Erdman SSTI

Question 1

Common Cellulitis Bacteriology

Answer 1

Staphylococcus aureus
Streptococcus pyogenes (group A streptococcus)

Question 2

Cellulitis Empiric Therapy General Considerations

Answer 2

Should be directed against both Group A strep & S. aureus since clinical features are indistinguishable

Question 3

Mild Cellulitis Infection Empiric Therapy Adult

Answer 3

Dicloxacillin 500 mg PO q6h
OR
Cephalexin 500 mg PO q6h

Question 4

Mild Cellulitis Infection w/ Suspected MRSA Empiric Therapy Adult

Answer 4

TMP-SMX 2 DS PO q12h
OR 
Clindamycin 300-450 mg PO q6h
OR 
Linezolid 600 mg PO q12h

Question 5

Mild Cellulitis Infection Empiric Therapy Pediatric

Answer 5

Dicloxacillin 25-50 mg/kg/day PO in 4 divided doses
OR
Cephalexin 25-50 mg/kg/day PO in 4 divided doses

Question 6

Mild Cellulitis Infection w/ Suspected MRSA Empiric Therapy Pediatric

Answer 6

TMP-SMX 8-12 mg/kg/day TMP PO in 2 divided doses
OR
Clindamycin 8-20 mg/kg/day in 3-4 divided doses
OR
Linezolid 10 mg/kg PO q12h

Question 7

Moderate-Severe Cellulitis Infection Empiric Therapy Adult

Answer 7

Nafcillin 1-2 grams IV q4-6h
OR
Cefazolin 1-2 grams IV q8h

Question 8

Moderate-Severe Cellulitis Infection w/ Suspected MRSA Empiric Therapy Adult

Answer 8

Vancomycin 15 mg/kg IV q12h
OR
Linezolid 600 mg IV or PO q12h

Question 9

Moderate-Severe Cellulitis Infection Empiric Therapy Pediatric

Answer 9

Nafcillin 150-200 mg/kg/day IV in 4-6 divided doses (max 12 grams/day)
OR
Cefazolin 50-100 mg/kg/day IV in 3 divided doses

Question 10

Moderate-Severe Cellulitis Infection w/ Suspected MRSA Empiric Therapy Pediatric

Answer 10

Vancomycin 10-15 mg/kg IV q6-8h
OR
Linezolid 10 mg/mg IV or PO q12h

Question 11

Empiric Cellulitis Therapy Severe Penicillin Allergy

Answer 11

Clindamcyin, vancomycin, linezolid

Question 12

Cellulitis Duration of Therapy

Answer 12

Minimum of 5 days

Question 13

Common Impetigo Bacteriology

Answer 13

Staphylococcus aureus
Streptococcus pyogenes (group A streptococcus)

Question 14

Mild Impetigo Treatment

Answer 14

Mupirocin 2% BID x 5 days

Retapamulin 1% BID x 5 days

Question 15

Impetigo Treatment For Adults w/ Numerous Lesions or During Outbreak

Answer 15

Dicloxacillin 500 mg PO q6h
Cephalexin 500 mg PO q6h
Erythromycin 500 mg PO q6h
Clindamycin 300 mg PO q8h
Amoxicillin/clavulanate 875 mg PO 12h

Question 16

Impetigo Treatment For Pediatrics w/ Numerous Lesions or During Outbreak

Answer 16

Cephalexin 25-50 mg/kg/day PO in 3-4 divided doses
Erythromycin 40 mg/kg/day PO in 3-4 divided doses
Clindamycin 20 mg/kg/day PO in 3 divided doses
Amoxicillin/clavulanate 25 mg/kg/day amoxicillin PO in 2 divided doses

Question 17

Impetigo Systemic Treatment Duration of Therapy

Answer 17

7 days

Question 18

Necrotizing Fasciitis Monomicrobial Bacteriology

Answer 18

Streptococcus progenies (group A strep)

Question 19

Necrotizing Fasciitis Polymicrobial Bacteriology

Answer 19

Mixed infection involving organisms from GI or GU tract (gram-negative aerobes and anaerobes)

Question 20

Necrotizing Fasciitis Empiric Therapy

Answer 20

Surgery +

Vancomycin + piperacillin/ tazobactam, meropenem, ceftriaxone & metronidazole OR FQ/metronidazole

Question 21

Necrotizing Fasciitis Directed Therapy for Streptococcus pyogenes, Clostridium spp

Answer 21

Penicillin + clindamycin (suppresses toxin production)

Question 22

Necrotizing Fasciitis Directed Therapy for Staphylococcus aureus

Answer 22

MSSA - nafcillin or cefazolin

MRSA - vancomycin

Question 23

Necrotizing Fasciitis Directed Therapy for Aeromonas hydrophila

Answer 23

Doxycycline + ciprofloxacin

Question 24

Necrotizing Fasciitis Directed Therapy for Vibrio vulnificus

Answer 24

Doxycycline + ceftriaxone

Question 25

Mild Diabetic Foot Infection

Answer 25

Cellulitis extending < 2 cm around ulcer
Infection limited to skin/superficial tissue
Patient without systemic s/sx

Question 26

Moderate Diabetic Foot Infection

Answer 26

Cellulitis extending > 2 cm around ulcer OR
Involving structure deeper than skin/superficial tissue
Patient without systemic s/sx

Question 27

Severe Diabetic Foot Infection

Answer 27

Local infection with signs of SIRS manifested by ≥ 2 of the following: temp >38°C or <36°C, heart rate >90 beats/min, respiratory rate >20 breaths/min, WBC >12,000 or <4,000 cells/μL or >10% immature (band)

Question 28

ESR or C-Reactive Protein Monitoring

Answer 28

Only for pts w/ diabetic foot infection and suspected osteomyelitis

Question 29

Mild Diabetic Foot Infection Likely Causative Organism

Answer 29

β-hemolytic Streptococcus and/or Staphylococcus aureus

Question 30

Mild Diabetic Foot Infection Empiric Therapy

Answer 30

PO Cephalexin or
PO Dicloxacillin or
PO Amoxicillin/clavulanate

Question 31

Mild Diabetic Foot Infection w/ Suspected MRSA Empiric Therapy

Answer 31

PO Clindamycin or PO TMP-SMX

Question 32

Moderate Diabetic Foot Infection Likely Causative Organism

Answer 32

β-hemolytic Streptococcus and/or Staphylococcus aureus

• Consider Enterobacteriaceae if on abx in past 30 days
• *Consider anaerobes if nectroic wound has not been debrided

Question 33

Moderate Diabetic Foot Infection Empiric Therapy

Answer 33

IV Cefazolin

Question 34

Moderate Diabetic Foot Infection w/ Suspected MRSA Empiric Therapy

Answer 34

IV Vancomycin

Question 35

Moderate Diabetic Foot Infection w/ Suspected Enterobacteriaceae Empiric Therapy

Answer 35

IV Ceftriaxone

Question 36

Moderate Diabetic Foot Infection w/ Suspected Anaerobes Empiric Therapy

Answer 36

IV Cefazolin + PO metronidazole

Question 37

Severe Diabetic Foot Infection Like Causative Organism

Answer 37

β-hemolytic Streptococcus, Staphylococcus aureus (MSSA and MRSA), Enterobacteriaceae, P. aeruginosa, anaerobes

Question 38

Severe Diabetic Foot Infection Empiric Therapy

Answer 38

IV Vancomycin +
piperacillin/tazobactam; meropenem OR ceftazidime/cefepime with PO metronidazole; OR levofloxacin/ciprofloxacin with PO metronidazole

Question 39

Diabetic Foot Infection Empiric Therapy for MRSA Criteria

Answer 39

Prior history of MRSA infection/colonization
When the local prevalence of MRSA is high
Patients with severe infection

Question 40

Diabetic Foot Infection Empiric Therapy for P. aeruginosa Criteria

Answer 40

Patients with frequent exposure of the foot to water
Patients who failed therapy with nonpseudomonal agents
Patients with severe infection.