Newsletter Vol. 29 No. 3

Prevention of Multidrug-Resistant Organism (MDRO) Emergence and Transmission

Samantha A. Broaders, Ph.D. and Mrudula Srikanth, M.Sc.
Advanced Measurement Sciences
Clorox Services Company


Basic Facts About MDRO
Multidrug resistant organisms (MDRO) are defined as bacteria that have become resistant to more than one class of antimicrobial agents and usually are resistant to all but one or two commercially available antimicrobial agents, complicating treatment of illnesses they cause.
The emergence of MDRO is increasingly recognized as a major public health threat based on data from the Centers for Disease Control and Prevention (CDC) costing the United States Healthcare system approximately 3.2 billion dollars annually with increasing mortality rates [7,15]. Currently, two-thirds of all healthcare-associated infections (HAIs) are caused by just six MDRO referred to by the acronym ESKAPE: Enterococcus species (vancomycin resistant - VRE), Staphylococcus aureus (methicillin resistant – MRSA, intermediate or resistant to vancomycin - VISA/VRSA), Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species (extended-spectrum beta-lactamase-producing gram-negative bacilli - ESBLs and fluoroquinolone- resistant P. aeruginosa) [8,12,21].

MRDO Transmission in Healthcare Facilities
As infection rates of MDRO continue to rise across North America it has become increasingly important to develop more effective infection control programs to reduce the incidence of MDRO-related HAIs. A primary route of MDRO transmission in healthcare facilities is via the hands of healthcare workers [3,14]. Additionally, however, exposure to contaminated patient-care items or high-touch surfaces such as blood pressure cuffs, toilets, bedside commodes, electronic rectal thermometers, bed rails, call buttons, furniture and improper gloving/glove removal technique have been implicated as infection sources [6,10,19].

Important Elements of an Effective Infection Control Program
Implementation of, and adherence to, infection control practices are key to preventing the transmission of infectious diseases in all healthcare facilities. Recommended practices that should be included in a comprehensive infection control program include, hand hygiene, appropriate antibiotic use, disinfection of the patient environment, standard precautions/ transmission-based precautions, administrative measures, surveillance and education. When followed properly, these practices can decrease MDRO transmission [5,11,13,14]. However, hand hygiene is the single most effective means of preventing the spread of all infections among hospital patients and personnel [2,4].

Hand Hygiene: As part of hand hygiene precautions, the following procedures should be followed:

  • Wash hands with soap and water when they are visibly dirty or soiled with blood or other body fluids. In doing so, wet hands first with water, apply soap to hands and rub them together vigorously for at least 15 seconds, covering all surfaces of the hands and fingers. Rinse hands with water and dry thoroughly with a disposable towel. Use towel to turn off the faucet.
  • If hands are not visibly soiled, an alcohol-based hand rub or gel may be used in place of soap and water. Apply product to the palm of one hand and rub hands together, covering all surfaces of hands and fingers, until the hands are dry.
  • Avoid wearing artificial fingernails when caring for patients at high risk for infection, and keep natural nail tips less than 1/4-inch long.
  • Wear gloves when contact with blood, mucous membranes, non-intact skin, or other potentially infectious materials could occur. Remove gloves after caring for a patient. Always perform hand hygiene after removing gloves. Never wear the same pair of gloves for the care of more than one patient. Change gloves during patient care if moving from a contaminated body site to a clean body site.

Appropriate Antibiotic Use: The appropriate and prudent use of antibiotics is a key component in controlling MDRO. The CDC provides guidance for judicious use of antimicrobials and tools for implementation [1]. This effort targets all healthcare settings including long term care and focuses on effective antimicrobial treatment of infections, use of narrow spectrum agents, avoiding excessive duration of therapy and restricting use of more potent antibiotics to the treatment of serious infections [16].

Environmental Measures: The CDC recommends cleaning and disinfecting surfaces and equipment that may be contaminated with pathogens, including those that are in close proximity to the patient and frequently touched surfaces in the patient care environment [12]. Although MDRO are resistant to many antibiotics, they are sensitive to properly used Environmental Protection Agency (EPA) - registered disinfectants with claims for the species. Moreover, no data are available that show that antibiotic-resistant bacteria are less sensitive to liquid chemical germicides than the antibiotic-sensitive bacteria at currently used germicide contact conditions and concentrations [22]. During a suspected or proven MDRO outbreak where an environmental reservoir is suspected the following steps should be taken:

  • Routine cleaning procedures should be reviewed along with assessment for need for additional trained cleaning staff.
  • Adherence should be monitored and reinforced to assure consistent and correct cleaning is performed.
  • Room cleaning of patients on contact precautions should be prioritized. Bath tubs, whirlpools, and hydrotherapy tubs should be cleaned and disinfected after each use.

EPA-registered disinfectants or detergents/disinfectants that best meet the overall needs of the healthcare facility for routine cleaning and disinfection should be selected [9,18]. These products, which include sodium hypochlorite and quaternary ammonium chloride disinfectants must always be used as recommended by the manufacturer with particular attention being paid to compliance with directions for dilution (if applicable) and contact time with the surface to be disinfected. A list of EPA registered disinfectants may be obtained by calling the National Pesticide Information Center at 800-858-7378 or by visiting

Standard Precautions/Transmission-Based Precautions: These require the use of work practice controls and protective apparel for all contact with blood and body substances, and airborne infection isolation, droplet, and contact precautions for patients with diseases known to be transmitted in whole or in part by those routes [20].

Administrative Measures: Interventions include providing the appropriate number and placement of hand washing sinks and hand sanitizer dispensers, maintaining appropriate staffing levels and enforcing adherence to recommended infection control practices.

Education: Patient care and environmental services staff should receive education and training regarding MDRO and the importance of transmission prevention. Patients, families, and visitors should be educated about MDROs, necessary precautions (importance of hand hygiene), and their own potential for colonization. In-service training in infection control should be provided in response to any increase in MDRO frequency within the facilities.

Surveillance: Surveillance should include maintaining a confidential line listing of residents colonized and/or infected with targeted MDROs. Monitoring culture and antibiotic susceptibility data will help determine baseline rates for MDROs in a facility, indicate the occurrence of increased transmission, and monitor the effectiveness of outbreak control measures [5].

MDROs present a unique and growing challenge to healthcare providers and institutions. HICPAC recommends fastidious environmental cleaning and disinfection of patient care items and environmental surfaces to reduce bacterial load and risk of transmission [6,14]. Additionally, good antimicrobial stewardship complements infection control efforts and environmental interventions to provide a more comprehensive strategy to prevent and control outbreaks of MDROs. Successful outcomes are usually based on a combination of the multiple interventions outlined above [12,14,16].

6. 5 Million Lives Campaign, How-to Guide: Reduce Methicillin-Resistant Staphylococcus aureus (MRSA) Infection,
7. Ballard, J et al. Battling “Superbugs” in the Environment of Care (Feb 2007). The Joint Commission Environment of Care News, Vol 10, Num 2, pg 1-4.
8. Boucher, HW et al. No ESKAPE! New Drugs Against MRSA, Other Superbugs Still Lacking. ISDA Web Reference. Bad Bugs, No Drugs: No ESKAPE! An Update from the Infectious Diseases Society of America. Clinical Infect Dis. 2009; 48:1-12.
9. CDC. Guidelines for Environmental Infection Control in Health-Care Facilities. Recommendations of CDC and the Healthcare Infection Control Practices Advisory Committee (HICPAC). MMWR 2003;52 (RR10);1-42.
10. Clostridium difficile. In: Guidelines for Environmental Infection Control in Health-Care Facilities. Centers for Disease Control and Prevention, Healthcare Infection Control Practices Advisory Committee. U.S. Department of Health and Human Services. 2003; 84-85.
11. Guidelines for Prevention and Control of Infections Due to Antibiotic- Resistant Organisms, March 2010, Florida Department of Health Division of Disease Control Bureau of Epidemiology 850.245.4401
12. Jane D. Siegel, MD; Emily Rhinehart, RN MPH CIC; Marguerite Jackson, PhD; Linda Chiarello, RN MS; the Healthcare Infection Control Practices Advisory Committee, Management of Multidrug-Resistant Organisms In Healthcare Settings, 2006.
13. Kelley L., Mater Manag Health Care. 2008 Jun; 17(6):34-6. How to win the MDRO battle.
14. Massachusetts Department of Public Health. (2009) Multidrug Resistant Organisms- Infection Control Guidelines for Long Term Care Facilities.
15. Milstone AM, Bryant KA, Huskins WC, Zerr DM.,The past, present, and future of healthcare-associated infection prevention in pediatrics: multidrug-resistant organisms. Infect Control Hosp Epidemiol. 2010 Nov; 31 Suppl 1:S18-21.
16. Nimalie D. Stone, Managing MDRO’s in LTC: Strategies across care transitions,
17. Philip W. Smith MD, Gail Bennett RN, MSN, CIC, Suzanne Bradley MD, Paul Drinka MD, Ebbing Lautenbach MD, James Marx RN, MS, CIC, Lona Mody MD, Lindsay Nicolle MD and Kurt Stevenson MD., SHEA/APIC Guideline: Infection Prevention and Control in the Long-Term Care Facility, July 2008, Infection Control and Hospital Epidemiology, Vol. 29, No. 9 (September 2008), pp. 785-814
18. Rutala WA, Weber DJ. Disinfection and sterilization in health care facilities: What clinicians need to know. Clin Infect Dis 2004;39 (5):702-9.
19. Rutala WA. Environmental Control to Reduce Hospital GI Illness. Presented at: 16th Annual Scientific Meeting of the Society for Healthcare Epidemiology of America. Chicago, IL. March 20, 2006.
20. Siegel JD, Rhinehart E, Jackson M, Chiarello L, and the Healthcare Infection Control Practices Advisory Committee, 2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings, June 2007.
21. Washington State Department of Health. (2008) Evidence-Based Monitoring Strategies and Interventions for Antibiotic Resistant Organisms.
22. William A. Rutala, Ph.D., M.P.H., David J. Weber, M.D., M.P.H. and the Healthcare Infection Control Practices Advisory Committee (HICPAC), CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008,

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