Microbiology - Dermatology

Question 1

what is virulence?

Answer 1

the ability of an organism to cause disease within a host

Question 2

name five virulence factors

Answer 2

adhesin 
impedin 
invasin 
aggressin 
modulin

Question 3

what are adhesins?

Answer 3

bacterial cell surface components that help the organism stick to host tissues

Question 4

what are invasins?

Answer 4

components that enable organisms to invade host tissue

Question 5

what are impedins?

Answer 5

components that help the organism avoid the immune response in host tissue

Question 6

what are aggressins?

Answer 6

components that cause direct damage to host tissue and immune cells, affecting the hosts ability to cope with disease in the future

Question 7

what are modulins?

Answer 7

components that cause indirect damage to the host by turning the immune system on itself

Question 8

true or false: the nasal strain of staph aureus can protect the mucosa

Answer 8

true

Question 9

true or false: staph epidermidis can occupy up to 100% of our skin

Answer 9

true

Question 10

where is the most common entry or staph aureus into the body?

Answer 10

the nose

Question 11

name the three main important virulence factors of staph aureus infection

Answer 11

fibrinogen binding protein
leukocidin
TSST 1

Question 12

what type of virulence factor is fibrinogen binding protein?

Answer 12

adhesin

Question 13

what does leukocidin do?

Answer 13

kills leukocytes

Question 14

true or false: every strain of staph aureus carries every virulence factor

Answer 14

false

Question 15

which two severe skin diseases is leukocidin associated with?

Answer 15

necrotising fasciitis

recurrent furunculosis

Question 16

true or false: leukocidin is more virulent in hospital acquired MRSA than community acquired

Answer 16

false

Question 17

name a superantigen released by MRSA

Answer 17

TSST 1

Question 18

what does TSST 1 cause?

Answer 18

toxic shock syndrome

Question 19

how do superantigens avoid specific T cell activation?

Answer 19

bind to MHC II complex on the outside (not how they conventionally bind)

Question 20

name three skin infections caused by strep pyogenes

Answer 20

impetigo
cellulitis
necrotising fasciitis

Question 21

how does the lancefield system classify different subtypes of strep pyogenes?

Answer 21

M protein

Question 22

which two virulence factors are particularly important as adhesins for strep pyogenes?

Answer 22

hyaluronic acid

CD44 positive keratinocytes

Question 23

true or false: the bigger the capsule the less virulent an organism is

Answer 23

false

Question 24

where does impetigo usually affect?

Answer 24

the face

Question 25

where in the body is strep pyogenes normally found?

Answer 25

the throat

Question 26

which strain of staph aureus commonly produces abscesses and boils, usually affecting numerous family members at once/

Answer 26

PVL (panton valentine leukocidin)

Question 27

which group of strep causes throat and severe skin infections?

Answer 27

group A

Question 28

which bacteria causes impetigo?

Answer 28

staph aureus | group A strep

Question 29

which bacteria tends to cause necrotising fasciitis?

Answer 29

group A strep (strep pyogenes)

Question 30

what is the treatment of choice for staph aureus?

Answer 30

flucloxacillin

Question 31

what is the treatment of choice for strep pyogenes?

Answer 31

penicillin

Question 32

what is necrotising fasciitis?

Answer 32

bacterial infection spreading under the skin into the fascia

Question 33

what is the nickname for necrotising fasciitis?

Answer 33

flesh eating bacterial disease

Question 34

true or false: type I necrotising fasciitis is caused by group A strep

Answer 34

false type I = mixed anaerobes and coliforms II = group A strep

Question 35

what is the most common skin fungal infection caused by?

Answer 35

ringworm

Question 36

what is another name for athlete's foot?

Answer 36

tinea pedis

Question 37

how is dermatophyte infection caused?

Answer 37

fungus enters abraded skin and infects keratinised tissue, provoking inflammation and outward lesioning

Question 38

which organism is the most common cause of dermatophyte infection?

Answer 38

trichophyton rubrum

Question 39

how are small areas of dermatophyte infection treated?

Answer 39

clotrimazole cream | nail paint

Question 40

how are dermatophyte scalp infections treated?

Answer 40

terbinafine oral | itraconzole oral

Question 41

which parasite causes scabies?

Answer 41

sarcoptes scabiei

Question 42

how long does incubation of scabies take?

Answer 42

up to six weeks

Question 43

how is scabies treated?

Answer 43

malathion lotion overnight | benzyl benzoate in adults

Question 44

what virus cause chickenpox and shingles?

Answer 44

varicella zoster

Question 45

where does varicella zoster become dormant following chickenpox?

Answer 45

dorsal root ganglia of the spine

Question 46

true or false: chickenpox can cause pneumonitis and encephalitis

Answer 46

true

Question 47

what is ramsay hunt syndrome?

Answer 47

reactivation of varicella zoster in CN VII causes vesicles and pain in the auditory canal and throat

Question 48

what does herpes simplex virus cause around the mouth?

Answer 48

primary gingivostomatitis | extensive ulceration

Question 49

what is the treatment of choice for varicella zoster and herpes simplex virus?

Answer 49

aciclovir

Question 50

which virus tends to cause warts?

Answer 50

human papilloma virus

Question 51

which treatment is effective for warts?

Answer 51

salicylic acid

Question 52

which bacterium causes syphilis?

Answer 52

treponema pallidum

Question 53

how is syphilis tretaed?

Answer 53

penicillin injections