Skin and Soft Tissue Infections Flashcards
Cellulitis
Inflammation of the skin and subcutaneous tissues due to infection and involves deeper dermis and subcutaneous fat
Erysipelas
Inflammation due to infection that involves the upper dermis and superficial lymphatics
What are the clinical signs of cellulitis?
Signs are variable but can include:
- Redness
- Warmth
- Swelling
- Pain
- Fever
What is the cause of cellulitis?
Break in the skin leading to penetration and entry of pathogens
What are some risk factors of cellulitis?
– Edema / water retention – Skin conditions – Immunosuppression – Diabetes – Trauma
What are the most common pathogens in cellulitis?
- Strep pyogenes
- Staph aureus (both MSSA and MRSA)
Uncommon causes due to Gram negatives and bacteria from cat, dog and human bites.
How are Strep organized?
Chains
How are Staph organized?
Clusters
Purulent Cellulitis
Cellulitis associated with purulent drainage or exudate in absence of drainable abscess
What pathogen is purulent cellulitis common with?
MRSA
Non-purulent Cellulitis
Cellulitis with no purulent drainage, exudate, abscess
What pathogens are non-purulent cellulitis common with?
- Strep
- MSSA
What gives S. aureus methicillin resistance?
mecA gene
- it produces the pencillin binding protein 2a which binds to beta lactam antibiotics and confers resistance as it prevents the ringlike structure of penicillin‐like antibiotics to bind to the enzymes that help form the cell wall of the bacterium
What distinguishes CA from HA MRSA infections?
The SCCmec gene is different between the organisms
What are the risk factors for diabetic foot ulcers?
- Neuropathy • Poor sensation • Often leads to breaks in skin that go unnoticed - Peripheral vascular disease • Poor circulation