Download Vancomycin Resistant Screen Agar (VSA)

Russell County Hospital
1610 Dowell Road
Russell Springs, KY 42642
270-866-4141
DEPARTMENT:
Laboratory
POLICY/PROCEDURE TITLE
Vancomycin Resistant Screen Agar (VSA) Enterococcus species
POLICY/PROCEDURE NUMBER:
400-PE-MIC-163
Issued: 5/1/06
Revised:
Supercedes:
Prepared by: R. Johnson
Approved:
Reviewed:
Medical Director
Approved:
Reviewed:
Laboratory Director
_________________________________________________________________________________________________
I.
PRINCIPLE. Enterococci are common, gram-positive bacteria that are normally found in the
bowel and in the female genital tract. Enterococci are hardy organisms and tolerate a wide
variety of growth conditions including temperatures of 10o-45oC, as well as hypotonic, hypertonic,
acidic or alkaline environments. These bacteria can be spread by fecal-oral transmission, contact
with infected body fluids or contact with contaminated surfaces. Enterococci account for
approximately 110,000 urinary tract infections, 25,000 cases of bacteremia, 4000 wound
infections, and 1100 cases of endocarditis in the United States yearly. Two species of
enterococci are responsible for most human enteroccocal infection. E. faecalis accounts for 8590% of all enterococci identified, but is less likely to develop resistance to vancomycin. E.
faecium accounts for 5-10% of all enterococcal infections and is more likely to develop
resistance. Suspected enterococci are set up using a gram-negative Microscan panel which will
identify the organism and give a presumption vancomycin susceptibility or resistance. Whenever
an enterococcus has been identified by Microscan as being resistant to vancomycin, the
organism must be set up on Vancomycin Screening Agar to confirm resistance before a final
report is generated.
II.
SPECIMEN.
A. Pure culture of 4-5 colonies of enterococcus of similar morphology grown overnight (18-24
hrs) on BAP.
B. HANDLE ALL SPECIMENS AND CONTAMINATED MATERIALS AS POTENTIALLY
BIOHAZARDOUS AND USE STANDARD PRECAUTIONS IN ACCORDANCE WITH
HOSPITAL AND LABORATORY SAFETY AND INFECTION CONTROL POLICIES.
I.
REAGENTS/SUPPLIES/EQUIPMENT.
A. Protective gloves.
B. Vancomycin screening agar.
1. Store at 2-8C and allow the plates to come to room temperature before plating.
2. Do not use medium if it is contaminated, if it is cracked or split due to drying, or if expired.
3. For in vitro diagnostic use only.
C. Sterile swabs.
D. Ambient incubator, 35C +/- 2C.
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Russell County Hospital
Policy/procedure name: Vancomycin Resistant Screen Agar (VSA) – Enterococcus species
Policy/procedure number: 400-PE-MIC-163
Issued: 5/01/06
Revised:
_________________________________________________________________________________________________________
II.
QUALITY CONTROL.
A. Quality control must be performed at least once each day of patient testing, and when a new
lot number or shipment is put into use, using the following organisms:
1. Enterococcus faecium, ATCC 51299 – resistant to vancomycin (VRE).
2. Enterococcus faecalis, ATCC 29212 – susceptible to vancomycin.
B. QC organisms must be tested in the same manner as unknown test organisms. Do not
accept test results without valid QC results. Document all QC results in the QC logbook.
C. HANDLE ALL CONTROL ORGANISMS AND CONTAMINATED MATERIALS AS
POTENTIALLY BIOHAZARDOUS AND USE STANDARD PRECAUTIONS IN
ACCORDANCE WITH HOSPITAL AND LABORATORY SAFETY AND INFECTION
CONTROL POLICIES.
III.
PROCEDURE.
A. Inoculate a room-temperature VSA from one of the following:
1. A drop of the bacterial suspension prepared for the Microscan ID and susceptibility.
2. A bacterial suspension prepared by immersing suspected colonies into sterile water and
adjusting turbidity to a 0.5 McFarland standard.
B. Incubate the plate at not more than 35C in an ambient incubator and observe for growth at
24 hours.
1. Growth - the strain is resistant vancomycin.
2. No growth - the strain is susceptible to vancomycin.
3. Correlate results from the Microscan panel with the VSA results to ensure they match.
IV.
REPORTING OF RESULTS.
A. Enter results in LIS when final results are obtained.
B. Ensure caregiver and infection control nurse are notified.
V.
REFERENCE.
A. BBL Product Information for Plated Media, Vancomycin Screening Agar, 7/2003.
B. Download from http://www.nursingceu.com/NCEU/courses/vre/.
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