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Drug-Resistant Organisms

What are drug-resistant organisms?

Drug-Resistant Organisms (DROs) are bacteria, viruses, and other organisms that have developed a resistance to certain drugs. In other words, a particular drug is no longer able to kill or control a specific bacteria or organism. Other terms used to describe this situation include multidrug resistant (MDR), antibiotic resistance, antibacterial resistance, and antimicrobial resistance.

Examples of drug-resistant organisms include:

  • MRSA - Methicillin/oxacillin-resistant Staphylococcus aureus.
  • CA-MRSA - Community-acquired methicillin-resistant Staphylococcus aureus.
  • VRE - Vanomycin-resistant enterococci.
  • ESBLs - Extended-spectrum beta lactamases (resistant to cephalosporins and monobactams).
  • PRSP - Penicillin-resistant Streptococcus pneumoniae.
  • GISA - Glycopeptide-intermediate Staphylococcus aureus.
  • VISA - Vancomycin-intermediate Staphylococcus aureus.
  • VSRA - Vancomycin-resistant Staphylococcus aureus.
  • MDR-TB - Multidrug-resistant tuberculosis.
  • MDRSP - Multidrug resistant Staphylococcus pneumoniae.

Are DROs a new problem?

No. Penicillin resistance to Staphylococcus aureus was first noted in the 1940s. Wide spread use of antibiotics plus the natural evolution of bacteria over time has led to a number of drug-resistant strains emerging.

Will I get sick if I come in contact with a DRO?

Not necessarily. If you are sick, you are considered to be "infected". Infection means that the organism or bacteria is present in or on your body and that it is causing an illness or other medical condition.

In some cases, it is possible for the organism to be present but not causing an illness. Such cases are called 'colonization'. For example, Staphylococcus aureus is commonly found in various areas of the body including the nose. Colonization rarely becomes an infection unless the bacteria are spread to a different and susceptible part of the body.

What are some risk factors for being infected or colonized by a DRO?

In general, people who are healthy are at low risk of becoming colonized or infected. Casual contact such as hugging and touching with a person who has a DRO is usually considered okay (Centers for Disease Control and Prevention, 2010). If in a hospital, however, it is important to wash your hands before you leave the patient's room (or when visiting with an infected or colonized person in order to prevent the organism from spreading). Follow the healthcare provider's instructions or the visitor policy for that facility.

The risk of colonization and infection are increased if you have:

  • An existing severe illness.
  • An underlying disease or condition is present such as:
    • Chronic renal disease.
    • Insulin dependent vascular disease.
    • Dermatitis or skin lesions.
  • Previous exposure to antimicrobial agents.
  • Undergone an invasive procedures such as dialysis and catheterization.
  • Repeated contact with the healthcare system.
  • A long stay in a hospital.
  • Previous colonization by a DRO.
  • Are on immune-suppressing medication.
  • If you are elderly, a pregnant woman, or a young child.

How are DROs spread?

DROs spread the way other bacteria and organisms spread. Contact (touching) devices or surfaces contaminated with body fluids from an infected person or direct hand/skin contact are the most common routes of exposure.

According to the Centre for Disease Control and Prevention (CDC) certain drug resistant organisms can be found in the general community. Infection risk is higher in places where there is direct contact from an infected wound, or by sharing personal items (e.g., towels or razors) that have touched infected skin.  Risk is also higher where activities or situations involve crowding, skin-to-skin contact, and shared equipment or supplies.  Examples include athletic events or gyms, daycare or school, military personnel in barracks, and people who have recently received inpatient medical care.

What are ways to control the spread of DROs?

The Public Health Agency of Canada advises that you discuss with your healthcare provider what is the appropriate medicine for your illness and avoid overusing or misusing antimicrobial medication.  Take the all of the medication that is prescribed to you, even if you are feeling better. Never take medication that was not prescribed to you.

  • Hand hygiene is one of the most effective ways to control the spread of bacteria, organisms, and other infections. Please see the OSH Answers document, Hand Washing: Reducing the Risk of Common Infections for more information.
  • If you have a cut, scrape, or wound, keep it clean and covered with a bandage until your skin has healed. 
  • Avoid contact with other people’s wounds or bandages.
  • Do not share personal items such as clothing, uniforms, towels or razors.
  • Clean the surfaces of shared equipment before and after use, such as at a sports event or gym.
  • Clean surfaces such as counter tops and door handles with a standard disinfectant on a regular basis. 

If you are visiting a person in a healthcare setting (such as a hospital or a long-term facility), you should:

  • Wash your hands frequently using soap and water or use alcohol-based hand cleansers.
  • Wear gloves and masks where appropriate.
  • Not touch the patient’s catheters or wounds.
  • Always wash your hands before you leave the person's room.

Outside of a healthcare setting, if you come in contact with a person who is infected or colonized (such as caring for an infected person in your home, or in a first aid situation), the CDC recommends the following precautions:

  • Caregivers should wash their hands with soap and water after physical contact with the person and before leaving the home.
  • Towels used for drying hands after contact should be washed before re-use.
  • Disposable gloves should be worn if contact with body fluids is expected. Hands should be washed after removing the gloves.
  • Bed sheets should be changed and washed if they are soiled, and on a regular basis.
  • The patient's environments should be cleaned routinely and when soiled with body fluids or feces.
  • Notify doctors and other health care personnel who provide care for the patient that the patient is colonized/infected with a drug-resistant organism.

What precautions might be in place if I work in a hospital?

Because a health care worker will help many patients during a shift, it is important to follow certain steps to control the spread of infection. You should check with your infection control department for any specific requirements.

In general, these methods include:

  • Isolation - where the patient is given their own room, or share a room with others that have the same infection.
  • Restrictions on where the patient can be transported or moved.
  • Gloves and hand washing - wear gloves and wash your hands after contact, especially contact with body fluids. You may have to change gloves and wash your hands between procedures on the same patient to prevent cross-contamination to different body sites.
  • Masks/gowns - depending on the level of contact with body fluids or feces, all or some of these protective clothing will be required.
  • Use equipment properly - make sure that any equipment used is appropriately cleaned, disinfected, or discarded. Surfaces of equipment in the patients room should also be cleaned and disinfected.
  • Special "dedicated" equipment may be required. Use of instruments such as stethoscopes, bedside commodes or thermometers may only be allowed with one patient or one group of patients.
  • Handle and clean laundry properly.
  • Special procedures may be in place for testing and active surveillance to monitor the infection (e.g., identifying carriers of organism when patients are admitted to the hospital and isolating the patients even though they do not present symptoms but are only colonized with bacteria).

Document last updated on December 3, 2013

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Although every effort is made to ensure the accuracy, currency and completeness of the information, CCOHS does not guarantee, warrant, represent or undertake that the information provided is correct, accurate or current. CCOHS is not liable for any loss, claim, or demand arising directly or indirectly from any use or reliance upon the information.