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ID - UREASE
USE
The Gibson ID -
Urease is designed for the detection of urease activity in a variety of
microorganisms.
PRINCIPLES
The
differentiation of microorganisms on the basis of urea hydrolysis has been widely used for
Enterobacteriaceae.1 -2
Urease hydrolizes urea into two
ammonia molecules. This causes an increase in the pH which can be detected by the
indicator, phenol red. A positive test produces a color change from yellow to pink or red.
MATERIALS
PROVIDED
10 Test
Cupules: Urea
1 Bottle Reagent: Phenol Red and
cofactor for Urease Enzyme
MATERIALS
REQUIRED BUT NOT PROVIDED
The
standard clinical microbiological equipment such as loop, burner, and incubator are needed
for procedures involving the use of this product.
PRECAUTIONS
This test
is intended for use by those trained in appropriate laboratory and bacteriological
procedures. This test is for IN VITRO DIAGNOSTIC USE only. Precautions should be taken
against the dangers of microbiological hazards. Specimens, containers, media, and test
cupules should be sterilized after use. Reagents should not come into contact with skin,
eyes, or clothing. Do not inhale or ingest reagents. In case of accident, seek medical
attention immediately.
STORAGE
The ID -
Urease kit must be stored at 2-8C to prevent breakdown of the substrates and reagents.
EVIDENCE OF
DETERIORATION
Substrates and reagents
provided with this kit should not be used if the expiration date has passed. Do not use
this product if a yellow color is not observed upon the addition of the reagent to the
substrate cupule. If any deficiencies are noted with this product notify the manufacturer.
SPECIMEN
COLLECTION
Information
on specimen collection can be found in reference texts.
PROCEDURE
1. Remove cap from
cupule and add 10 drops of reagent. Dried substrate may be dissolved by mixing with the
inoculating loop or stick in step #2.
2. Inoculate test medium in cup with
specimen by selecting 2-3 isolated colonies and mixing with loop to insure uniform
suspension of cells. Be sure to mix liquid well at this point with inoculating loop or
device to achieve dissolution of substrate.
3. Replace cap and place
cupule into reclosable plastic bag or into a rack.
4. Record patient information on bag
or on cup if rack is used.
5. Hold at room temperature and read
for color changes within 30 minutes.*See Limitation Section
INTERPRETATION
Positive: Pink to
red; urease present
Negative: Yellow (No change); urease
not present
USER QUALITY
CONTROL
Daily quality control should be
performed in accordance with proper laboratory procedures using
organisms that will produce known
positive and negative reactions. The following American Type
Culture Collection strains are
recommended:
Organism Test Cupule
Yersinia enterocolitica (4+) red
ATCC 9610
Proteus mirabilis (2+) red
ATCC 12453
Escherichia coil (-)yellow
ATCC 25922
LIMITATIONS OF PROCEDURE
The substrate medium is very
slightly buffered and the yellow color of the medium should not change upon the addition
of inoculum. Any color change to pink upon addition which persists over 30 minutes or
which develops at a later time may be attributed to urease activity. An inoculum of
culture colonies may result in immediate increase in pH and development of a red color due
to carryover of extraneous alkaline materials. This red color will fade to yellow and will
remain yellow unless urease activity is present.
When ID - Urease is used for
detection of urease activity in microbial cultures, it should be noted that some
microorganisms are more prolific producers of urease than others. Hence, specimens which
are negative after 30 minutes should be reexamined at convenient intervals for up to 24
hours. If desired, the cup may be sent to the laboratory for monitoring and/or
subculturing. The bag included in the kit provides a convenient transport method.
Bacterial overgrowth
from other organisms may be present that produce urease causing false positive results.
REFERENCES
1. Christensen, W.R., "Urea
Decomposition as a Means of Differentiating Proteus and Paracolon Cultures From
Each Other and From Salmonella and Shigella Types," J. Bact.
52:461-466, 1946.
2. Rustigan, R. and
C.A. Stuart, "Decomposition of Urea by Proteus," Proc. Soc. Exp. Biol.
Med., 47:108-122, 1941.
Catalog # 60045 |
