Micro 4: skin infection COPY Flashcards
When are skin infections more commonly seen- GP or hospital
In GP it’s 25% In hospital 5%
Where are high and low rates of skin infection seen
* High rates of skin infection are seen in hot, humid and poor populations * Low rates are see in dry, temperate conditions, and rich populations
What type of bacterium is S. Aureus
Gram pos (cocci, fro name)
What toxins does S. Aureus produce
Panton Valentine Leuocidin, Exfoliative toxin, TSST-1 (Toxic Shock Syndrome Toxin 1) ,Enterotoxin
Is S. Aureus always harmful?
COMMENSAL 30% carry it, either in the nostrils or on the ski
Which AB is it commonly resistant to
MRSA Resistant to methicillin= flucoxicillin
What can S. Aureus infect
Bone, joint, lung infections
What is the structure of the S. Aureus
Cell wall, cell membrane Susceptible to penicillin treatment
What are panto valentina leucocidin
It is a virulence factor which makes the infection necrotising (it causes tissue death)
What is the exfoliative toxin
Cuases cleavage of the skin within the epidermis . involves the same antigen as bullous pemphigus. Causes skin to flake off
What is TSST-1
Toxic shock dynfrome 1 causes septicaemia type disease
What are enterotoxin
Food handler might have infected S. Aureus and an enterotoxin can get into the good and cause D and V in others
Where can S. Aureus cause infection
Bone joint lung infections But focus of infection ften starts on the skin
When can staphylococcal lung infection occur
Often after flu (so deaths due to flue can be caused by this)
Manifestations of S. Aureus
Impetigo: subcorneal layer(i.e. very superficial) Folliculitis: mouth of hair follicle… can progress to abcess Ecthyma: full thickness involvement of the epidermis, we see an (e.g. infected insect bite) NOT IN DERMIS . A boil: An abcess that often starts in the hair follicle. A carbuncle describes multiple abscesses next to each other, all coalescing( an abcess of multiple ajoining hair follicles.)
What kind of skin infection does insect bite cause
Ecthyma …. lesions look like firmly adherent crust on a background of erythema. The crust will not come off – the surface of the skin is dying. It commonly occurs after infected insect bites, or infected wounds.
What is it called if a folliculitis forms into abscess of hair follicle
Called boil
What is a carbuncle
Abscess of several adjacent hair follicles
Which S. Aureus infections are inthe spidermis and which in the dermis
Epidermis: Impetigo, folliculitis, ecthyma (might extend a tiny bit into the dermis) Dermis: Boil and carbuncles
Feature of S. Aureus
Aureus= gold because the crust is golden
Common locatios for impetigo What is bollous impetigo
It often occurs around the nose and mouth, but can occur anywhere (particularly groin/perineal region Blistering with S. Aureus Because of the exfoliative toxin from S. Aureus (against that desmoglein antigen) in addition to the impetigo which is just infection of the subcorneum and corneum
What can abscess start off as. How is it treated
Start as folliculitis treated with pus drainage
What can the exfoliative toxin from S Auerus casue
- Bollous impetigo 2. Staphylococcal scalded skin syndrome
Who does Staphylococcal scalded skin syndrome occur in
Ages under 5 Because the immune system of children hasn’t developed properly so the infection can spread and cause widespread erythema and epithelial release
How can you confirm it
Send away for lab
What is the treatment for S. Auerus
Give flucoxicillin/clindamycin/erythromycin Topic for impetigo
What infection causes symphylis
Treponema pallidum
What type of bacterium is Treponema pallidum
Gram neg spirochete (Syph Spiro)
What is coinfection with Treponema pallidum bad
Co-infection with syphilis increases the transmission of HIV
Phases of syphilis
Primary (3-8 weeks) Secondary (6-12) Latent Tertiary Congenital
Outline primary syphilis
Painless ulcer at inoculation site (Genital or oral)
Outline secondary syphilis
Disseminated infection Generalised rash and lymphadenopathy
Outline latent syph
(no clinical signs)
Outline teriary syph
Skin, neurological and vascular manifestations
Outline congenital syph
Acquired perinatally ( can cause miscarraiges|)Early and late manifestations
What happens to the baby in congenital syph
Miscarriage Still birth Prematurity Rashes Brain and neurological problems Bone disease