Table 1. Recommendations for the Treatment of MRSA

Appendix 1. Conditions in which Antimicrobial Therapy is Recommended After Incision and Drainage of an Abscess Due to CA-MRSA

• Severe or extensive disease (eg, multiple sites) or rapid progression in presence of associated cellulitis
• Signs and symptoms of systemic illness
• Associated comorbidities or immunosuppression (diabetes mellitus, HIV/AIDS, neoplasm)
• Extremes of age
• Abscess in area difficult to drain completely (eg, face, hand, genitalia)
• Associated septic phlebitis
• Lack of response to incision and drainage alone

Management of Recurrent MRSA Skin and Soft Tissue Infections

• Preventive educational messages on personal hygiene and appropriate wound care are recommended for all patients with SSTI. Instructions should be provided to:
  • Keep draining wounds covered with clean, dry bandages (A-III).
  • Maintain good personal hygiene with regular bathing and cleaning of hands with soap and water or an alcohol-based hand gel, particularly after touching infected skin or item that has directly contacted a draining wound (A-III).
  • Avoid reusing or sharing personal items (eg, razors, linens and towels) that have contacted infected skin (A-III).
• Environmental hygiene measures should be considered in patients with recurrent SSTI in the household/community setting:
  • Focus cleaning efforts on high-touch surfaces that may contact bare skin or uncovered infections (C-III).
  • Commercially available cleaners or detergents appropriate for the surface being cleaned should be used according to label instructions for routine cleaning of surfaces (C-III).
• Decolonization may be considered in selected cases if:
  • A patient develops a recurrent SSTI despite optimizing wound care and hygiene measures (C-III).
  • Ongoing transmission is occurring among household members or other close contacts despite optimizing wound care and hygiene measures (C-III).
• Decolonization strategies should be offered in conjunction with ongoing reinforcement of hygiene measures and may include:
  • Nasal decolonization with mupirocin twice daily for 5-10 days (C-III).
  • Nasal decolonization with mupirocin twice daily for 5-10 days and topical body decolonization regimens with a skin antiseptic solution (eg, chlorhexidine) for 5-14 days or dilute bleach baths (1 teaspoon per gallon of water or 1/4 cup per 1/4 bathtub [or 13 gallons of water] given for 15 minutes twice weekly for ~3 months can be considered) (C-III).
• Oral antimicrobial therapy is recommended for the treatment of active infection only and is not routinely recommended for decolonization (A-III). An oral agent in combination with rifampin, if susceptible, may be considered for decolonization if infections recur despite above measures (C-III).
• In cases where household or interpersonal transmission is suspected:
  • Personal and environmental hygiene measures in the patient and contacts are recommended (A-III).
  • Contacts should be evaluated for evidence of S. aureus infection:
  • Symptomatic contacts should be evaluated and treated (A-III); nasal and topical body decolonization strategies may be considered following treatment of active infection (C-III).
  • Nasal and topical body decolonization of asymptomatic household contacts may be considered (C-III).
• The role of cultures in the management of patients with recurrent SSTI is limited:
  • Screening cultures prior to decolonization are NOT routinely recommended if at least one of the prior infections was documented as MRSA (B-III).
  • Surveillance cultures following a decolonization regimen are NOT routinely recommended in the absence of an active infection (B-III).

MRSA Infections in Neonates

Neonatal pustulosis

• For mild cases with localized disease, topical treatment with mupirocin may be adequate in full-term neonates and young infants (A-III).
• For localized disease in a premature or very low birthweight infant or more extensive disease involving multiple sites in full-term infants, IV vancomycin or clindamycin is recommended at least initially until bacteremia is excluded (A-II).
  

Neonatal MRSA sepsis

• IV vancomycin is recommended, dosing as outlined in the Red Book (A-II).
• Clindamycin and linezolid are alternatives for non-endovascular infections (B-II).

Vancomycin Monitoring

• Trough vancomycin concentrations are the most accurate and practical method to guide vancomycin dosing (B-II). Serum trough concentrations should be obtained at steady state conditions, prior to the fourth or fifth dose. Monitoring of peak vancomycin concentrations is not recommended (B-II).
• For serious infections such as bacteremia, infective endocarditis, osteomyelitis, meningitis, pneumonia, and severe SSTI (eg, necrotizing fasciitis) due to MRSA, vancomycin trough concentrations of
  15-20 mcg/mL are recommended (B-II).
• For most patients with SSTI who have normal renal function and are not obese, traditional doses of 1 gram every 12 hours are adequate and trough monitoring is not required (B-II).
• Trough vancomycin monitoring is recommended for serious infections and patients who are morbidly obese, have renal dysfunction including those on dialysis, or have fluctuating volumes of distribution (A-II).
• Continuous infusion vancomycin regimens are not recommended (A-II).
• The efficacy and safety of targeting trough concentrations of
  15-20 mcg/mL in children requires further study but should be considered in those with serious infections such as bacteremia, infective endocarditis, osteomyelitis, meningitis, pneumonia, and severe SSTI (ie, necrotizing fasciitis) (B-III).

Vancomycin Susceptibility Testing

• There is considerable variability in MIC results depending on the method used. One challenge is that acceptable variability for MIC methods is /- one doubling dilution making it difficult to distinguish between a MIC of 1 vs. 2 mcg/mL.
• Etest, MicroScan, and BD-Phoenix report higher MIC values than reference broth microdilution, overcalling susceptible strains as intermediate in some cases while the Sensititre and Vitek 2 systems tend to undercall resistance.
• As current susceptibility testing methods are unable to reliably distinguish between MICs of 1 mcg/mL from 2 mcg/mL and vice versa, the patient’s clinical and microbiologic response should be evaluated along with MIC results when making decisions regarding therapy.
• For isolates with a vancomycin MIC ≤ 2, eg, “susceptible” according to CLSI breakpoints, the patient’s clinical response should determine the continued use of vancomycin, independent of the MIC (A-III).
  • If the patient has had a clinical and microbiologic response to vancomycin, then it may be continued with close follow-up
  • If the patient has not had a clinical or microbiologic response to vancomycin despite adequate debridement and removal of other foci of infection, an alternative to vancomycin is recommended regardless of MIC.
• For isolates with a vancomycin MIC > 2 mcg/mL, eg, vancomycin-intermediate S. aureus (VISA) or vancomycin-resistant S. aureus (VRSA), an alternative to vancomycin should be used (A-III).

Persistent MRSA Bacteremia and Vancomycin Treatment Failures in Adults

• A search for and removal of other foci of infection, drainage or surgical debridement is recommended (A-III).
• High-dose daptomycin, if the isolate is susceptible, in combination with other agents should be considered (B-III).
  • Please see antibiotic recommendations in full text guidelines for details at
    http://www.idsociety.org/content.aspx?id=4432#mrsa
• If reduced susceptibility to vancomycin and daptomycin are present, options may include: quinupristin-dalfopristin 7.5 mg/kg/dose IV every 8 hours, trimethoprim/sulfamethoxazole 5 mg/kg/dose IV twice daily, linezolid 600 mg PO/IV twice daily, or telavancin 10 mg/kg/dose
  IV once daily (C-III).

These options may be given as a single agent or in combination with other antibiotics.