January 11, 2011 — The Infectious Diseases Society of America (IDSA) has issued its first clinical practice guidelines for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections in children and adults.

The guidelines, released on January 5, will be published in the February 1 issue of Clinical Infectious Diseases.

The 13-member MRSA guidelines panel was convened by the IDSA Standards and Practice Guidelines Committee in 2007 to develop evidence-based, consensus guidelines for clinicians managing patients with MRSA infections.

The guidelines have been endorsed by the Pediatric Infectious Diseases Society, the American College of Emergency Physicians, and the American Academy of Pediatrics.

"These guidelines for MRSA have been eagerly anticipated," Paul Auwaerter, MD, MBA, who was not involved in their development, noted in an interview with Medscape Medical News.

"The guidelines synthesize current information in one comprehensive piece, even though they aren't all as evidenced-based as we'd like; a couple are way down in the C-III world," said Dr. Auwaerter, clinical director of the Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, Maryland.

"A lot of this is only expert opinion," he added, "but that's the best we have right now."

A "Living Document"

"MRSA is a major cause of both healthcare associated and community-associated infections," Catherine Liu, MD, lead author of the guidelines and assistant clinical professor in the Division of Infectious Diseases, University of California–San Francisco, told Medscape Medical News.

"It is the predominant cause of skin infections among patients presenting to the emergency room, and can also cause more serious, invasive infections that account for about 18,000 deaths in the United States per year," she noted.

"MRSA clearly has an enormous clinical and economic impact, and clinicians often struggle with the management of these infections," Dr. Liu added. The guidelines provide a "framework" to help clinicians determine how best to evaluate and treat patients with both uncomplicated and invasive infections caused by MRSA.

"It's designed to be a living document, meaning the recommendations will evolve as new information and antibiotics become available," Dr. Liu emphasized.

The guidelines address the management of a variety of clinical syndromes associated with MRSA disease, including skin and soft tissue infections (SSTIs), bacteremia and endocarditis, pneumonia, bone and joint infections, and central nervous system infections.

Some of the key recommendations, according to Dr. Liu, include the following:

• The management of all MRSA infections should include identification, elimination, and/or debridement of the primary source and other sites of infection when possible (eg, drainage of abscesses, removal of central venous catheters, debridement of osteomyelitis, etc).
• Education on personal hygiene and appropriate wound care is recommended for all patients with SSTIs. Patients should be instructed to keep draining wounds covered with clean, dry bandages; 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; and avoid reusing or sharing personal items that have contacted infected skin.
• For most simple abscesses or boils, incision and drainage alone is likely adequate, and antibiotic therapy is not needed. Antibiotic therapy is recommended for abscesses associated with the following conditions: severe or extensive disease or rapid progression in presence of associated cellulitis, signs and symptoms of systemic illness, associated comorbidities or immunosuppression (diabetes, HIV), extremes of age, abscess in area difficult to drain completely (eg, face, hand, genitalia), associated septic phlebitis, and lack of response to incision and drainage alone.
• In patients with MRSA bacteremia, follow-up blood cultures 2 to 4 days after initial positive cultures and as needed thereafter are recommended to document clearance of bacteremia.
• To optimize serum trough concentrations in adult patients, vancomycin should be dosed according to actual body weight (15 - 20 mg/kg/dose every 8 - 12 hours), not to exceed 2 g/dose. Trough monitoring is recommended to achieve target concentrations of 15 to 20 µg/mL in patients with serious MRSA infections and to ensure target concentrations in those who are morbidly obese, have renal dysfunction, or have fluctuating volumes of distribution. The efficacy and safety of targeting higher trough concentrations in children requires further study but should be considered in those with severe sepsis or persistent bacteremia.  In adults, monitoring of the peak vancomycin level is not recommended.
• When an alternative to vancomycin is being considered for use, in vitro susceptibility should be confirmed and documented in the medical record.
• For methicillin-sensitive S aureus infections, a beta-lactam antibiotic is the drug of choice in the absence of allergy.

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Each section of the guidelines begins with a specific clinical question, followed by numbered recommendations and a summary of the most relevant evidence in support of the recommendations.

"Certainly, where MRSA gets a lot of concern and treatment is in SSTIs, and here the guidelines give some nice and fairly clear-cut advice" on what to do in what specific situations, Dr. Auwaerter told Medscape Medical News.

"To me, as an infectious disease person, nothing is surprising in the guidelines," he added.

The guidelines also clearly highlight some of the knowledge gaps in certain areas. "Hopefully, this information could provide a map to address some additional key questions regarding MRSA that are out there," Dr. Auwaerter said.

Financial support for development of the guidelines was provided by IDSA. Dr. Liu has no relevant financial disclosures. Other study authors report financial relationships with the following companies: AdvanDx, Astellas, Clorox, Cubist, Forest, GeneOhn, Johnson and Johnson, Merck, Ortho-McNeil, Pfizer, Replidyne, Rib-X, Sage, Sanofi-Advantis, Sanofi Pasteur, Schering-Plough, Theravance, Targanta, Vicuron Pharmaceuticals, and Wyeth-Ayerst. Dr. Auwaerter has served as an advisor or consultant for LifeCell Corporation, Schering-Plough Corporation, and Wyeth Pharmaceuticals Inc and owns stock, stock options, or bonds in Johnson & Johnson Pharmaceutical Research & Development, LLC.

Clin Infect Dis. 2011;52:285-322. Abstract

Related Links
The full text of the IDSA guideline is available online.

Clinical Context

Clinical Implications

• The recommended treatment of MRSA SSTIs includes incision and drainage, oral antibiotics for 5 to 10 days, or intravenous antibiotics for 7 to 14 days, depending on the severity of infection.
• The recommended intravenous vancomycin dose for MRSA infection is 15 to 20 mg/kg/dose up to 2 g/dose every 8 to 12 hours for adults and 15 mg/kg/dose every 6 hours in children. Trough vancomycin levels before the fourth or fifth dose are the most accurate method to determine dosing in adult patients.

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