AAOS Now

Published 5/1/2012
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Paul Zemaitis

New Tools in the Battle Against MRSA

Methicillin-resistant Staphylococcus aureus (MRSA), a staph bacterium resistant to beta-lactam antibiotics, is most commonly associated with skin infections in the community and more severe, potentially life-threatening infections in the healthcare setting. Of the 25 percent to 30 percent of community residents who are colonized with S aureus, approximately 2 percent have MRSA.

According to the Centers for Disease Control and Prevention, among the estimated 478,000 hospitalizations with a diagnosis of S aureus infection in 2005, 278,000 were related to MRSA. During the same period, the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) estimated that the cost to treat hospitalized patients with MRSA infection was between $3.2 and $4.2 billion. ISPOR also reported that hospital length of stay was approximately 10 days longer in patients with MRSA infection, compared to patients with methicillin-susceptible S aureus infections.

Nasal surveillance, decolonization
Efforts to mitigate MRSA infections in the healthcare setting have been in place for some time and are having a positive impact. According to data presented by the National Healthcare Safety Network, MRSA infection rates—including bloodstream infections—have declined 50 percent from 1997 to 2007. Although these trends are promising, more can and should be done.

With growing attention being given to patient safety and quality in the healthcare setting, orthopaedists are uniquely positioned to play a central role in preventing these devastating infections. Helping implement protocols to prevent MRSA infections will not only save lives, but will also have far-reaching implications for containing health system costs. And while contact-precaution protocols and hand hygiene programs are now standard procedure for healthcare institutions, some facilities have added an additional preventive tool—universal nasal surveillance for MRSA.

In 2007, acute care Veterans Affairs (VA) hospitals nationwide implemented a “MRSA bundle” in an effort to decrease healthcare-associated MRSA infections. The bundle consisted of universal nasal surveillance for MRSA, contact precautions for patients colonized or infected with MRSA, hand hygiene, and a culture in which infection control became everyone’s responsibility.

A study of the VA’s initiative covering the period from October 2007 to June 2010 showed that the percentage of patients screened for MRSA at admission increased from 82 percent to 96 percent and that the percentage of patients screened for MRSA at transfer or discharge increased from 72 percent to 93 percent. Moreover, the rate of infections per 1,000 patient-days dropped from 1.64 to 0.62, a decrease of 62 percent (P < 0.001). In addition, rates of healthcare-associated MRSA infections per 1,000 patient-days in non–intensive-care units fell from 0.47 to 0.26, a decrease of 45 percent (P < 0.001). During the 2 years prior to the implementation of the ‘bundle,’ the rates of MRSA infection in VA-hospital intensive care units had not changed.

MRSA and SSIs
Data presented at the 2012 AAOS Scientific Exhibit, “The Current State of Bacterial Screening & Decolonization in Orthopaedic Surgery,” revealed that more than half of surgical site infections (SSIs) in orthopaedic surgery are caused by S aureus and that the incidence of MRSA SSIs is increasing. According to the same data, 85 percent of S aureus SSIs are caused by bacterial strains found in the patient’s nares.

Initiatives to screen and decolonize patients with MRSA prior to surgery have also shown promising results and have been shown to be cost-effective interventions. After screening individuals 2 to 4 weeks prior to surgery, a decolonization regimen of mupirocin ointment applied to both nares twice daily, and a daily chlorhexidine bath beginning 5 days prior to surgery resulted in a MRSA-eradication rate of roughly 83 percent.

A recently published study evaluated the use of screening and decolonization to prevent orthopaedic SSIs. The study included 1,440 patients in the intervention group, 2,284 patients in the concurrent control group, and 741 patients in a historical preintervention group. Of the individuals studied, 25 percent had a positive nasal culture and received preoperative mupirocin and chlorhexidine body wash. Of the individuals who screened positive and were treated (n = 321), none became infected with S aureus.

These data represent a promising trend in the effort to curb the burden MRSA has on patients and the healthcare system. Considering the prevalence of MRSA and the aging and infection-susceptible orthopaedic population, orthopaedists are in a position to have a considerable impact on preventing MRSA infections. Universal nasal surveillance and decolonization protocols provide them with additional tools in their fight against MRSA.

Paul Zemaitis is a regulatory/patient safety analyst in the biomedical research and regulation unit of the AAOS department of research & scientific affairs. He can be reached at zemaitis@aaos.org

References

  1. http://www.cdc.gov/mrsa/index.html
  2. www.infectioncontroltoday.com/news/2005/05/new-research-estimates-mrsa-infections-cost-u-s-h.aspx
  3. Jain R, Kralovic SM, Evans ME, et Al: Veterans Affairs initiative to prevent methicillin-resistant Staphylococcus aureus infections. N Engl J Med 2011;364(15):1419-1430.
  4. “The Current State of Bacterial Screening & Decolonization in Orthopaedic Surgery.” 2012 AAOS Patient Safety Committee Scientific Exhibit.
  5. Rao N, Cannella BA, Crossett LS, Yates AJ Jr, McGough RL 3rd, Hamilton CW:Preoperative screening/decolonization for Staphylococcus aureus to prevent orthopaedic surgical site infection: Prospective cohort study with 2-year follow-up. J Arthroplasty 2011;26(8):1501-1507.