[Table of Contents]

Canada Communicable Disease Report - Supplement
Volume: 23S8
December 1997

INFECTION CONTROL GUIDELINES

Preventing the Spread of Vancomycin-Resistant Enterococci (VRE) in Canada

Overview of VRE

Our understanding of the epidemiology and natural history of colonization and infection with vancomycin-resistant enterococci (VRE) is evolving and will continue to evolve. Several studies suggest that VRE colonization is much more common than infection and that colonization may persist for months to years. Clearly, this has important implications for health care settings, where focusing of efforts on known colonized patients may miss the potentially larger number of unknown colonized patients who may serve as sources of transmission. A prolonged state of colonization also presents logistical problems with respect to the precautionary management of these patients as they move across the continuum of care (acute care, chronic care, and home care) and as their illness changes from symptomatic to asymptomatic. Special isolation/ precautionary techniques have had variable success in controlling the spread of VRE. While some studies have shown their usefulness in outbreak situations, others have not shown an impact. Thus, much remains to be learned about the effect of VRE in colonized patients, the factors that predict the risk of nosocomial spread, and identification of measures that will prevent that spread. The use of maximal precautions/techniques to prevent transmission in all settings is both impractical and expensive. The level of precautions used for a colonized/infected patient with VRE must take into consideration a risk assessment of the patient with respect to the likelihood of transmission (level of hygiene, continence, degree of illness, presence of co-morbid conditions) and the health care setting in which the patient is placed. An appropriate balance must be achieved to prevent nosocomial transmission and to avoid ostracizing the patient and gridlocking the health care system.

It is important to recognize that the risk factors for infection with VRE are related in part to the underlying illness of the individual. Although VRE bloodstream infections have been associated with high rates of mortality, the risk of death is most strongly related to the severity of the underlying illness rather than the VRE infection. The pathogenicity of vancomycin resistance in enterococci as a cause of mortality in patients with enterococcal bloodstream infections needs to be further assessed.

The recommendations in this document are rated according to the strength of the evidence supporting them and the quality of the supportive studies (see Appendix). The recommendations acknowledge the different situations that health care facilities must address and the different levels of precautions that may be required in varying circumstances. Although the emphasis of the recommendations is on meeting the needs of acute care facilities, long-term care facilities may also refer to them for assistance or to the Infection Control Guidelines for Long-Term Care Facilities⁽¹⁾. Additional assistance can be obtained by contacting the local public health personnel, who are available for consultation and may play an important role in developing an integrated approach to the control of antibiotic-resistant organisms (including VRE) in the community. Practitioners will have to apply these guidelines to suit their institutional needs. It is not possible to prevent all transmissions, and the benefit obtained from measures taken to reduce the risk of transmission must be balanced against the cost and feasibility of routine application of these measures. The guidelines in this document are based on current information and, as for other guidelines, may be modified as new information becomes available. VRE and other antibiotic-resistant organisms will be addressed in the revision of the Isolation and Precaution Techniques guidelines. The following discussion has been provided to organize and facilitate an understanding of VRE. The components to be discussed are:

1. Epidemiology of VRE

2. Microbiology of Enterococci

3. Antibiotic Resistance in Enterococci

4. Antimicrobial Susceptibility Testing of Enterococci

5. Risk Factors for VRE

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