Skin and soft tissue infections Flashcards
ILO 1.14a: have knowledge of the causes of infection, mechanisms and routes of spread of infection and principles of treatment (22 cards)
what are the different ways to classify skin and soft tissue infections?
2
- classification by microbe
- classification by anatomy
describe S.aureus. what is its virulence factor? give an example of a disease it can cause
- round shaped = cocci
- gram positive (purple colour stain)
- clumps together
- VF = panton valentine leukocidin toxin
- can cause angular cheilitis
describe S.pyogenes (group A streptococcus). what is its virulence factor? give an example of a disease it can cause
- round shaped = cocci
- gram positive (purple colour stain)
- chains
- VF = superantigens and toxic shock syndrome
- can cause cellulitis
describe S.anginosus. what is its virulence factor? give an example of a disease it can cause
- round shape = cocci
- gram positive (purple colour stain)
- chains and clumped together
- VF = intermedilysin (cytotoxin)
- can cause periapical periodontitis
describe Clostridium welchii. what is its virulence factor? give an example of a disease it can cause
- rod shaped
- gram positive (purple colour stain)
- anaerobic
- VF = alpha toxin
- can cause gas gangrene
describe Herpes Simplex group. what is its virulence factor? give an example of a disease it can cause
- DNA virus
- nuclear capsid surrounded by lipid membrane
- VF = cell lysis
- can cause herpes labialis (cold sore)
describe candida albicans. what is its virulence factor? give an example of a disease it can cause
- larger than bacteria
- yeast cells (round)
- VF = phospholipase
- can cause erythematous candidiasis (oral thrush)
what are the different layers of the skin?
6
- epidermis
- dermis
- hair follicles
- subcutaneous fat
- fascia
- muscle
what infections can occur in the epidermis? what are they caused by?
- impetigo - S.pyogenes
- angular cheilitis - S.aureus
what infection can occur in the dermis? what is it caused by?
erysipelas - S.pyogenes
what infections can occur in the hair follicles? what are they caused by?
- folliculitis - S.aureus
- boils (furnucle) - S.aureus
- carbuncles (multiple heads) - S.aureus
what infections can occur in subcutaneous fat? what are they caused by?
- cellulitis - S.pyogenes
- periapical periodontitis - S.anginosus
what infection can occur in the fascia? what is it caused by?
necrotising fasciitis - S.pyogenes or S.aureus and anaerobes (mixed infection)
what infection can occur in muscle? what is it caused by?
myonecrosis (gangrene) - Clostridium welchii
what bacteria are surgical wounds caused by?
S.aureus
what bacteria are bite wounds from humans and animals caused by?
- humans - mixed anaerobes
- animals - Pasteurella multicoda
what are the treatment principles?
5
- diagnosis
- surgical debridement
- microbiological specimens
- antibiotocs
- review
what antibiotics are used with S.aureus (meticillin sensitive), S.aureus (meticillin resistant), S.pyogenes and S.angiosus?
- S.aureus (meticillin sensitive) - flucloxacillin
- S.aureus (meticillin resistant) - vancomycin
- S.pyogenes - penicillin
- S.angiosus - penicillin
how should you treat a localised dental abcess?
surgical treatment only
how should you treat a dental abcess with systemic signs and symptoms?
penicillin V (phenoxymethyl penicillin) and review
how should you treat a severe odontogenic infection (SOI)?
hospital based treatment including IV ben penV and metronidazole
what are the NICE guidelines for choosing antibiotics?
take into account:
* severity of symptoms
* site of infection
* risk of uncommon pathogens
* any microbial results and MRSA status if known
