain...

Answer 30

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.

Question 31

S. pyogenes: M protein prevents: allows microbe to:

Answer 31

prevents the activation of complement allows the microbe to evade phagocytosis and killing by neutrophils

Question 32

Strep pyogenes enzymes: S S H D

Answer 32

Streptokinases: dissolve blood clots Streptolysin: lyse RBC Hyaluronidase: dissolve hyaluronic acid in connective tissues DNAse: degrades dna (deoxyribonucleases)

Question 33

pseudomonads ``` aerobic status gram status where is it located? capable of surviving... resistant to... causes what disease? ```

Answer 33

aerobic, G -, in soil & water. Capable of surviving in any most environment, resistant to many antibiotics and disinfectants. Cause pseudomonas dermatitis.

Question 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?

Answer 34

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.

Question 35

hhv-3

Answer 35

enveloped DNA virus;

Question 36

hhv-3 diseases caused

Answer 36

causes chickenpox and herpes zoster (shingles);

Question 37

hhv-3 incubation pd

Answer 37

incubation period is 10-20 days;

Question 38

hhv-3 first symptoms

Answer 38

fever, rash

Question 39

hhv-3 portal of entry Enters where Attaches to what Invades & enters what?

Answer 39

enters respiratory tract, attaches to respiratory mucosa, then invades and enters bloodstream.

Question 40

hhv-3 latency

Answer 40

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.

Question 41

hhv-3 mode of transmission

Answer 41

respiratory droplets

Question 42

hhv-3 contagiousness

Answer 42

very contagious--almost certainly will get it once exposed to it

Question 43

hhv-3 vaccine

Answer 43

live attenuated vaccine; zostavax is for 60+

Question 44

hhv-3 treatment

Answer 44

acyclovir

Question 45

mycosis

Answer 45

fungal infection

Question 46

dermatophytes

Answer 46

fungi that colonize the hair, nails, and outer layer (stratum corneum) of the epidermis; grow on keratin

Question 47

tineas

Answer 47

ringworm, dermatomycoses (skin disease caused by fungus); caused fungal infections

Question 48

tinea pedis

Answer 48

athletes foot, ringworm of the feet

Question 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? ```

Answer 49

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

Question 50

streptococcal toxic shock syndrome ``` resembles... symptoms caused by what protein, which forms what complex, which binds to what? Causes what to the body? Mortality rate % ```

Answer 50

resembles staphylococcal TSS; rash is less likely to be present, but bacteremia is more likely to occur. M proteins shed from the surfaces of these streptococci form a complex with fibrinogen that binds to neutrophils. This causes activation of the neutrophils, precipitating the releasing of damaging enzymes and consequently shock and organ damage. Mortality rate is much higher than with staph TSS (80%)