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Methicillin-Resistant Staph Aureus Infections

King County Public Health Guidelines for MRSA (Print PDF 116 kb)
Author: Tim Dellit, MD

Empiric Oral Antimicrobial Agents for Treatment of Outpatients with Suspected MRSA

Selection of empiric therapy should be guided by local S. aureus susceptibility and
modified based on results of culture and susceptibility testing. The duration of
therapy for most SSTI is 7-10 days, but may vary depending on severity of infection
and clinical response. NOTE: Before treating, clinicians should consult complete
drug prescribing information in the manufacturer’s package insert or the PDR.



Adult Dose
Pediatric Dose


1 tablet (160 mg TMP/800 mg SMX) PO bid

Base dose on TMP:
8-12 mg TMP
(& 40-60 mg SMX)
per kg/day
in 2 doses; not to exceed adult dose

minocycline or doxycycline** 100 mg PO bid Not recommended
for pediatric use –
suggest consultation with infectious
disease specialist before use
clindamycin 300-450 mg PO qid 10-20 mg/kg/day in
3-4 doses; not to exceed adult dose

**Tetracycline - minocycline and doxycycline have greater antistaphylococcal activity than other oral tetracyclines and have been effective clinically. Minocycline may cause vestibular disturbances with vertigo, nausea and vomiting.

NOTE: If Group A streptococcal infection is suspected, oral therapy
should include an agent active against this organism (ß-lactam, macrolide, clindamycin). Tetracyclines and trimethoprim-sulfamethoxazole, although
active against many MRSA, are not recommended treatments for suspected
GAS infections.

NOTE: Outpatient use of quinolones or macrolides. Fluoroquinolones (e.g.,ciprofloxicin, levofloxacin, moxifloxacin, gatifloxacin ) and macrolides
(e.g., erythromycin, clarithromycin, azithromycin) are NOT recommended for treatment of MRSA because of high resistance rates. If fluoroquinolones are being considered, consult with infectious disease specialist before use.

NOTE: Outpatient use of Linezolid in SSTI. Linezolid is costly and has
great potential for inappropriate use, inducing antimicrobial resistance, and toxicity. Although it is 100% bioavailable and effective in SSTI, it is not recommended for empiric treatment or routine use because of these
concerns. It is strongly recommended that linezolid only be used after consultation with an infectious disease specialist to determine if alternative antimicrobials would be more appropriate.

*Isolates resistant to erythromycin and sensitive to clindamycin
should be evaluated for inducible clindamycin resistance (MLSB phenotype) using the “D test.”
Consult with your reference laboratory
to determine if “D testing” is routine or must be specifically requested.
If inducible resistance is present, an alternative agent to clindamycin
should be considered.

MRSA Susceptibilities at HMC

Click on image to enlarge

Updated 1/2008




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