Sorted By Test Name - Mayo Medical Laboratories

VRERP
84406
VANIL
82621
Therapy, Mayo Clinic, 2005-2008
Vancomycin-Resistant Enterococcus, Molecular Detection, PCR
Clinical Information: Vancomycin-resistant enterococci (VRE) are major nosocomial pathogens.
Patients who are particularly vulnerable to fatal disease from VRE include those with hematologic
malignancies and liver transplants. Nosocomial spread of VRE occurs as the result of fecal carriage. Risks
for both colonization and infection include prolonged hospitalization, intensive care unit stay,
transplantation, hematologic malignancies, and prolonged exposure to antibiotics. The Centers for Disease
Control and Prevention provides recommendations to prevent the spread of VRE in institutional settings.
These recommendations include isolation of patients experiencing active VRE infection, screening of
patients by perianal swab or fecal testing to identify carriers of VRE, and subsequent isolation or
cohorting of VRE carriers. Identification and isolation of VRE carriers has been shown to be
cost-effective. In Enterococcus faecalis or Enterococcus faecium, vancomycin resistance is usually
associated with the presence of the vanA or vanB genes. The presence of these genes is detected by a
molecular method in this assay.
Useful For: Identifying carriers of vancomycin-resistant enterococci
Interpretation: Positive test results indicate the presence of either the vanA or vanB gene, which
confers vancomycin resistance in Enterococcus faecalis and Enterococcus faecium (and occasionally other
organisms). Patients with a positive test result should be placed in isolation or cohorted with other
vancomycin-resistant enterococci (VRE) carriers according to the institution's infection control practices.
A negative result indicates the absence of detectable vanA or vanB DNA in the specimen but does not
rule out carrier status as false negative results may occur due to inhibition of PCR, sequence variability
underlying primers and/or probes, or the presence of VRE in quantities less than the limit of detection of
the assay. In the rare event that PCR testing appears to be negative but there is evidence of PCR
inhibition, the result will read "PCR inhibition present"; in such a case, a new specimen should be
submitted for repeat testing.
Reference Values:
Not applicable
Clinical References: 1. Sloan LM, Uhl JR, Vetter EA, et al: Comparison of the Roche LightCycler
vanA/vanB detection assay and culture for detection of vancomycin-resistant enterococci from perianal
swabs. Submitted J Clin Microbiol 2004;42:2636-2643 2. Vancomycin-resistant enterococci:
Colonization, infection, detection, and treatment. (November 2007). In Mayo Clinic, Mayo Medical
Laboratories Communique, Vol 32, No. 11 3. Zirakzadeh A, Patel R: Epidemiology and mechanisms of
glycopeptide resistance in enterococci. Curr Opin Infect Dis 2005; 18:507-12 4. Zirakzadeh A, Patel R:
Vancomycin-resistant enterococci colonization, infection detection and treatment. Mayo Clinic Proc
2006; 81:529-36 5. Patel R: Enterococcal-type glycopeptides resistance genes in non-enterococcal
organisms. FEMS Microbiol. Lett. 2000;185:1
Vanilla, IgE
Clinical Information: Clinical manifestations of immediate hypersensitivity (allergic) diseases are
caused by the release of proinflammatory mediators (histamine, leukotrienes, and prostaglandins) from
immunoglobulin E (IgE)-sensitized effector cells (mast cells and basophils) when cell-bound IgE
antibodies interact with allergen. In vitro serum testing for IgE antibodies provides an indication of the
immune response to allergen(s) that may be associated with allergic disease. The allergens chosen for
testing often depend upon the age of the patient, history of allergen exposure, season of the year, and
clinical manifestations. In individuals predisposed to develop allergic disease(s), the sequence of
sensitization and clinical manifestations proceed as follows: eczema and respiratory disease (rhinitis and
bronchospasm) in infants and children less than 5 years due to food sensitivity (milk, egg, soy, and wheat
proteins) followed by respiratory disease (rhinitis and asthma) in older children and adults due to
sensitivity to inhalant allergens (dust mite, mold, and pollen inhalants).
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