Bacterial and viral infections Flashcards
What are commensal bacteria and name 4 examples?
Bacteria present on skin but not causing disease
- stapylococci
- micrococci
- corynebacteria
- propionibacteria
3 mechanisms by which staphylococci can cause infection
- primary infection occurs on previously seemingly normal skin - direct invasion of epidermis
- 2ndary infection occurs in skin which has been damaged in some way already e.g. wound infection
- staphylococi produce toxins which themselves can induce disease
Where is S. aureus commensal?
In nasal canal
Name 2 topical antibiotics to treat bacterial infections?
fusidic acid
mupirocin
Name 2 oral antibiotics to treat bacterial infections?
flucloxacillin
clindamycin
3 types of primary staphylococcial infection
- impetigo
- bullous impetigo
- folliculitis
What does impetigo look like?
classic golden crust
What age group impetigo common in?
young children
How do you treat impetigo?
responds well to topical antibiotics unless infection is very widespread.
What other bacterium is impetigo sometimes caused by
streptococcal infection
Which group is bullous impetigo especially common in?
infants
Describe what folliculitis looks like
pustules around hair follicles with surrounding inflammation - red
What other test must you do with folliculitis?
nasal swab and treat with mupirocin nasal ointment if positive
How do you manage folliculitis?
short and long term
topical antibiotics
may need short course of oral flucloxacillin
if recurrent and severe may respond to a 3 month course of tetracycline/erythromycin
Name 4 types of secondary staphylococcal infection?
- wound infection
- cellulitis (may be primary)
- infected eczema
- infected leg ulcer
which types of secondary staphylococcal infection can also be caused by streptococcal infection?
cellulitis and infected eczema and infected leg ulcer
What is ecthyma?
deep infection caused by staph/strep and may be more common in immunosuppressed/ diabetes etc
How do you treat ecthyma?
longer course antibiotics - can scar
How do you treat a wound infection
oral antibiotics, remove foreign bodies such as stitches if possible, allow any puss to drain
How do you treat cellulitis
systemic antibiotics - oral or IV and check for cause such as tinea pedis
What would bilateral cellulitis suggest?
UNUSUAL as infection is unilateral and inflammation is bilateral SO would suggest a different diagnosis such as varicose eczema
How to treat an infected leg ulcer?
- potassium permanganate
- compression bandaging if appropriate once initial infection is under control
What is staphylococcal scalded skin syndrome?
rare condition in infants, may follow minor infection such as impetigo. Redness goes to peeling in flexures. Bacterial toxins damage the skin barrier
Management of staphylococcal scalded skin syndrome?
antibiotics for underlying infection IV fluclox, fluid, analgesia, emollient, may require ICU
