SSTI and Osteomyelitis

What is the classic presentation of non-bullous impetigo?

Honey-colored crusted lesions on the face, superficial infection.

First-line treatment for localized impetigo?

Topical mupirocin BID x 5 days.

When is oral therapy preferred in impetigo?

Numerous lesions or outbreaks affecting multiple people.

Most common organisms in impetigo?

GAS and MSSA.

Typical presentation of bullous impetigo?

Flaccid bullae caused by S. aureus toxin.

Presentation of ecthyma?

Deep ulcerative lesions into dermis with thick crust.

Risk factors for impetigo outbreaks?

Warm climates, minor skin trauma, crowded living, children.

Most important step in treating purulent abscesses?

Incision and drainage (I&D).

Common organism in furuncles/carbuncles?

Staphylococcus aureus (MSSA/MRSA).

Indications for antibiotics after I&D?

Systemic symptoms, multiple abscesses, immunocompromised, failure of drainage.

Oral MRSA agents for purulent SSTI?

TMP-SMX, doxycycline, clindamycin.

Presentation of non-purulent cellulitis?

Diffuse erythema, warmth, swelling, no pus.

Most common organism in non-purulent cellulitis?

Streptococcus pyogenes.

First-line oral therapy for mild non-purulent cellulitis?

Penicillin VK or cephalexin.

First-line IV therapy for moderate/severe non-purulent cellulitis?

Cefazolin or ceftriaxone.

When to cover MRSA in cellulitis?

Penetrating trauma, IVDU, MRSA history, systemic signs.

Duration of mild cellulitis treatment per IDSA?

5 days, extend if not improving.

Risk factors for cellulitis recurrence?

Tinea pedis, obesity, lymphedema, chronic edema.

Presentation of diabetic foot infection?

Ulcers with drainage, surrounding cellulitis, possible foul odor.

Mild DFI common pathogens?

MSSA and Streptococci.

Moderate-severe DFI common pathogens?

Polymicrobial: gram-positives, gram-negatives, anaerobes.

When is Pseudomonas likely in DFI?

Soaking feet, warm climates, recurrent infection, high local prevalence.

Empiric therapy for mild DFI?

Cephalexin or amoxicillin-clavulanate.

Empiric therapy for moderate-severe DFI?

Ampicillin-sulbactam, ertapenem, or pip-tazo ± vancomycin.

Duration of soft-tissue DFI without osteomyelitis?

1-2 weeks.

Key clinical sign of necrotizing fasciitis?

Pain out of proportion.

What is the first and most important treatment in necrotizing fasciitis?

Immediate surgical debridement.

Empiric antibiotics for necrotizing fasciitis?

Vancomycin + pip-tazo or carbapenem.

Why add clindamycin in GAS necrotizing fasciitis?

Toxin suppression and cytokine inhibition.

Key organisms in type I necrotizing fasciitis?

Polymicrobial: anaerobes + gram negatives + streptococci.

Key organism in type II necrotizing fasciitis?

Group A Streptococcus (GAS).

Organism associated with saltwater exposure wounds?

Vibrio vulnificus.

Best treatment for Vibrio infection?

Doxycycline + ceftriaxone.

Most common organism in cat bites?

Pasteurella multocida.

Most common organism in human bites?

Eikenella corrodens.

First-line therapy for infected dog/cat bite?

Amoxicillin-clavulanate.

Duration of treatment for infected animal bite?

10-14 days.

Who should receive prophylaxis after animal bites?

Immunocompromised, deep wounds, hand wounds, severe edema, asplenia.

What extra steps are required for bite wounds?

Tetanus update ± rabies prophylaxis if indicated.

Preferred imaging for osteomyelitis?

MRI.

Gold standard for osteomyelitis diagnosis?

Bone biopsy.

Most common organism in adult osteomyelitis?

Staphylococcus aureus.

Empiric therapy for osteomyelitis with MRSA risk?

Vancomycin + cefepime or pip-tazo.

Duration of osteomyelitis treatment if bone is NOT removed?

6 weeks.

Duration of osteomyelitis treatment if infected bone IS removed?

2-5 days post-op.

Monitoring parameter for daptomycin therapy?

CK weekly.

Major toxicity risk with clindamycin?

C. difficile diarrhea.

Major toxicity with linezolid?

Thrombocytopenia and serotonin syndrome.

Safety monitoring common to most SSTI treatments?

Renal function, CBC, liver function depending on drug.

Effectiveness monitoring common across all SSTIs?

Reduced redness/swelling/pain within 48-72 hours.