SSTI Flashcards
Name the SIRS (systemic inflammatory response syndrome) criteria, which is correlated to signs of systemic infection
At least 2 of the following: fever > 38 degrees, tachycardia > 90 bpm, tachypnea > 24 bpm, WBC > 12 x 10^9 or < 4 x 10^9,
Name the risk factors for the development of SSTIs
Disruption of the skin barrier: traumatic (lacerations, recent surgery, burns, abrasions, crush), non-traumatic (ulcers, tinea pedis, dermatitis, toe web-intertrigo, chemical irritants)
Impaired venous and lymphatic drainage: saphenous venectomy, obesity, chronic venous insufficiency
Peripheral artery disease
Immunocompromised: diabetes, HIV, cirrhosis, neutropenia, taking immunosuppresive medications
History of cellulitis
Name the prevention methods for SSTIs
Good wound care
Acute traumatic wounds should be copiously irrigated, foreign object removed and devitalized tissue debrided
Good foot care for DM patients, including daily inspection
Optimal glycemic control for DM patients
Treatment of tinea pedis
Preventing dry and cracked skin
(for pressure ulcers) return/re-position patient every 2 hours
List the different types of SSTI and their clinical presentations
Impetigo: infection of the epidermis, starts with erythematous papules that evolve into pustules or vesicles, dried discharge later forms honey-coloured crust over erythematous base
Ecthyma: infection extends into the dermis, ulcerative form of impetigo: ‘punched out’ looking ulcers; pruritis is common and scratching may further spread the infection
Furnucle: infection of the hair follicle, purulent material extends through the dermis to the subcutaneous tissue, where a small abscess forms
Carbuncle: formed when furnucles coalesce and extend into the subcutaneous tissue
Skin/cutaneous abscess: collection of pus within and beyond the dermis; manifests as painful, tender, fluctuant and erythematous nodules
Erysipelas: infection of the lymphatics in the dermis; presents as fiery red/erythematous, tender, painful plaques (raised above surrounding skin), with well-demarcated edges
Cellulitis: infection of the subcutaneous tissue; presents as acute, diffuse, spreading, non-elevated, poorly demarcated area of erythema, with rapid onset/progression; almost always unilateral; fever present in 20-70% of patients
When to take culture for SSTIs?
Purulent: moderate, severe cases
Non-purulent: severe cases
DFI: optional for mild, yes for moderate, yes for severe cases
How to take pus/exudate/tissue culture for SSTIs?
Take culture from deep in the wound after the surface is cleansed,
Take culture from the base of a closed abscess, where bacteria grow
Take culture by curettage (tissue debridement), rather than wound swab
When to take blood culture for SSTIs?
Non-purulent and purulent: severe cases (marked systemic symptoms and/or refractory to oral treatment and/or immunocompromised patients)
Define HA-MRSA (healthcare-associated MRSA)
HA-MRSA is an MRSA infection that occurs >48h following hospitalization or outside of the hospital within 12 months of exposure to healthcare
Name the risk factors for HA-MRSA (healthcare associated MRSA)
Recent antibiotic use in the past 3-6 months, recent hospitalization or surgery in the past 3 to 6 months, prolonged hospitalization, hospitalization in ICU, patient undergoing hemodialysis, patient with MRSA colonization, close proximity to others with MRSA colonization or infection
Describe the various categories of SSTI (incl. DFI/pressure ulcers)? and the likely pathogens to cover for?
Mild impetigo: S. aureus, S. pyogens
Moderate/severe impetigo and ecthyma: S. aureus, S. pyogens
Purulent:
- mild (no systemic symptoms): S. aureus
- moderate (systemic symptoms): S. aureus, consider MRSA, consider gram neg/anaerobes
- severe (systemic symptoms, marked): S. aureus, consider MRSA, consider gram neg/anaerobes
Non-purulent
- mild (no systemic symptoms): S. pyogenes
- moderate (systemic symptoms, some purulence): S. pyogenes, S. aureus
- severe (systemic symptoms, immunocompromised, refractory to oral therapy): S. pyogenes, S. aureus, Pseudomonas, consider MRSA
DFI/pressure ulcers
- mild (dermis/subcutaneous, erythema =<2cm around the ulcer, no signs of systemic infection): S. aureus, S. pyogenes, consider MRSA if risk factors
- moderate (bone/joints, erythema > 2cm around the ulcer, no signs of systemic infection): S. aureus, S. pyogenes, Gram-negative, Anaerobes, consider MRSA, consider Pseudomonas
- severe (bone/joints, erythema >2cm around the ulcer, signs of systemic infection): S. aureus, S. pyogenes, Gram-negative, Anaerobes, Pseudomonas, consider MRSA
Describe the empiric antibiotic regime and culture-directed regime for impetigo and ecthyma
Empiric:
Mild impetigo:
- topical mupirocin 2% ointment BD x 5 days
Moderate/severe impetigo:
- Cloxacillin PO 500mg-1g q6h x 5-7 days
- Cephalexin PO 500mg q6h x 5-7 days
- Clindamycin PO 300-450mg q6h x 5-7 days
Culture directed:
S. aureus:
- Cloxacillin PO 500mg-1g q6h x 5-7 days
- Cephalexin PO 500mg q6h x 5-7 days
- Clindamycin PO 300-450mg q6h x 5-7 days
S. pyogenes:
- Penicillin V PO 500mg q6h x 5-7 days
- Amoxicillin PO 500mg-1g q8h x 5-7 days
- Cephalexin PO 500mg q6h x 5-7 days
- Clindamycin PO 300-450mg q6h x 5-7 days
Describe the empiric antibiotic regime for purulent SSTI (furuncles, carbuncles, skin abscess)
Purulent SSTI
Mild (no systemic symptoms):
- Antibiotics not needed, I&D sufficient
Moderate (systemic symptoms):
- Cloxacillin PO 500mg-1g q6h x 5-10 days
- Cephalexin PO 500mg q6h x 5-10 days
- Clindamycin PO 300-450mg q6h x 5-10 days
cover for MRSA if risk factors present, change to:
- Co-trimoxazole PO 800/160mg BD x 5-10 days
- Doxycycline PO 100mg BD x 5-10 days
- Clindamycin PO 300-450mg q6h x 5-10 days
cover for gram neg/anaerobes if skin abscess is near the peri-oral/peri-rectal/vulvovaginal area, change to/add on:
- Amoxicillin-clavulanate PO 625mg TDS
Severe (marked systemic symptoms):
- Cloxacillin IV 500mg-1g q4-6h x 5-10 days
- Cefazolin IV 1-2g q8h x 5-10 days
- Clindamycin IV 600mg q8h x 5-10 days
cover for MRSA if risk factors present, change to:
- Vancomycin IV 15mg/kg q8-12h
- Daptomycin IV 4-6mg/kg q24h
- Linezolid IV 600mg q12h
cover for gram neg/anaerobes if skin abscess is near the peri-oral/peri-rectal/vulvovaginal area; change to/add on:
- Amoxicillin-clavulanate IV 1.2g q6-8h
Describe the empiric antibiotic treatment regime for non-purulent SSTI?
Non purulent:
Mild (no systemic symptoms):
- Penicillin V PO 500mg q6h x 5-10 days
- Amoxicillin PO 500mg-1g q8h x 5-10 days
- Cephalexin PO 500mg q6h x 5-10 days
- Clindamycin PO 300-450mg q6h x 5-10 days
Moderate (systemic symptoms, some purulence):
- Cloxacillin IV 500mg-1g q4-6h x 5-10 days
- Cefazolin IV 1-2g q8h x 5-10 days
- Clindamycin IV 600mg q8h x 5-10 days
Severe (systemic symptoms, refractory to oral therapy, immunocompromised):
- Piperacillin-tazobactam IV 4.5g q6-8h x 5-10 days
- Cefepime IV 2g q8h x 5-10 days
- Meropenem IV 1g q8h x 5-10 days
- Ciprofloxacin IV 400mg q8-12h + Clindamycin IV 600mg q8h x 5-10 days
cover for MRSA if risk factors, add on:
- Vancomycin IV 15mg/kg q8-12h
- Daptomycin IV 4-6mg/kg q24h
- Linezolid IV 600mg q12h
14 days of treatment may be needed for immunocompromised
Describe the empiric treatment regime for diabetic foot infections/pressure ulcers
DFI/pressure ulcers
Mild (dermis/subcutaneous tissue, erythema =<2cm around the ulcer, no systemic signs of infection):
- Cloxacillin PO 500mg-1g q6h
- Cephalexin PO 500mg q6h
- Clindamycin PO 300-450mg q6h
consider MRSA if risk factors, change to:
- Co-trimoxazole PO 800/160mg BD
- Doxycycline PO 100mg BD
- Clindamycin PO 300-450mg q6h
Moderate (bone/joints, erythema >2 cm around the ulcer, no systemic signs of infection):
- Amoxicillin-clavulanate IV 1.2g q6-8h
- Cefazolin IV 1-2g q8h + Metronidazole IV 500mg q8h
consider MRSA if risk factors present, add on/change to:
- Vancomycin IV 15mg/kg q8-12h
- Daptomycin IV 4-6mg/kg q24h
- Linezolid IV 600mg q12h
consider Pseudomonas if risk factors present, add on/change to:
- Piperacillin-tazobactam IV 4.5g q6-8h
- Meropenem IV 1g q8h
- Cefepime IV 2g q8h + Metronidazole IV 500mg q8h
- Ciprofloxacin IV 400mg q8-12h + Clindamycin IV 600mg q8h
Severe (bone/joints, erythema >2cm around the ulcer and systemic signs of infection):
- Piperacillin-tazobactam IV 4.5g q6-8h
- Meropenem IV 1g q8h
- Cefepime IV 2g q8h + Metronidazole IV 500mg q8h
- Ciprofloxacin IV 400mg q8-12h + Clindamycin IV 600mg q8h
consider MRSA if risk factors, add:
- Vancomycin IV 15mg/kg q8-12h
- Daptomycin IV 4-6mg/kg q24h
- Linezolid IV 600mg q12h
Describe the risk factors for pseudomonas moderate diabetic foot infections (severe diabetic foot infection already empirically covers)?
chronic wound, wet wound, necrotizing wound
