Microbiology

Question 1

how does the skin protect itself from microorganisms?

Answer 1

it produces sebum inhibiting bacterial growth
dry skin desiccates organisms
competitive bacterial flora

Question 2

examples of competitive bacterial flora

Answer 2

staph epidermidis
corynebacterium
propionibacterium

Question 3

five virulence factors

Answer 3

adhesin
invasin
impedin
aggressin
modulin

Question 4

define adhesin

Answer 4

enables binding of the organism to the 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

causes damage to the host indirectly

Question 9

do some people carry staph aureus on their skin?

Answer 9

yes

Question 10

virulence factors of staph aureus

Answer 10

fibrinogen binding protein
leucocidin (exotoxin that kills leucocytes)
enterotoxin (food poisoning)
TSST-1
coagulase positive (clots plasma)
PVL

Question 11

what is TSST-1

Answer 11

superantigen that produces toxins

Question 12

what does TSST-1 cause?

Answer 12

vomiting
fever
scalded skin syndrome
toxic shock syndrome

Question 13

how does TSST-1 cause damage

Answer 13

massive release of cytokines

Question 14

describe PVL (Panton-Valentine-Leukocidin)

Answer 14

this is a toxin produced by a certain strain of staph aureus that kills leucocytes

Question 15

what does PVL cause

Answer 15

furunculosis
necrotising pneumonia
necrotising fasciitis

Question 16

antibiotic of choice for staph aureus

Answer 16

flucloxacillin

Question 17

when is flucloxacillin not the antibiotic of choice for staph aureus

Answer 17

MRSA

Question 18

what group is strep pyogenes

Answer 18

group A strep

Question 19

what type of haemolysis is strep pyogenes

Answer 19

beta haemolysis

Question 20

what system is used to classify the bacterial cell wall in different types of strep?

Answer 20

Lancefield ssytem

Question 21

skin infections caused by strep pyogenes?

Answer 21

impetigo
cellulitis (erysipelas)
necrotising fasciitis

Question 22

what does impetigo present with

Answer 22

honey coloured crust

Question 23

define cellulitis

Answer 23

deeper infection of the dermis not associated with necrosis

Question 24

define necrotising fasciitis

Answer 24

destroys connective tissue with streptomycin (SLS)

Question 25

virulence factors of strep pyogenes

Answer 25

• superantigen
• haemolysins SLO and SLS
• M protein

Question 26

two types of fungal infections in the skin

Answer 26

dermatophyte (ringworm)

candida

Question 27

how does dermatophyte cause infection?

Answer 27

fungus enters soggy skin and affects keratinised tissues

Question 28

causes of dermatophyte (ringworm)

Answer 28

trichophyton rubrum, mentagraphytes and microsporum canis

Question 29

diagnosis of dermatophytosis

Answer 29

clinical appearance
woods light
skin scraping
hair/nail clippings

Question 30

management of dermatophytosis

Answer 30

clotrimazole

topical nail paint (amorolfine)

Question 31

management for scalp dermatophytosis

Answer 31

terbinafine

itraconzole

Question 32

what areas does candida infect?

Answer 32

warm, moist areas

Question 33

diagnosis of candida

Answer 33

swab for culture

Question 34

management of candida

Answer 34

clotrimazole

fluconazole

Question 35

two parasitic skin infections

Answer 35

scabies

lice

Question 36

chronic form of scabies

Answer 36

Norwegian scabies

Question 37

incubation period of scabies

Answer 37

6 weeks

Question 38

presentation of scabies

Answer 38

itchy all over body rash that is worse at night

Question 39

management of scabies

Answer 39

marathon lotion

benzyl benzoate

Question 40

presentation of lice

Answer 40

intense itch

Question 41

management of lice

Answer 41

malathion

Question 42

infection control- singe room if…

Answer 42

single room isolation if strep A, MRSA or scabies