Unit 5 - Chapter 21 - Information Flashcards Preview

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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

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 %

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%)