Microbiology

Question 1

how does the skin protect itself from invasion?

Answer 1

produces sebum (inhibits bacterial growth)
dry skin
competitive bacterial flora

Question 2

examples of competitive bacteria flora on the skin

Answer 2

staph epidermidis
corynebacterium
propionibacterium

Question 3

virulence factors

Answer 3

adhesin
invasin
impedin
aggressin
modulin

Question 4

define adhesin

Answer 4

enables binding of the organism to host tissue

Question 5

define invasin

Answer 5

enables organism to invade host cell/tissue

Question 6

define impedin

Answer 6

enables organism to avoid host defence mechanisms

Question 7

define aggressin

Answer 7

causes damage to the host directly

Question 8

define modulin

Answer 8

induces damage to the host indirectly

Question 9

can staph aureus be carried on the skin?

Answer 9

yes

Question 10

virulence factors of staph aureus

Answer 10

fibrinogen binding protein
leucocidin
enterotoxin
TSST-1 (super-antigen)
coagulase positive
PVL strain

Question 11

define leucocidin of staph aureus

Answer 11

exotoxin causing leucocyte killing

Question 12

define enterotoxin of staph aureus

Answer 12

food poisoning

Question 13

define TSST-1

Answer 13

this is a superantigen that causes vomiting, fever, scalded skin syndrome and toxic shock syndrome due to a massive release of cytokines

Question 14

what does coagulase positive mean?

Answer 14

plasma clotting

Question 15

what is the toxin PVL produced by a strain of staph aureus?

Answer 15

Panton-Valentine-Leukocidin

Question 16

what does the PVL toxin do?

Answer 16

leucocyte killer

Question 17

what conditions does the PVL toxin cause?

Answer 17

furunculosis
necrotising pneumonia
necrotising fasciitis

Question 18

management of staph aureus infection

Answer 18

flucloxacillin

Question 19

when is flucloxacillin not used in treatment of staph aureus?

Answer 19

MRSA

Question 20

management for MRSA

Answer 20

doxycycline, co-trimoxazole, clindamycin and linezolid for skin and vancomycin for bacteria

Question 21

what category is strep pyogenes in?

Answer 21

group A strep (beta haemolysis)

Question 22

skin infections caused by strep pyogenes

Answer 22

impetigo
cellulitis
necrotising fasciitis

Question 23

presentation of impetigo

Answer 23

honey coloured crust

Question 24

causes of impetigo

Answer 24

strep pyogenes

staph aureus

Question 25

what is cellulitis

Answer 25

deeper infection of the dermis not associated with necrosis

Question 26

what is necrotising fasciitis

Answer 26

destroys connective tissue with streptolysin (SLS and SLO)

Question 27

two fungal infections of the skin

Answer 27

dermatophyte (ringworm)

candida

Question 28

what is ringworm caused by?

Answer 28

trichophyton rubrum, trichophyton mentagraphytes and microsporum canis

Question 29

diagnosis of ringworm

Answer 29

woods light

skin scraping

Question 30

management of ringworm

Answer 30

clotrimazole
topical nail paint amorolfine
for scalp- terbinafine and itraconzole

Question 31

what areas does candida tend to infect?

Answer 31

warm, moist areas

Question 32

diagnosis of candida

Answer 32

swab for culture

Question 33

management of candida

Answer 33

clotrimazole and fluconazole

Question 34

parasitic infections in the skin

Answer 34

scabies

lice

Question 35

presentation of scabies

Answer 35

all over body itch and rash, worse at night

Question 36

management of scabies

Answer 36

malathion lotion

Question 37

presentation of lice

Answer 37

intense itch

Question 38

diagnosis of lice

Answer 38

skin scraping

Question 39

management of lice

Answer 39

malathion lotion

Question 40

when should single room isolation be undertaken?

Answer 40

strep A
MRSA
scabies