Skin and Soft Tissue Infections - Etiology Flashcards
What are the two categories that SSTI’s are split into?
Purulent and Non-purulent
Purulent = pus present
What parts of the skin does cellulitis affect?
Epidermis and dermis, may spread within superficial fascia
A serious consequence of cellulitis is this complication:
Spread through lymphatic tissue and bloodstream
…But is usually self-limiting
Common S/Sx of cellulitis involving the skin include:
Affected area is hot and painful - erythema + edema of skin, inflammation (little/no necrosis)
Purulent drainage, exudates, or abscess may be involved
What patient history is common in cellulitis cases?
Antecedent minor trauma, abrasion, ulcer, or surgery
Other common symptoms involved in cellulitis infection include:
Tender lymphadenopathy
Fever, chills, malaise
Sx’s signifying a severe cellulitis infection include:
Systemic
Hypotension, dehydration, altered mental status
What are the two microorganisms involved in SSTI’s?
Group A Streptococcus
Staphylococcus aureus
Staphylococcus Aureus can be categorized into the two following groups:
MSSA - susceptible to methicillin
MRSA - not susceptible to beta-lactam antibiotics
If a patient presents with non-purulent cellulitis, what microorganism should we suspect?
Predominantly Strep (GAS)
Lower rate of staph
If a patient presents with purulent cellulitis, which organism should we suspect?
Predominantly Staph Aureus
What are the 5 C’s for MRSA risk factors?
Crowding, frequent skin contact, compromised skin, sharing of contaminated personal items, lack of cleanliness
What are some other important risk factors to consider for MRSA infections?
History of colonization/recent MRSA infection
Antibiotic use in last 6 months
IV drug use
Any occupation or lifestyle involving close contacts (correctional facilities, military, homelessness)
When should we cover for MRSA?
MRSA risk factors present
Highly endemic area for MRSA
Clinical judgement of illness, and lack of improvement on a beta-lactam
SSTI’s often respond to therapy not covering for MRSA even if it was cultured, so condition can be self-limiting
Does MRSA have any identifiable S/Sx’s from other microorganisms?
No reliable signs or symptoms of differentiation
