SKIN & SOFT-TISSUE INFECTIONS
MAIN PATHOGENS
1. Streptococcus pyogenes (“Strep”)
2. Staphylococcus aureus (“Staph”)- MRSA (“Methicillin-Resistant Staph Aureus”)
- MSSA (“Methicillin-Sensitive Staph Aureus”)
Clues for Distinguishing Staph from Strep
Suspect Staph
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Suspect Strep
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ANTIBIOTICS (click link for Common Doses)
Drugs for MSSA also kill Strep
1. Anti-Staphylococcal Penicillins (Methicillin class):- Dicloxacillin (oral)
- Oxacillin (parenteral)
- Cephalexin (oral)
- Cefazolin (parenteral) [3rd-Gen. Ceftriaxone too]
3. Amoxicillin + clavulanate (Augmentin®)
4. Clindamycin [see below under MRSA]
Drugs for MRSA do NOT kill Strep
1. Trimethoprim-Sulfamethoxazole (TMP-SMX) [Septra®, Bactrim®, et al.)
2. Doxycycline (the main tetracycline available)
3. Clindamycin (if not a serious infection)- Does kill Strep, doesn’t kill all MRSA
- If C&S “Sens” to Clinda but “Resist” to Erythromycin, may NOT kill MRSA
- Request an additional “D-Test” to know for sure
- Save for pt. discharged from hospital to complete course with p.o. Tx, when C&S not obtained
Treatment Strategies
MRSA not prevalent in community
1. Dicloxacillin OR Amoxicillin-Clavulante
2. Penicillin-Allergic: Cephalexin
3. Initial parenteral dose: Cefazolin OR Ceftriaxone- For rapid onset when hope to avoid admission
MRSA common in community
1. Make an educated diagnosis of Staph vs. Strep [see above]
2. If think Strep, treat as above (as if MRSA not an issue)
3. If think Staph & thus deal with MRSA:- Trimethoprim-Sulfamethoxazole (TMP-SMX)
- Doxycycline
- Clincamycin (if not a serious infection)
- Cefazolin OR Ceftriaxone
- plus TMP-SMA DS, 2 tabs
CAVEATS
1. NEVER give antibiotics for abscesses. Drain them.- May Rx antibiotic if abscess with large area of surrounding cellulitis
- Wrong Diagnosis, e.g. rash is not an infection
- Abscess (needs I & D)
- Foreign body
- Underlying osteomyelitis
- Possibly – wrong Antibiotic
3. Some special infections involve other microorganisms:
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> Debilitated pts, esp. infected decubiti > Infected burns > Gangrene, fasciitis > Rose-bush infection (fungal) > Sea-water infection > Dog & Cat Bites > Human bites |
See 2012 Guidlines from Infectious Disease Society of America.