SSTI Flashcards
(46 cards)
How can SSTIs be prevented?
- Focus on managing predisposing risk factors
- Good care to maintain skin integrity eg good wound care, treating tinea pedis, preventing dry cracked skin, good foot care for DM patients to prevent wounds and ulcers
- Predisposing factors should be identified and treated at the time of initial diagnosis to decrease recurrence
- Copiously irrigate acute traumatic wounds, remove foreign objects, and debride devitalised tissues
When are cultures required for SSTIs?
Once patient has systemic symptoms (moderate severity or worse)
Where should a skin wound culture be taken from?
- From deep in the wound after cleaning the surface
- From base of a closed abscess, where bacteria grows
- By curettage, rather than wound swab or irrigation
What is the empiric regimen for mild impetigo?
TOP Mupirocin BD x 5/7
What are the empiric regimens for impetigo or ecthyma, when there are multiple lesions?
PO cephalexin or cloxacillin
PO clindamycin
Both used to cover MSSA and Streptococci, for 7 days
What is the culture-directed therapy choice for impetigo or ecthyma that tests positive for Streptococcus pyogenes?
PO Penicillin V or amoxicillin for 7/7
What is the culture-directed therapy choice for impetigo or ecthyma that tests positive for MSSA?
PO cephalexin or cloxacillin for 7/7
When are antibiotics indicated for purulent SSTIs?
- Unable to drain completely
- Lack of response to I&D
- Extensive disease involving several sites
- Extremes of age (weak immune system)
- Immunosuppressed (chemo, transplant etc)
- Severe disease
- Signs of systemic illness
What is the treatment choice for mild purulent lesions?
I&D or warm compress to promote drainage
What is the treatment choices for moderate purulent lesions?
I&D + PO Abx (cloxacillin or cephalexin or clindamycin) for 5-10 days
Clindamycin is used if patient has penicillin allergy
What are the treatment choices for severe purulent lesions?
I&D + IV Abx (cloxacillin or cefazolin or clindamycin or vancomycin) for 5-10 days
Vancomycin used only if patient has allergy to the other 3, or has MRSA risk factors
What are the outpatient treatment choices for potential MRSA SSTIs?
PO Clindamycin, Doxycycline or Co-trimoxazole for 5-10 days
What are the inpatient treatment choices for potential MRSA SSTIs?
IV Vancomycin, Linezolid, Daptomycin for 5-10 days (Vancomycin usually used, other 2 are expensive)
What is the empiric regimen for SSTIs likely caused by gram negatives and/or anaerobes?
PO augmentin for 5-10 days
(if there is risk of resistance, can consider pip-tazo)
What is the empiric regimen for mild non-purulent SSTIs?
PO Penicillin V, cephalexin, cloxacillin for 5-10 days - mainly cover Streptococcus pyogenes
Can use clindamycin if allergic to penicillin
What is the empiric regimen for moderate non-purulent SSTIs?
IV Cefazolin or cloxacillin for 5-10 - to cover S.pyogenes and MSSA
Can use clindamycin if allergic to penicillin
What is the empiric regimen for severe non-purulent SSTIs?
IV Abx for 5-10 days: pip-tazo, cefepime, meropenem
If MRSA risk factors: add IV vancomycin, daptomycin or linezolid
When would improvement in SSTI after initiating antibiotics be expected by?
48-72h
If it takes any longer, reassess indication and/or choice of Abx
Are repeat bacterial cultures required for SSTIs?
No, as long as patient responds
What is mupirocin effective against?
- Highly effective against aerobic gram-positive cocci (esp S. aureus – 2% is bactericidal to it)
- Not effective against enterococci and gram negatives
- Useful for eradication of nasal staphylococcal carriage
What is the pathophysiology of diabetic foot infections?
→ Peripheral neuropathy: ↓pain sensation and altered pain response
→ Motor neuropathy: muscle imbalance
→ Autonomic neuropathy: ↑dryness, cracks and fissures
→ Early atherosclerosis, Peripheral vascular disease, worsened by hyperglycemia and hyperlipidemia
→ Impaired immune response increases susceptibility to infections, worsened by hyperglycemia
Results in ulcer or wound formation, which get colonized by bacteria, bacteria penetrate and proliferate to result in DFI
What is the criteria to consider a DFI to be infected?
Purulent discharge AND
≥2 signs or symptoms of inflammation: erythema, warmth, tenderness, pain, induration (thickening or hardening of the skin)
What are the possible causative pathogens of diabetic foot infections?
- Typically polymicrobial
- Staphylococcus aureus and Streptococcus spp most common
- Gram negatives: particularly if chronic or previously treated w Abx (E.coli, Klebsiella spp, Proteus spp; Pseudomonas aeruginosa less common)
- Anaerobes (Particularly in ischaemic or necrotic wounds; Peptostreptococcus spp, Veillonella spp, Bacteriodes spp)
What features of a DFI would classify it as a mild DFI?
Infection of skin and SC tissue AND
Erythema ≤ 2cm around ulcer AND
No systemic infection signs
