CDC answers questions about MDROs

Definitions, precautions, and risks identified

Some key questions related to multidrug resistant organisms (MDROs) that are most likely to be seen in non-hospital healthcare settings are answered by the Centers for Disease Control and Prevention in Atlanta. This information, along with other guidance provided by the CDC, can be used to develop or enhance staff education material.

A few of the questions and answers are:

What are "non-hospital health care settings"?

They refer to residential settings (e.g., long-term care and skilled nursing homes), home care, hemodialysis centers, and physicians' offices.

What are multidrug-resistant organisms? They are bacteria and other microorganisms that have developed resistance to antimicrobial drugs. Common examples of these organisms include:

• MRSA - methicillin/oxacillin-resistant Staphylococcus aureus

• VRE - vancomycin-resistant enterococci

• ESBLs - extended-spectrum beta-lactamases (which are resistant to cephalosporins and monobactams)

• PRSP - penicillin-resistant Streptococcus pneumoniae

Which multidrug-resistant organisms are most commonly seen in non-hospital settings?

MRSA and VRE are the most commonly encountered multidrug-resistant organisms in patients residing in non-hospital health care facilities, such as nursing homes and other long-term care facilities. PRSP are more common in patients seeking care in outpatient settings such as physicians' offices and clinics, especially in pediatric settings.

What is the difference between colonization and infection?

Colonization means that the organism is present in or on the body but is not causing illness. Infection means that the organism is present and is causing illness.

What conditions increase the risk of acquiring these organisms?

There are several risk factors for both colonization and infection:

• severity of illness;

• previous exposure to antimicrobial agents;

• underlying diseases or conditions, particularly:

- chronic renal disease

- insulin-dependent diabetes mellitus

- peripheral vascular disease

- dermatitis or skin lesions;

• invasive procedures, such as:

- dialysis

- presence of invasive devices

- urinary catheterization;

• repeated contact with the health care system;

• previous colonization by a multidrug-resistant organism;

• advanced age.

What can be done to prevent or control transmission of these pathogens in my facility?

CDC's recommendations for preventing transmission of MRSA/VRE in hospitals consist of standard precautions, which should be used for all patient care. In addition, CDC recommends contact precautions when the facility (based on national or local regulations) deems the multidrug-resistant microorganism to be of special clinical and epidemiologic significance.

The components of contact precautions may be adapted for use in non-hospital health care facilities, especially if the patient has draining wounds or difficulty controlling body fluids.

The following are recommended for prevention of VRE / MRSA in hospitals and may be adapted for use in non-hospital health care facilities:

• Obtain stool cultures or rectal swab cultures of roommates of patients newly found to be infected or colonized with VRE, and nasal swabs for MRSA.

• Adopt a policy for deciding when patients can be removed from isolation, e.g., VRE-negative results on at least three consecutive occasions, one or more weeks apart.

• Consult health departments regarding discharge requirements for patients with MRSA or VRE.

What precautions should family caregivers take for infected persons in their homes?

Outside of health care settings, there is little risk of transmitting organisms to persons at risk of disease from MRSA/VRE; therefore, healthy people are at low risk of getting infected. In the home, the following precautions should be followed:

• Caregivers should wash their hands with soap and water after physical contact with the infected or colonized person and before leaving the home.

• Towels used for drying hands after contact should be used only once.

• Disposable gloves should be worn if contact with body fluids is expected, and hands should be washed after removing the gloves.

• Linens should be changed and washed if they are soiled and on a routine basis.

• The patient's environment should be cleaned routinely and when soiled with body fluids.

• Notify doctors and other healthcare personnel who provide care for the patient that the patient is colonized/infected with a multidrug-resistant organism.


1. Centers for Disease Control and Prevention. Multidrug-Resistant Organisms in Non-Hospital Healthcare Settings Website: 2009.


For more information about multi-drug resistant organisms in community settings, go to:

For more information about standard precautions, go to: