IC14 SSTI Flashcards
How should cultures be taken from wound?
Should be deep in wound after surface is cleansed
Base of closed abscess
By curettage
Difference between Impetigo and Ecthyma (type of lesion, how deep)
Impetigo is clear vesicles, reach epidemis
Ecthyma is ulcer, reach dermis
Risk factors for MRSA (7 points)
Antibiotic use
Recent hospitalisation or surgery
Prolonged hospitalisation
Intensive care
Hemodialysis
MRSA colonisation
Proximity to MRSA colonised or infected patients
Likely pathogen for Impetigo or Ecthyma
Hence what is the treatment for limited / multiple lesions?
Culture directed?
How many days of therapy?
MSSA, Grp A-D strep
Limited: No treatment needed, self limiting
Multiple lesions:
Empiric therapy
PO Cephalexin or Cloxacillin
Penicillin allergy
Mild allergy
Cefuroxime (replace Cephalexin)
Severe allergy
PO Clindamycin
Culture directed (Strep A, Pyogenes)
Penicillin V
Amoxicillin
Culture directed (MSSA)
PO Cephalexin or Cloxacillin
5-7 days
What is the mainstay of treatment for purulent SSTI? (Furuncles, Carbuncles, Skin abscesses, Purulent cellulitis)
Incision and Drainage
When to use systemic antibiotics in purulent SSTI? (7 points)
Unable to drain completely
No response to I&D
Extensive disease involving several sites
Very young or very old
Immunocompromised
Signs of systemic illness (SIRS criteria)
Severe disease
Common pathogens for purulent SSTI (Furuncles, Carbuncles, Skin abscesses, Purulent cellulitis)
MSSA
Strep (grp A-C,G)
Some gram (-)
anaerobes
What is the treatment for mild, moderate, severe purulent SSTI, assuming no coverage for (-) and anaerobes
Treatment duration?
Mild infection
I&D + Warm compress to promote drainage
Moderate infection + Systemic symptoms
I&D + Oral antibiotics
Cloxacillin
Cephalexin
Penicillin allergy: Clindamycin
Severe infection
I&D + IV antibiotics
IV Cloxacillin
IV Cefazolin
Clindamycin (for allergy)
Vancomycin (for MRSA)
5-10 days
What if need empiric MRSA coverage for purulent SSTI? (oral and IV options) (3 points each)
Oral
Co-trimoxazole (but does not cover Grp A-D strep)
Doxycycline
Clindamycin
IV
Vancomycin
Daptomycin
Linezolid
Empiric gram (-), anaerobic coverage for purulent SSTI?
Amox-Clav
What are examples of non purulent STI? (2 points)
Common pathogen?
Cellulitis, Erysipelas
Grp A beta hemolytic strep (Strep Pyogenes)
How to differentiate mild, moderate and severe non purulent SSTI (Cellulitis or Erysipelas)
Mild: no systemic signs of infection
Moderate: signs of infection, some purulence
Severe: systemic signs of infection, failed oral therapy or immunocompromised + consider possibility of necrotising infections → Broad coverage: gram (+), (-), anaerobes
Coverage for mild VS moderate nonpurulent SSTI?
Hence what is the treatment?
Mild: Grp A strep
Cover: Use oral antibiotic
Penicillin V
Cephalexin
Amoxicillin
Allergy: Clindamycin
Moderate: May use IV
similar to moderate purulent SSTI
Cover: Grp A strep + MSSA
Cefazolin
Cloxacillin
(penicillin allergy) Clindamycin
If water exposure
Add Ciprofloxacin
Cover Aeromonas, Vibrio and Pseudomonas
What to cover for nonpurulent SSTI?
Treatment for severe nonpurulent SSTI
Pseudomonas, Grp A strep
IV antibiotics (cover Pseudomonas, water exposure)
Pip-Tazo
Meropenem
Cefepime
MRSA risk factor
Add IV Vancomycin, Daptomycin, Linezolid
How long should symptoms take to improve in general for SSTI
2-3 days
Why should we not use mupirocin for mild cases?
Mild cases are self limiting
Mupirocin only used for MRSA decolonisation
How does DFI occur?
1) Peripheral neuropathy
Decreased pain sensation
2) Vasculopathy
Worsened by hyperglycemia and hyperlipidemia
3) Immunopathy
Impaired immune response
Worsened by hyperglycemia
1-3 causes ulcer formation, wounds → Bacterial colonisation, penetration and proliferation → DFIs
How to tell if an wound is infected?
Purulent + 2 signs (Redness, Tenderness, Warmth, Pain, Induration- skin thicker due to inflammation)
Are cultures needed for mild, moderate, severe DFI?
Mild dont need
Criteria for Mild DFI
Cover which bugs?
Drug of choice
< 2cm erythema around ulcer
Cover (+) only (Grp A-D strep + MSSA)
Use oral drugs for Mild DFI
Use Cephalexin, Cloxacillin, Clindamycin
MRSA: Clindamycin, Doxycycline
(cotrimox has poor beta hemolytic coverage)
Moderate DFI requirement?
Need cover what?
Hence treatment?
> 2cm erythema around ulcer
(+), (-), Anaerobes
Use IV for Moderate DFI
Cefazolin + Metronidazole
Ceftriaxone + Metronidazole
Amox-Clav
MRSA: IV Vanco, Dapto, Linezolid
Requirement for Severe DFI
Need cover what?
Hence treatment?
> 2cm erythema around ulcer
Signs of systemic infection
(+), (-), Anaerobes, Pseudomonas
Treatment
Pip-Tazo
Meropenem
Cefepime + Metronidazole
Metronidazole → Anaerobes
Ciprofloxacin + Clindamycin
Ciprofloxacin → (-), Pseudomonas
Clindamycin → (+), anaerobes
Add IV MRSA if have risk factors
Duration of therapy for DFI if no bone involvement (mild, moderate, severe)
Mild: Up to 2 weeks
Moderate: Up to 3 weeks
Severe: up to 4 weeks
Duration of therapy if have bone involvement?
Amputation VS Residual infected soft tissue VS Residual viable bone VS No surgery
Amputation: Up to 5 days
Residual infected soft tissue: Up to 3 weeks
Residual viable bone: 4-6 weeks
NO surgery: > 3 months
Adjunctive measures for wound care (5 points)
Debridement
Off-loading
Reduce weight put on leg
Apply dressing to control excess exudation
Foot care
Daily inspection
Prevent wound and ulcers
Optimal glycemic control
