Just the facts: VRE a costly, resilient bug
The Centers for Disease Control and Preven tion distributed a fact sheet on vancomycin-resistant enterococci (VRE) as part of a recent satellite broadcast of a medical training program. The fact sheet included the following information, which is summarized below:
Etiologic agent: Enterococcus species, most commonly E. faecium and E. faecalis.
Transmission: Person-to-person by contact. Environmental contamination may be important.
Risk groups: Hospitalized persons with severe underlying or immunosuppressive conditions (e.g., oncology, surgery, or intensive care unit patients); the elderly, especially those in institutions (e.g., nursing homes); and persons with frequent exposure to vancomycin (e.g., dialysis patients).
Clinical features: VRE can cause infections at a variety of body sites, most commonly the urinary tract, surgical site, or bloodstream. Infections are characterized by fever and signs related to the specific focus of infection (e.g., pain, redness, and shock, etc.). Large numbers of VRE-colonized patients can serve as an unrecognized reservoir or source of infection. Colonization usually precedes infection.
Sequelae: Bloodstream infections (BSIs), sepsis, organ system failure, death (30% to 40% case-fatality rate). Some infections are virtually untreatable.
Costs: Direct medical costs (estimated at $18,000/hospitalization for a VRE BSI alone) include disruption to families and loss of earnings for those with a fatal outcome or long-term sequelae. Costs also include infection control and public health interventions to prevent spread of VRE in high-risk populations. VRE control measures are cumbersome but cost-effective (estimated annual hospital savings at one hospital for VRE BSI was $151,000 to $180,000/year).
Surveillance: Not a notifiable disease (except in Connecticut and Vermont). Nationwide surveillance through the National Nosocomial Infections Surveillance (NNIS) System.
Incidence: Unknown. From 1989 to 1996, NNIS data show that the percentage of enterococci causing nosocomial infections increased from 0.3% to 14.2%. In 35 hospitals in the San Francisco Bay area, the proportion of laboratories isolating > 1 VRE increased from approximately 19% in 1995 to 91% in 1996. In Connecticut, where VRE is reportable, the VRE incidence from 1994 to 1996 was 24.7 isolates per million population.
Trends: Increase in disease worldwide since 1988 when VRE was first reported. Data from outbreak investigations and the California Emerging Infections Program show rapid spread of VRE at health care facilities throughout the United States. During 1992 to 1995, VRE BSI increased from 11 to 29 per 100,000 admissions at 94 New Jersey Hospitals. In 1995, 11.5% of 2,634 U.S. dialysis centers reported > 1 VRE patient(s). Passive surveillance in Connecticut shows that marked under-reporting can occur.
Laboratory: First line of defense against the spread of VRE. Identification of enterococci includes Gram stain, PYR test, negative catalase tests, growth in presence of 6.5% salt, and colonial morphology. Definitive identification requires a motility test and examination for pigment. Currently, a broth microdilution test incubated for 24 hours is the most reliable method of testing enterococci for vancomycin resistance. Fully automated methods remain unreliable.
Research priorities: Perform laboratory investigations to identify cost-effective methods for rapid detection of VRE-colonized/infected patients. Assess the risk of asymptomatic VRE colonization. Identify effective treatments for VRE-infected patients. Develop and implement strategies to prevent VRE transmission in high-risk populations and settings.
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