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Multidrug-resistant organisms, MRSA, CRE, KPC


Multi-drug resistant organisms

Multidrug-resistant organisms (MDROs), such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) have important infection control implications in all healthcare settings. Because the severity and extent of disease caused by MDROs varies by the patient population and type of care setting (e.g., long-term care facility, intensive care units), the approaches to prevention and control need to be tailored to the specific needs of each population and individual institution. The prevention and control of MDROs is a national priority, one that requires that all healthcare facilities and agencies assume responsibility.

Control of antimicrobial resistance

A major factor in the emergence of antibiotic resistant organisms is overuse of antibiotics in any setting, the hospital or the community. There are numerous national efforts to reduce the use of antibiotics or promote appropriate use in the community and all healthcare delivery systems.

Antimicrobial resistance took a long time to develop - considering that penicillin resistance began soon after its discovery in the 1940s. So it will not be fixed overnight, solutions will not be simple, and there is no single solution.

There are number of national initiatives to control antimicrobial resistance by public, private and professional groups. CDC has outlined a campaign - a 12-step program to prevent antimicrobial resistance in healthcare settings.  Key steps include vaccination to prevent infections (e.g., pneumococcal vaccination), removal of devices as soon as feasible, and effective diagnosis and appropriate use of antimicrobial agents. There are other resources to encourage proper use of antibiotics, such as the Michigan Antibiotic Resistance Reduction Coalition as well as the Infectious Disease Society of America (IDSA) antibiotic stewardship guidelines.

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CDC recommendations to prevent MDRO transmission

The CDC's guideline on "Management of MDROs in Healthcare Settings, 2006" includes a road map for developing a comprehensive, multifaceted approach to stop the transmission of MDROs including elements such as antimicrobial use, finding resources for a program, and surveillance. The recommendations challenge hospitals to implement a program that documents reduction and to accomplish that, recommends a two-tiered approach.

Methicillin-resistant Staphylococcus aureus (MRSA)

MRSA is the most common MDRO causing healthcare-associated infections (HAIs). MRSA can cause a range of infections from mild skin infections to more severe infections of the bloodstream, lungs and surgical sites. In the October 2007 issue of the Journal of the American Medical Association, the CDC estimated 94,000 serious, invasive drug-resistant Staph aureus infections (MRSA) occurred in the U.S. in 2005 with an estimate of MRSA deaths greater than 18,000. This study established the first national baseline by which to assess future trends in invasive MRSA infections.  

In testimony to Congress in November 2007, Julie Gerberding, Director of CDC, noted that MRSA was not a new problem, but the attention and public anxiety are new. MRSA mostly commonly causes skin infections, such as boils and abscesses; however, sometimes can spread to cause life-threatening blood infections.

In healthcare settings, MRSA occurs most frequently among patients who undergo invasive medical procedures or who have weakened immune systems and are being treated in hospitals and healthcare facilities such as nursing homes and dialysis centers.

Although much of the media attention has focused on this single organism, MRSA, it is only one of many organisms causing both HAIs and community infections.  However, healthcare providers are encouraged that the media attention on MRSA will highlight the seriousness of HAIs and assist with efforts to secure additional resources for tracking, prevention and elimination of all types of HAIs.

For more information on HAI and MRSA, see Resources and tools.


Carbapenem-resistant Enterobacteriaceae (CRE)
including Klebsiella pneumoniae carbapenemase(KPC)

The emergence and dissemination of carbapenem resistant Enterobacteriaceae (CRE) throughout many parts of the United States represent a serious threat to public health. These organisms are associated with high mortality rates, up to 40-50 percent, and have the potential to spread widely. CRE appear to have been uncommon in the United States before 1992, however, most common are Klebsiella pneumoniae carbapenemase (KPC) that have disseminated widely throughout the United States since being first reported in 2001.

Due to the movement of patients throughout the healthcare system, if CRE are a problem in one facility, then typically they are a problem in other facilities in the region as well. CDC's surveillance definition of CRE is resistance to all of the following third-generation cephalosporins that were tested: ceftriaxone, cefotaxime, and ceftazidime, all three being recommended as part of the primary or secondary susceptibility panels for Enterbacteriaceae. To help protect patients and prevent transmission, in June 2012, CDC released a CRE toolkit which expands on 2009 CDC recommendations and continues to be updated as new information becomes available.

Increasing number of unusual forms of CRE in the US since July 2012

New Detect and Protect strategy

In March 2013, CDC launched a new initiative "Detect and Protect" to combat the increasing spread of real and deadly infections with CRE. Detection involves using the correct tests to identify CRE in the clinical laboratory, alerting clinical staff immediately when CRE is detected, and notifying receiving facilities when patients with CRE are transferred. Protection includes applying standard and contact precautions such as meticulous attention to environmental and hand hygiene for all CRE patient care. CDC has created a number of tools to help state officials, health care leaders, clinicians, and patients take steps to stop the spread of CRE.


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