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Flashcards in Micro 4: skin infection Deck (91)
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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

1. 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