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By Pamela S. Falk, MPH
This article discusses strategies for preventing and controlling VRE.
The first infections due to vancomycin-resistant enterococci (VRE) were identified inEurope in 1986.1 Since that time, VRE have been identified in many countriesaround the world including the UK, France, Canada, and the US.1-3 Based on datafrom the Centers for Disease Control and Prevention's (CDC) National Nosocomial InfectionSurveillance (NNIS) system, the percentage of nosocomial infections caused by VRE between1989 and 1993 increased from 0.3% to 7.9%.4 Most of the reported cases werefrom intensive care units. In the past few years, VRE have also been isolated frompatients in general medical and surgical units and long-term care facilities.
Enterococci are part of the normal flora of the intestinal tract. Some species ofenterococci are relatively resistant to many commonly used antibiotics but until recenttimes have been sensitive to vancomycin. When enterococcal species with relativeresistance to other antimicrobial agents acquire vancomycin resistance, they have aselective advantage over other species in the normal flora, permitting them to replicatein the intestinal tract as the other species are eradicated by antimicrobial therapy. Ofthe patients who become colonized by VRE, only 1 in 10 will develop a clinical infection.VRE cause endocarditis, intravascular catheter-related infections, bacteremia, and urinarytract infections.
The colonized gastrointestinal tracts of hospitalized patients make up the mostimportant reservoir of VRE. To identify patients colonized by VRE, many healthcarefacilities have developed a surveillance program using cultures of perianal swabs onselective culture media. It has been noted that patients may remain colonized for weeks,months, or years after discharge from the hospital and may still be colonized at the timeof readmission to the hospital.
The hospital environment has been identified as a source of VRE. Surfaces such asbedrails, cardiac monitors, and bedside tables in the rooms of VRE patients are frequentlycontaminated by VRE. Environmental contamination occurs commonly in rooms of patients whohave VRE. It is particularly prevalent in rooms of patients who are incontinent of stoolor have diarrhea. Many VRE remain viable on surfaces from days to weeks because theorganism seems to be resistant to desiccation and extreme temperatures.
Contaminated hands of healthcare workers may transmit VRE directly between patients.Medical equipment and inanimate surfaces in the hospital environment are frequentlycontaminated with VRE. VRE may be transmitted between patients by the contaminatedsurfaces of medical equipment or when healthcare workers contaminate their hands bytouching environmental surfaces before they provide patient care.
Most patients colonized by VRE have been in intensive care units, transplant units, andoncology units. Risk factors for VRE acquisition identified in the literature includeduration of hospitalization, enteric feeding, and treatment with vancomycin, thirdgeneration cephalosporins, and sucralfate.5-7 We have recently identifieddiarrhea and administration of antacids as risk factors for acquisition of VRE in burnpatients.8
Based on the epidemiology of VRE in the healthcare setting, the Hospital InfectionControl Practices Advisory Committee (HICPAC) published control recommendations for VRE.
The infection control measures are as follows:
In addition to following the HICPAC guidelines it is essential that the environment ofa VRE patient be cleaned and disinfected daily. Items such as stethoscopes,sphygmomanometers, and rectal thermometers should be dedicated to each VRE patient. Avariety of healthcare workers, such as housekeepers, nurses, and respiratory therapistsmust share the responsibility for cleaning the patient's environment. A checklist may beused to ensure that all environmental surfaces and medical equipment are cleaned daily.The responsibilities for cleaning should be delineated clearly (Table 1).
If a patient is presented to the Emergency Department (ED) and is known to have VRE,control measures depend on the type of care to be rendered. If the patient presents withsignificant diarrhea, gown and gloves are recommended. However, this is no different thanfollowing the Standard Precautions that have been instituted at all healthcareinstitutions.
Since patients do not ordinarily spend as much time in an ED treatment room as theywould in an inpatient room, the environment does not have as much time to become heavilycontaminated with VRE. Timely and thorough cleaning and disinfection of environmentalsurfaces contaminated with stool is important for controlling VRE.
Patients should be at low risk for acquiring VRE from the OR. Healthcare workersroutinely wear gowns and gloves during the surgical procedure and work in a sterile field.Circulating personnel should wear gloves as necessary and wash their hands frequently. Theenvironment of the surgical suite should be cleaned between all cases.
While the floor of the OR, operating table, instrument tables, and mayo stands areusually cleaned between cases, items infrequently cleaned include the anesthesia cart andgas machine surfaces, monitor cables, bolsters, and the electrocautery unit. Managementshould assure that all the items that are used during a case are cleaned before the nextcase.
Medication carts with drawers with small partitions (commonly used by anesthesia) maypose a unique problem for VRE control. The medication cart should be cleaned anddisinfected between cases. It is recommended that the medications needed for a VRE case beremoved from the drawer prior to the procedure. Thus, the healthcare worker does not needto enter the drawer during the procedure and risk contaminating its contents with VRE. Ifa medication is needed that was not anticipated prior to the case, the healthcare workershould wash hands prior to entering the drawer (a waterless hand disinfection agent isacceptable). Therefore, with appropriate cleaning and handwashing, and the use of gownsand gloves, transmission should not occur in the OR.
At the University of Texas Medical Branch Hospital (Galveston, Tex), a patient with VREor any resistant organism is taken directly to the OR, recovered in the OR, and returneddirectly to the patient's room. While the post-anesthesia recovery room (PACU) is not ahigh-risk area for transmission of the organism, emergency situations do occur that mayrequire an invasive procedure. An invasive procedure on a VRE patient in the PACU mayincrease the risk of VRE transmission to another patient. If a VRE patient is recovered inthe PACU, a private room is recommended. The room should be cleaned thoroughly ondischarge of the patient.
Like the Emergency Room, patients with VRE need little special attention in theoutpatient clinic and surgical center, except following Standard Precautions. If a patientrequires procedures, such as endoscopy, hemorrhoidectomy, or perirectal abscess drainage,risk for transmission for VRE may be increased. However, if Standard Precautions arefollowed (wearing gowns and gloves for contact with patient body fluids) and the medicalequipment and environment are cleaned and disinfected thoroughly after use, additionalprecautions are not required for VRE patients.
Personnel who transport patients from place to place in the hospital have frequentcontact with many patients during the day. Good handwashing is essential for control ofnosocomial infections. Barriers are also important because transporters have closephysical contact with patients as they lift them from stretchers and wheelchairs into bedsand onto procedure tables. Therefore, the person transporting a VRE patient should wear agown and gloves. A sheet should be placed between the patient and the stretcher or thewheelchair. After transporting the patient, gowns and gloves should be removed and handswashed. The wheelchair or stretcher should be disinfected. The patient does not need towear a gown and gloves for transport.
Colonization of a patient by VRE is not a contraindication for discharge from thehospital. Once medically ready to be discharged, the patient may go home to a nursing homeor rehabilitation center. Prior to discharge of a VRE patient to another institution,hospital staff should inform personnel at the receiving facility that the patient iscolonized by VRE. Most facilities have programs to control VRE in their unique setting.
Many healthcare workers have become familiar with methicillin-resistant Staphylococcusaureus (MRSA). Patients infected or colonized with this organism are placed inisolation and treated with vancomycin as needed. Epidemiologists are concerned that thegenes that control antibiotic resistance in VRE will be transferred to MRSA. Infectionscaused by vancomycin-resistant Staphylococcus aureus (VRSA) would be very difficultto treat. Unlike enterococci, Staphylococcus aureus is a highly pathogenicbacterium, which is moderately contagious and causes infections such as endocarditis,bacteremia, surgical site infections, intra-abdominal abscesses, and pneumonia. It will bea public health nightmare if MRSA develop resistance to vancomycin.
VRE is a bacterium that is becoming more prevalent in patient populations. Patients intransplant units, oncology units, and intensive care units are at a higher risk ofacquiring VRE due to prolonged length of stay and treatment with multiple antibiotics.They are also frequently subjected to invasive procedures that place them at risk forcolonization with VRE. Healthcare workers in inpatient settings should care for VREpatients using barrier precautions, which includes use of gowns and gloves and handwashingbefore and after each patient contact. It is essential that all equipment used on VREpatients be cleaned daily to decrease microbial load. Equipment that is no longer neededfor a VRE patient must be decontaminated prior to use on the next patient. StandardPrecautions are appropriate for the ED, OR, PACU, and outpatient facilities.
Pamela S. Falk, MPH, is the Director of Healthcare Epidemiology at the University ofTexas Medical Branch (Galveston, Tex). The author would like to thank Janice Winnike, BSN,and the staff of the Department of Healthcare Epidemiology for their assistance with thedevelopment of Table 1 and C. Glen Mayhall, MD, for his overall guidance with thisarticle.
For references, access the ICT Web site.
Table 1: Routine Departmental Equipment Cleaning Responsiblities
|Items||Nursing||Pulmonary Care||Environmental Services||Monitoring* Services|
|Cardiac Monitors (leads, cables)||x|
|High-Pressure Infusion Bags||x|
|Portable Patient Scales||x|
|Vital Signs Monitors (rolling)||x|
|Airway Management Packs||x|
|Code Carts (after each use, daily)||x|
|Nitric Oxide Set Ups||x|
|Portable Pulse Oximeters||x|
|Respiratory Supply Carts||x|
|Oxygen and Air Flowmeters (wall mount)||x|
|IV Poles (hanging and rolling)||x|
|Sphygmomanometer (wall mount)||x|
|Suction Bottles/Suction Control Units||x|
|Enteral Feeding Pumps||x|
|IV Infusion Pumps||x|
|Over-bed Cradle/Traction Equipment||x|
|Portable Suction Machines||x|
|Sequential Compression Devices||x|
For a complete list of references click here