Microbiology and the Skin Flashcards
Which organism is responsible for Staphylococcal Scalded Skin Syndrome (SSSS)?
S. aureus
When Staphylococcal Scalded Skin Syndrome occurs in a newborn, what is the name of the condition?
Ritter’s disease of the newborn
Which type of patient is most at risk of Staphylococcal Scalded Skin Syndrome?
- Children < 6 years
- Immunosuppressed
- Renal failure
How does Staphylococcal Scalded Skin Syndrome present?
- Widespread formation of fluid filled blisters
- Blisters are thin walled and Nikolsky’s sign +ve
- Widespread painful erythroderma
Which areas of the skin are most affected by Staphylococcal Scalded Skin Syndrome?
- Face
- Perineal region
- Areas where skin rubs together
How is Staphylococcal Scalded Skin Syndrome different from Toxic epidermal necrolysis?
Staphylococcal Scalded Skin Syndrome spares the mucous membranes
What is the antibiotic of choice against S. aureus?
Flucloxicillin
How many types of necrotising fasciitis exist?
2
What causes type 1 necrotising fasciitis?
Aerobic or anaerobic bacteria
When is type 1 necrotising fasciitis most frequently seen?
Post surgery
What causes type 2 necrotising fasciitis?
Group A streptococcal species
(e.g. Strep. pyogenes)
Why is Nikolsky’s sign negative in necrotising fasciitis?
Infection spreads into the subcutis and underlying muscle tissue
What is a classic sign of necrotising fasciitis on plain X-ray?
Crepitus
(gas produced by bacteria)
Why is surgery the only option for necrotising fasciitis?
- Treatment is required quickly and surgical debridement is necessary
- There is poor vascualr network due to tissue destruction for antibiotics will not be able to penetrate
(IV antibiotics will still be given with surgery, but never alone)
What are the treatments for candida intertrigo?
- Clotrimazole cream
- Nystatin
- Oral fluconazole
What is candida intertrigo?
Candidal fungal infection often seen in skin folds
(e.g. under breasts, groin areas, abdominal folds, nappy areas)
Which microorganism causes toxic shock syndrome?
S. aureus
Why is Toxic shock syndrome associated with young women?
It is associated with the use of high absorbancy tampon use
Which type of rash is associated with toxic shock syndrome?
Diffuse scarlatiniform rash which later desquamates
(clearly present on palms and soles)
Where does the rash associted with toxic shock syndrome normally manifest?
- Palms and soles
- Accentuation in skin folds
- Inguinal folds/perineal area
What are the main symptoms of toxic shock syndrome?
- Hypotension
- Shock
- Hyperaemia of mucous membranes
- Pharyngitis
- Strawberry tongue
- Skin/muscle tenderness
- Oedema of hands/feet
What is dermatophyte infection?
Fungal infection causing ringworm
By which three methods is dermatophyte infection diagnosed?
- Clinical appearance
- Skin scaping s and culture
- Woods light
Which group of Streptococcus is associated with neonatal meningitis?
B
What is Mucormycosis?
Any fungal infection in the order Murcorales
Characterised by hyphae growing in and around blood vessels
In which patients may Mucormycosis be life threatening?
- Diabetic
- Immunocompromised
What do dermatophytes require for growth?
Keratin
How is an infection with sarcoptes scabiei treated?
- Benzyl benzoate (adults, not children)
- Malathion lotion (applied overnight and washed off)
Strep. pyogenes can be treated with which antibiotics?
Flucloxicillin or penicillin
In diabetic patients with severe leg ulcers, what treatment should be given for anaerobic cover?
Metronidazole
Which bacterial species is known to cause UTIs in women of child bearing age?
Staph. saprophyticus
Tinea pedis affects which part of the body?
Fungal infection of the foot
(athletes’ foot)
Which resident bacterial species is associated with acne and is present on the upper arm and axillae?
Proprionobacterium
Which group of Strep is associated with throat/skin infections?
A
Strep pneumoniae and Strep viridans are ______ haemolytic
Strep pneumoniae and Strep viridans are alpha haemolytic
MRSA cannot be treated with which common antibiotic?
Flucloxicillin
Which bacterial species causes impetigo?
S. aureus
Which toxins are associated with S. aureus and which disease does each cause?
- Enterotoxin - food poisoning
- SSST - Staphylococcal scalded skin syndrome
- Panton valentine leukocidin - associated with MRSA
Commensals of the bowel are usually _____ haemolytic
Commensals of the bowel are usually non haemolytic
Which treatments are suitable for skin/nail involvement in dermatophyte infection?
- Amorolfine (topical nail paint)
- Clotrimazole (cream)
Which treatments are suitable for scalp involvement in dermatophyte infection?
- Oral terbinafine
- Oral itraconazole
What is the most common organism to cause tinea fungal infections?
Trichophyton rubrum
(Trichophyton mentagraphytes, second most common)
What is the classic appearance of a lesion induced by a tinea fungal infection?
Ring appearance
(due to lesion growing outwards and healing in the centre)
Which gender is more commonly affected by tinea fungal infections?
Males
