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HelpTest Code VRERP Vancomycin-Resistant Enterococcus, Molecular Detection, PCR, Varies
Reporting Name
VRE PCRUseful For
Identifying carriers of vancomycin-resistant enterococci
Method Name
Real-Time Polymerase Chain Reaction (PCR)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
VariesNecessary Information
Specimen source is required.
Specimen Required
The high sensitivity of amplification by polymerase chain reaction requires the specimen to be processed in an environment in which contamination of the specimen by vancomycin-resistant Enterococcus DNA is unlikely.
Submit only 1 of the following specimens:
Preferred:
Specimen Type: Perianal, perirectal, rectal, anal
Supplies: Culturette (BBL Culture Swab) (T092)
Container/Tube: Culture transport swab (Dacron or rayon swab with aluminum or plastic shaft with either Stuart or Amies liquid medium)
Specimen Volume: Swab
Specimen Stability Information: Refrigerated (preferred)/Frozen
Acceptable:
Specimen Type: Preserved feces
Supplies: Culture and Sensitivity Stool Transport Vial (T058)
Container/Tube: Commercially available transport system specific for recovery of enteric pathogens from fecal specimens (15 mL of non-nutritive transport medium containing phenol red as a pH indicator, either Cary-Blair, Para-Pak C and S vial)
Specimen Volume: Representative portion of feces
Collection Instructions:
1. Collect fresh feces and submit 1 gram or 5 mL in container with transport medium.
2. Place feces in preservative within 2 hours of collection.
Specimen Stability Information: Ambient (preferred)/ Refrigerated
Specimen Type: Unpreserved feces
Supplies:
-Stool Container, Small (Random), 4 oz Random (T288)
-Stool Collection Kit, Random (T635)
Container/Tube: Fecal container
Specimen Volume: Representative portion of feces
Collection Instructions: Collect fresh fecal specimen and submit representative sample in fecal container.
Specimen Stability Information: Refrigerated (preferred)/Frozen
Specimen Minimum Volume
See Specimen Required
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Varies | ||
Reject Due To
| E-swab, calcium alginate or, cotton-tipped swab Swab sent in gel transport medium, viral or universal transport medium Dry swab Formalin or PVA fixative |
Reject |
Reference Values
Negative
Day(s) Performed
Monday through Sunday
CPT Code Information
87500
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| VRERP | VRE PCR | 62261-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| SRC60 | Specimen source | 31208-2 |
| 84406 | VRE PCR | 62261-3 |
Test Classification
This test was developed using an analyte specific reagent. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.Clinical Information
Vancomycin-resistant enterococci (VRE) are major nosocomial disease-causing bacteria. 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 E faecium, vancomycin resistance is usually associated with the presence of vanA or vanB. The presence of these genes is detected by a molecular method in this assay.
Interpretation
Positive test results indicate the presence of either vanA or vanB, which confer vancomycin resistance in Enterococcus faecalis and Enterococcus faecium (and occasionally other organisms). Patients with a positive test result should be placed in isolation or t 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 but does not rule-out carrier status and may occur due to inhibition of polymerase chain reaction (PCR), sequence variability underlying primers or probes, or the presence of VRE DNA 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 cases, a new specimen should be submitted for repeat testing.
Cautions
A positive result does not imply the presence of vancomycin-resistant enterococci (VRE) disease; the presence of vanA or vanB correlates with colonization by VRE. Colonization with VRE is not associated with any signs or symptoms.
vanA or vanB may occasionally be found in organisms other than enterococci.
Supportive Data
Perianal swabs (894) were evaluated for the presence of vanA or vanB DNA by the vancomycin-resistant enterococci (VRE) polymerase chain reaction (PCR) assay and compared to culture using selective and differential media. Compared to culture the VRE PCR assay was 98% sensitive and 98% specific. The VRE PCR assay detected 35 more positive specimens than the culture method. No cross-reactivity was seen when tested on a panel of disease-causing and normal microbiota bacteria of the gastrointestinal tract. Enterococcus species containing the vanC gene were not detected with the VRE PCR assay.
Method Description
Bacterial DNA is extracted from the specimen. Using the LightCycler instrument and fluorescent energy transfer probes, vanA and vanB genes responsible for vancomycin resistance in enterococci are detected directly from perianal swabs or fecal specimens.(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. J Clin Microbiol 2004 Jun;42(6):2636-2643. doi: 10.1128/JCM.42.6.2636-2643.2004; Hefazi M, Damlaj M, Alkhateeb HB, et al: Vancomycin-resistant Enterococcus colonization and bloodstream infection: prevalence, risk factors, and the impact on early outcomes after allogeneic hematopoietic cell transplantation in patients with acute myeloid leukemia. Transplant Infect Dis. 2016 Dec;18(6):913-920. doi: 10.1111/tid.12612)
Report Available
1 to 4 daysSpecimen Retention Time
Swab transport media: 3 days; C and S vial: 7 daysForms
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.