EXAM 3 SSTI/DFI Flashcards
SSTI risk factors
Hx of SSTI, PAD, IV drug use, CKD, DM
SSTI complications
ulcers, bacteremia, endocarditis, osteomyelitis, sepsis
staph is the most common bug on the skin
types of SSTIs
non-purulent
purulent
necrotizing fasciitis
non-purulent SSTI presentation
No PUS
tender, erythema, swelling, warm to touch
Orange peel like skin
non-purulent SSTI diagnosis
cultures: skin/blood not routinely done bc skin likely contaminated
blood cultures recommended if: immunocompromised, severe infection, animal bite
imaging:
CT/MR imaging to rule out necrotizing fasciitis
non-purulent + purulent SSTI classifcation
mild: no systemic symptoms
moderate: systemic symptoms of infection
severe: meet SIRS criteria
SIRS criteria
temp > 38C
HR >90 bpm
RR > 24 bpm
WBC > 12K or <4K
non-purulent SSTI causative pathogens
streptococcus spp
MRSA: if penetrating trauma, MRSA elsewhere, nasal colonization, SIRS, failed non-MRSA ABX regimen
Non-purulent SSTI treatment - Mild
Oral ABX:
Penicillin VK
Cephalosporin
Dicloxacillin
Clindamycin
Non-purulent SSTI treatment - moderate
IV ABX:
Penicillin
Ceftriaxone
Cefazolin
Clindamycin
Non-purulent SSTI treatment - Severe
emergent surgical inspection or debridement:
Empiric ABXs:
Vancomycin + piperacillin/tazobactam
Then culture susceptibility:
Narrow based on culture and susceptibility
Purulent SSTI characteristics
Abscesses: pus within dermis and deeper skin tissue
Furuncles (boils): small abscess that formation of the hair follicle
Carbuncles: infection involving several follicles
Purulent SSTI presentation
PUS
tender, red nodules, erythema, warm to touch
Purulent SSTI
diagnosis
Cultures: wound cultures are recommended for all abscesses, carbuncles and patients with systemic sign of infection regardless of severity
Imaging: CT/MR imaging to confirm presence of abscess
purulent SSTI pathogens
MRSA
MSSA
Streptococcus spp.
how long is treatment for non-purulent + purulent SSTIs?
minimum: 5 days
Purulent SSTI treatment - mild
Incision + drainage
only treatment
Purulent SSTI treatment - moderate
incision + drainage
culture + susceptibility
empiric ABX:
sulfamethoxazole/trimethoprim
doxycycline
targeted ABX:
MRSA: sulfamethoxazole/trimethoprim or doxycycline
MSSA: dicloxacillin or cephalexin
Purulent SSTI treatment - severe
incision + drainage
culture + susceptibility
empiric ABX:
vancomycin
daptomycin
linezolid
targeted:
MRSA: vancomycin, daptomycin, linezolid
MSSA: nafcillin, cefazolin, clindamycin
Necrotizing Fasciitis characteristics
Medical emergency associated with morbidity and mortality
Necrotizing Fasciitis presentation
systemic toxicity
change in color of skin to maroon/purple/black
crepitus
edema
severe pain
Necrotizing Fasciitis diagnosis
cultures:
blood cultures recommended given severity of infection
wound cultures likely obtained from surgery
imaging:
Ct/MR imaging to confirm necrotizing fasciitis or presence of abscess –> looking for gas
necrotizing fasciitis treatment
surgery until spreading stops + broad spectrum antibiotics
Empiric therapy:
Vancomycin + piperacillin/tazobactam
Targeted ABX:
S. pyogenes: PCN + clindamycin
Polymicrobial: Vancomycin + piperacillin/tazobactam
necrotizing fasciitis treatment duration
until patient has clinical improvement
Fever absent for 48-72 hours
why clindamycin?
inhibits streptococcal toxin production
inoculum effect –> maintains efficacy of ABX no matter amount of bacteria
Impetigo Characteristics/diagnosis
Highly contagious superficial skin infection
Cultures are recommended but not required
impetigo treatment few lesions
topical 5 days:
Mupirocin
impetigo treatment many lesions/outbreak
oral 7 days:
Dicloxacillin or cephalexin
Streptococcus only: DOC –> penicillin
Allergies/MRSA: doxycycline, clindamycin, TMP/SMX
animal bites
Cat bites : deep/ sharp puncture wounds
Dog/human bites: cellulitis signs and symptoms
Cultures: blood cultures are recommended in animal bites
animal bites pathogens
anaerobes since they are more common in the mouth
animal bites treatment
DOC: amoxicillin/clavulanate
Alterative: 2nd/3rd gen cephalosporin + anerobic coverage
B-lactam allergy: ciprofloxacin/levofloxacin + anerobic coverage or moxifloxacin
Vaccines: Tdap if due +/- rabies
animal bites treatment duration
Established infection: 7-14 days
Preemptive: 3-5 days
diabetic foot infection risk factors
neuropathy, angiopathy/ischemia, immunologic defects, poor wound healing
diabetic foot infection diagnosis
Presentation: local signs of infection +/- purulent discharge
More specific to DFI: discolored tissue/foul odor
Cultures:
Wound cultures: not recommended for mild infection
Bone cultures: typically following I&D
Blood cultures: may be considered
diabetic foot infection
Staph aureus, streptococci
Pseudomonas due to soaking
DFI - MRSA risk factors
in Indianapolis: add on MRSA coverage
Previous MRSA infection
DFI - Pseudomonas risk factors
Soaking feet in water
Hx pseudomonas
DFI - overall management
Surgery
Glycemic control
Antibiotics
DFI treatment mild
goal: cover MSSA + streptococci
1st line: for 1-2 weeks
dicloxacillin
cephalexin
clindamycin
Recent ABX: SWITCH TO amoxicillin/clavulanate
levofloxacin/moxifloxacin
MRSA risk factors: SWITCH TO sulfamethoxazole/trimethoprim
doxycycline
DFI treatment moderate
goal: cover MSSA, streptococci, enterobacterales, anaerobes
1st line: 2-3 weeks
moxifloxacin
amoxicillin/clavulanate
ciprofloxacin/levofloxacin
clindamycin or metronidazole
Pseudomonas risk factors: SWITCH TO
ciprofloxacin/levofloxacin + clindamycin or metronidazole
MRSA risk factors: ADD
doxycycline
linezolid
vancomycin
sulfamethoxazole/trimethoprim
DFI treatment severe
goal: cover MSSA, strep, enterobacterales, anaerobes, pseudomonas
1st line: 2-3 weeks
piperacillin/tazobactam
carbapenem
cefepime + clindamycin or metronidazole
MRSA: ADD vancomycin
linezolid
daptomycin
