Management of SSTI and DFI

Question 1

What are the two main classifications of SSTI?

Answer 1

Non-purulent and purulent.

Question 2

What organisms are typically associated with non-purulent SSTIs?

Answer 2

Streptococcus spp. (primarily Group A) and MSSA.

Question 3

What is the first-line treatment for mild non-purulent cellulitis?

Answer 3

Penicillin VK, cephalexin, or clindamycin for 5–7 days.

Question 4

When is MRSA coverage required in SSTIs?

Answer 4

Purulent infections or patients with risk factors like IV drug use, prior MRSA infection, or systemic signs.

Question 5

Which oral antibiotics cover MRSA in purulent SSTIs?

Answer 5

Clindamycin, doxycycline, TMP-SMX, linezolid.

Question 6

How is moderate purulent SSTI treated?

Answer 6

Incision and drainage plus oral MRSA-active antibiotics (e.g., TMP-SMX, doxycycline).

Question 7

How is severe purulent SSTI managed?

Answer 7

Incision and drainage plus IV MRSA-active antibiotics like vancomycin or linezolid.

Question 8

What are the signs of systemic infection requiring escalation of therapy?

Answer 8

Fever, hypotension, tachycardia, altered mental status.

Question 9

What factors make a DFI severe?

Answer 9

Systemic signs of infection, metabolic instability, deep tissue involvement, or extensive cellulitis.

Question 10

What organisms are most common in DFI?

Answer 10

Gram-positive cocci (Staph, Strep), Gram-negative rods (E. coli, Pseudomonas), and anaerobes.

Question 11

What is the empiric therapy for moderate DFI?

Answer 11

Amoxicillin-clavulanate or clindamycin + ciprofloxacin.

Question 12

What antibiotics are used for severe DFI requiring MRSA and Pseudomonas coverage?

Answer 12

Vancomycin + piperacillin-tazobactam or cefepime + metronidazole.

Question 13

What is the treatment duration for mild DFI?

Answer 13

Usually 1–2 weeks.

Question 14

What is the treatment duration for moderate to severe DFI?

Answer 14

2–4 weeks, depending on depth and osteomyelitis.

Question 15

When should imaging be considered in DFI?

Answer 15

If osteomyelitis is suspected (probe to bone test, chronic ulcer, or poor response to therapy).

Question 16

What is the preferred method for obtaining cultures in DFI?

Answer 16

Deep tissue or bone biopsy after wound debridement.

Question 17

What antibiotics are recommended for mild non-purulent SSTI (e.g., cellulitis)?

Answer 17

Penicillin VK, cephalexin, clindamycin.

Question 18

What IV antibiotics are used for moderate non-purulent SSTI?

Answer 18

Penicillin G, cefazolin, ceftriaxone.

Question 19

What is empiric treatment for severe non-purulent SSTI?

Answer 19

Vancomycin + piperacillin-tazobactam (or other broad Gram-negative and anaerobic coverage).

Question 20

What antibiotics are used for moderate purulent SSTI after I&D?

Answer 20

TMP-SMX or doxycycline.

Question 21

What antibiotics are used for severe purulent SSTI?

Answer 21

Vancomycin, daptomycin, linezolid, ceftaroline.

Question 22

What are oral options for mild diabetic foot infection (DFI)?

Answer 22

Amoxicillin-clavulanate, clindamycin + ciprofloxacin, TMP-SMX + doxycycline.

Question 23

What IV regimens are used for moderate to severe DFI?

Answer 23

Vancomycin + one of the following: cefepime, piperacillin-tazobactam, meropenem.

Question 24

What are oral step-down options for DFI when MRSA is not suspected?

Answer 24

Amoxicillin-clavulanate or fluoroquinolone + metronidazole.

Question 25

What antibiotics provide both Gram-negative and anaerobic coverage in DFI?

Answer 25

Piperacillin-tazobactam, ampicillin-sulbactam, ertapenem.

Question 26

What is the role of linezolid or daptomycin in DFI?

Answer 26

Used for MRSA coverage when vancomycin is contraindicated or in outpatient settings.

Question 27

What is the treatment for Streptococcus pyogenes in non-purulent SSTI?

Answer 27

Penicillin VK (oral) or Penicillin G (IV).

Question 28

What antibiotics cover MSSA in SSTI?

Answer 28

Cephalexin, dicloxacillin, cefazolin, or clindamycin.

Question 29

What antibiotics are preferred for MRSA SSTI?

Answer 29

TMP-SMX, doxycycline, clindamycin (oral); vancomycin, linezolid, daptomycin (IV).

Question 30

What is the treatment for MRSA in diabetic foot infections (DFI)?

Answer 30

Vancomycin, linezolid, or daptomycin.

Question 31

What is the treatment for Pseudomonas aeruginosa in DFI?

Answer 31

Piperacillin-tazobactam, cefepime, meropenem, or ciprofloxacin (if susceptible).

Question 32

What is the treatment for anaerobes in DFI?

Answer 32

Metronidazole or beta-lactam/beta-lactamase inhibitor combinations like amoxicillin-clavulanate or piperacillin-tazobactam.

Question 33

What is the treatment for ESBL-producing organisms in DFI?

Answer 33

Carbapenems like meropenem or ertapenem.

Question 34

What is the treatment for Enterococcus species in DFI?

Answer 34

Ampicillin (if susceptible), vancomycin, or linezolid.

Question 35

What are the key goals when evaluating skin and soft tissue infections (SSTIs)?

Answer 35

Classify infection type (purulent vs non-purulent), assess severity, identify likely pathogens, and choose empiric therapy.

Question 36

How are non-purulent and purulent SSTIs differentiated?

Answer 36

Non-purulent involves diffuse inflammation without pus; purulent presents with abscess or pus-filled lesion.

Question 37

What organisms are most likely in non-purulent SSTIs?

Answer 37

Primarily Streptococcus pyogenes and sometimes MSSA.

Question 38

What organisms are most likely in purulent SSTIs?

Answer 38

Usually Staphylococcus aureus, including MRSA.

Question 39

What are the treatment principles for SSTI based on severity?

Answer 39

Mild: oral agents; Moderate: oral or IV therapy; Severe: hospitalization, broad-spectrum IV antibiotics, surgery if needed.

Question 40

What are the classification criteria for diabetic foot infection (DFI)?

Answer 40

Mild: localized, no systemic signs; Moderate: deeper tissue, no systemic signs; Severe: systemic toxicity or metabolic instability.

Question 41

What are common pathogens in DFI?

Answer 41

Staph aureus (MSSA/MRSA), Streptococcus spp., Enterobacterales, anaerobes, and Pseudomonas in chronic/previously treated wounds.

Question 42

What empiric therapy is recommended for mild DFI?

Answer 42

Amoxicillin-clavulanate, cephalexin, clindamycin, or doxycycline.

Question 43

What empiric therapy is recommended for moderate to severe DFI?

Answer 43

Vancomycin plus Gram-negative/anaerobic coverage: piperacillin-tazobactam, cefepime + metronidazole, or meropenem.

Question 44

What duration of antibiotic therapy is appropriate for SSTI and DFI?

Answer 44

SSTI: 5–7 days if improving. DFI: 1–2 weeks (mild), 2–4 weeks (moderate-severe). Longer for osteomyelitis.