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
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
