SSTIs Flashcards
Pathogens causing impetigo?
Staph
Strep
Bullous form -> toxin-producing strains of S. aureus
Tx for impetigo?
- Mild, limited lesions
- Mild, limited lesions
Topical mupirocin BD x 5d
Tx for impetigo?
- Multiple lesions
- Multiple lesions (same as Tx for ecthyma)
Treat for 5-7 days
Empiric: PO cloxacilin, PO cephalexin, PO cefuroxime (mild penicillin allergy), or clindamycin (severe penicillin allergy)
Culture directed:
Strep pyogenes- PO Pen V, PO amoxiciilin
MSSA- PO cephalexin, PO cloxacillin
Pathogens causing nonpurulent Cellulitis and Erysipelas?
- Mainly beta-hemolytic strep (usually strep A pyogenes)
- S. aureus (less frequent)
- Less common, based on risk factors: Aeromonas, Vibrio vulnificus, Pseudomonas
What pathogens must you cover for MILD nonpurulent Cellulitis and Erysipelas?
What does mild mean?
What type of abx must you use (route)?
Cover S. pyogenes
Mild: without systemic s/sx
Use PO abx
Tx for MILD nonpurulent Cellulitis and Erysipelas?
Treat for 5-10 days, 14 days if immunocompromised
- PO Pen V
- PO Cephalexin
- PO Cloxacillin
- Penicillin allergy: PO clindamycin
What pathogens must you cover for MODERATE nonpurulent Cellulitis and Erysipelas?
What does moderate mean?
What type of abx must you use (route)?
Cover MSSA
Moderate: Systemic s/sx with some purulence
May use IV abx (depends on clinical judgement)
Tx for MODERATE nonpurulent Cellulitis and Erysipelas?
Treat for 5-10 days, 14 days if immunocompromised
- IV cefazolin
- PO/IV cloxacillin
- Penicillin allergy: PO/IV clindamycin
If water exposure: Add PO/IV ciprofloxacin
What pathogens must you cover for SEVERE nonpurulent Cellulitis and Erysipelas?
What does severe mean?
What type of abx must you use (route)?
Broader coverage*, consider possibility of necrotising infections (more gram -ve)
Severe means systemic s/sx, failed PO Tx or immunocompromised
IV abx
Tx for SEVERE nonpurulent Cellulitis and Erysipelas?
If MRSA risk factors?
Treat for 5-10 days, 14 days if immunocompromised
- IV piperacillin-tazobactam
- IV cefepime
- IV meropenem
IF MRSA risk factors: add IV vancomycin, daptomycin, linezolid
What are some non-pharmacological Tx for SEVERE nonpurulent Cellulitis and Erysipelas?
- Ensure rest, limb elevation
- Treat underlying conditions
What pathogens must you cover for purulent (furuncles, carbuncles, skin abscesses, cellulitis)?
What about pts with skin abscess involving perioral, perirectal and vulvovaginal areas?
S. aureus (main)
Some Beta-hemolytic strep
If skin abscess involving perioral, perirectal and vulvovaginal areas: cover Gram -ve AND anaerobes
What is the mainstay treatment of purulent SSTI?
Incision and drainage (I&D)
When do you add on systemic abx for purulent SSTI? (6 points)
Add if:
- Unable to drain completely
- No response to I&D
- Extensive disease involving several sites
- Extreme age
- Immunosuppressed (chemoTx, transplant)
- Systemic s/sx (at least 2 of SIRS Criteria)
Name the SIRS Criterias (4)
- Temp > 38°C or < 36°C
- HR > 90 bpm
- RR > 24 bpm
- WBC > 12 x 10^9/L or < 4 x 10^9/L
Tx for MILD purulent SSTI?
I&D or warm compress to promote drainage
Tx for MODERATE purulent SSTI?
I&D + PO abx
- PO Cloxacillin
- PO Cephalexin
- PO Clindamycin if penicillin allergy
Tx for SEVERE purulent SSTI?
I&D + IV abx
- IV Cloxacillin
- IV Cefazolin
- IV Clindamycin
- IV Vancomycin (MRSA cover)
If a patient with purulent SSTI has MRSA risk factors, what is the empiric Tx for MRSA?
- PO co-trimoxazole
- PO doxycycline
- PO clindamycin
- IV vancomycin (FIRST-LINE)
- IV daptomycin ($$)
- IV linezolid ($$)
If a patient has purulent SSTI with skin abscess involving perioral, perirectal and vulvovaginal areas, we need to cover gram- ve and anaerobes, so what is the empiric Tx?
Amoxicillin-clavulanate
What are the risk factors for CA-MRSA? (7 points)
Risk factors:
- Contact sports
- Military personnel
- IV drug abusers
- Prison inmates
- Overcrowded facilities
- Close contact
- Lack of sanitation
How do you define HA-MRSA and what are the risk factors? (7 points)
HA-MRSA is MRSA that occurs
- > 48h after hospitalisation
- Outside of hospital within 12m of exposure to healthcare
Risk factors:
- Abx use
- Recent hospitalisation/ surgery
- Prolonged hospitalisation
- ICU
- Hemodialysis
- MRSA colonization
- Proximity to others with MRSA colonisation/ infection
How do you classify DFI as an infection?
Purulent discharge OR at least 2 s/sx of inflammation:
- Erythema
- Warmth
- Tenderness
- Pain
- Induration
What are the likely pathogens for DFI?
Name the gram +ve, gram -ve and anaerobes.
When do you see gram -ve and anaerobic pathogens?
Gram +ve:
- S. aureus
- Beta hemolytic strep
Gram -ve:
Particularly in chronic wounds/ wounds previously treated with abx
- E coli., Klebsiella, Proteus spp
Anaerobes:
Particularly in ischemic/ necrotic wounds
- Peptostreptococcus spp
- Veillonella spp
- Bacteroides spp
For DFI empiric Tx, when do you need to cover for P. aeruginosa?
When severe infection and/ or failure of abx (that was not active against P. aeruginosa)
Describe how you would classify a MILD DFI?
- Infection of skin and SC tissue and
- Erythema ≤ 2cm around ulcer
- NO systemic s/sx of infection
What are the organisms to cover for MILD DFI?
Strep spp, S. aureus
Tx for MILD DFI?
If need MRSA coverage, what to use?
- PO cephalexin
- PO cloxacillin
- PO clindamycin
If MRSA coverage needed, use:
- PO co-trimoxazole
- PO clindamycin
- PO doxycycline
Describe how you would classify a MODERATE DFI?
- Infection of deeper tissue (eg bone, joints) OR
- Erythema > 2cm around ulcer
- NO systemic s/sx of infection
What are the organisms to cover for MODERATE DFI?
Strep spp, S. aureus
Gram -ve (+/- P. aeruginosa) - depends on risk factors for P. aeru
Anaerobes
Tx for MODERATE DFI?
If need MRSA coverage, what to use?
IV abx (if no need P. aeruginosa cover):
- IV amoxicillin-clavulanate
- IV cefazolin/ ceftriaxone + metronidazole
If MRSA coverage needed, add:
- IV vancomycin
- IV daptomycin
- IV linezolid
Describe how you would classify a SEVERE DFI?
- Infection of deeper tissue (eg bone, joints) OR
- Erythema > 2cm around ulcer AND
- Systemic s/sx
What are the organisms to cover for SEVERE DFI?
Strep spp, S. aureus
Gram -ve (P. aeruginosa)
Anaerobes
Tx for SEVERE DFI?
If need MRSA coverage, what to use?
IV abx:
- IV piperacillin-tazobactam
- IV cefepime + metronidazole
- IV meropenem
- IV ciprofloxacin + clindamycin
If MRSA coverage needed, add:
- IV vancomycin
- IV daptomycin
- IV linezolid
If no bone is involved, what is the recommended Tx duration for mild, moderate and severe each?
NO bone involved:
Mild- 1-2w
Moderate- 1-3w
Severe- 2-4w
If the bone is involved, what is the recommended Tx duration for:
- Surgery (amputation- ALL removed)
- Surgery- residual infected soft tissue
- Surgery- residual viable bone
- No surgery/ surgery- residual dead bone
- Surgery (amputation- ALL removed)
2-5 days - Surgery- residual infected soft tissue
1-3w - Surgery- residual viable bone
4-6w - No surgery/ surgery- residual dead bone
≥ 3m
