Skin and soft tissue infections

Question 1

How can skin and soft tissue infections be classified

Answer 1

By microbe

• bacteria
• virus
• fungi

By anatomy

• superficial
• deeper tissues

Question 2

Basic description of s.aureus

Answer 2

Gram positive cocci. About 20-30% of us carry

Question 3

Example of virulence factor for s. aureus

Answer 3

Panton Valentine Leukocidin (PVL) toxin - toxin which targets white cells. In epithelial cells they puncture membrane, also through polymorphs causing tissue necrosis

Question 4

Disease caused by s.aureus

Answer 4

Pyogenic:
Boils, carbuncles
Wound infections
Abscesses
Impetigo
Mastitis
Pneumonia
Endocarditis
Bacteraemia
Osteomyelitis

Toxin mediated:
Scalded skin syndrome
Toxic shock syndrome
Food poisoning

Question 5

basic description of Strep. pyogenes

Answer 5

Gram positive chains. Beta haemolysis

Question 6

virulence factor of strep. pyogenes

Answer 6

superantigens (effect is disproportionate to amount of antigen present, can bypass controls we have in place to stop overreaction) which is responsible for TSS

Question 7

disease caused by strep. pyogenes

Answer 7

TSS

Question 8

Basic description of strep. angionsus

Answer 8

gram positive chains

Question 9

virulence factor for strep. anginosus

Answer 9

intermediysin (cytotoxin)

Question 10

Disease for strep. anginosus

Answer 10

dental abscess

Question 11

Basic description for anaerobes

Answer 11

gram positive rods (bacilli) e.g. clostridium sp

Question 12

virulence factor for anaerobes

Answer 12

alpha toxin (lecithinase)
- breaks down membranes

Question 13

virulence factor for herpes simplex group

Answer 13

something which causes cell lysis (find out)

Question 14

disease caused by herpes simplex group

Answer 14

genital herpes
neonatal herpes
herpes keratitis

Question 15

Basic description of Candida albicans

Answer 15

Yeast cells, hypae (about 10x bigger than bacteria)

Question 16

Virulence factor for candida albicans

Answer 16

phospholipase (breaks down cell membranes)

Question 17

disease caused by candida albicans

Answer 17

candidiasis

Question 18

What diseases would you get on the epidermis (most outer layer)

Answer 18

• impetigo
• angular cheilitis
• chicken pox
• shingles

Question 19

What causes diseases on the epidermis

Answer 19

group A strep
staph aureus
V zoster (chicken pox/shingles)

Question 20

What diseases would you get on the dermis

Answer 20

• erysipelas (superficial form of cellulitis)
• folliculitis (in hair follicles)
• boils (furuncle deep seated infection)
• carbuncles (deep seated infection with multiple heads)

Question 21

difference between boil and carbuncle

Answer 21

boil = furuncle deep seated infection

carbuncle = deep seated infection with multiple heads

Question 22

what infections can you get in subcutaneous fat

Answer 22

cellulitis

Question 23

what infections can you get in fascia

Answer 23

necrotising fasciitis (need ab’s and surgery)

Question 24

what infections can you get in the muscle

Answer 24

• myonecrosis

- gangrene

Question 25

common cause of surgical wounds?

Answer 25

s. aureus

Question 26

common cause of human bite wounds

Answer 26

mixed anaerobes

Question 27

common cause of animal bite wounds

Answer 27

pasteurella multicoda

Question 28

Treatment principles of skin and soft tissue infections?

Answer 28

• diagnosis
• surgical debridement
• antibiotics
• review