Beckman Coulter MicroScan Manuel D'utilisation page 5

Well Reagent
IDX
AGL2 Add 1 drop of 0.05 N NaOH. Wait at least 5 seconds,
but no longer than 5 minutes before recording result.
BDF
Compare to the NPC control well.
AGAL
NAG
CELL
NGAL
1. A positive color may not be present throughout the entire well.
2. A pink color may be present with some yeasts. This should be considered a positive reaction.
PRINCIPLES OF IDENTIFICATION REACTIONS
Amino acid β-naphthylamide substrates (HPR, ILE, PRO, TYR, GLY, GGLY, GLAR, GLPR, AARG, LYAL, ALA, STY,
HIS) - When the substrate is hydrolyzed by the appropriate enzyme (usually an amino acid arylamidase), β-naphthylamine
is released. The β-naphthylamine is detected by the addition of p-dimethylaminocinnamaldehyde (in the Peptidase reagent)
which creates a complex that is pink to purple in color.
NOTE: The enzyme which cleaves an amino acid β-naphthylamide is an amino acid arylamidase. The term "aminopeptidase" is
frequently used as a synonym for arylamidase but actually represents an enzyme with different specificity (an aminopeptidase
cleaves the N-terminal amino acid from a peptide). An arylamidase and an aminopeptidase may hydrolyze the same amino acid
β-naphthylamide substrate. Thus, the panel is not necessarily measuring different and unique enzymes. A single arylamidase
may hydrolyze several amino acid β-naphthylamides.
Carbohydrates (SUC1, SUC2, TRE) - The utilization of sucrose and trehalose results in a pH drop which causes the
chlorophenol red to change from purple to yellow. These carbohydrate reactions are selective and may not conform to
conventional reactions.
Nitrophenyl Substrates (AGL1, BGL, BGAL, AGL2, BDF, AGAL, NAG, CELL, NGAL) - If the appropriate enzyme is present,
the substrate is cleaved releasing ortho- or para-nitrophenol. At alkaline pH, these compounds are yellow. If the reaction occurs
at an acidic pH, NaOH must be added after incubation before the results can be read. The wells may be either colorless or
pale yellow before the sodium hydroxide is added.
Indoxyl Phosphatase (IDX) - Indoxyl phosphate is cleaved by a phosphatase to release indoxyl. The indoxyl combines with
oxygen to form indigo blue which is an insoluble blue or blue-gray precipitate.
Urea (URE) - Urea is split by urease to form ammonia and carbon dioxide. The ammonia (in the form of ammonium carbonate)
causes a rise in pH which is detected by phenol red changing from yellow to red.
ORGANISM IDENTIFICATION
The MicroScan Rapid Yeast Biotype Codebook is used for the identification of unknown test organisms. This codebook has
been generated from MicroScan's data base for the tests included on the identification panel. The Yeast Codebook is based
on a computer analysis of the 27 tests on the Rapid Yeast Identification Panel. The test results are transformed into a 9 digit
biotype number for which the codebook lists a species identification and a cumulative relative probability of identification. All
possible identifications are printed in descending order of highest probability to a cumulative total of 99.9%.
Should a biotype number occur that cannot be found in the codebook, one should first suspect a procedural error; for example,
the biotype number has been added incorrectly or a reaction has been erroneously recorded. If the biotype number is correct,
then the possibility of a mixed culture should be checked and the organism should be re-tested, with special emphasis on using
a sufficiently turbid cell suspension. If retesting yields the same results, consult the Biotype Lookup Service on the Beckman
Coulter website or consult your local distributor.
LIMITATION OF THE PROCEDURE
1. Rapid Yeast Identification Panels are designed for identification of yeast and yeast-like organisms (e.g., Prototheca).
Care must be taken with organisms with excessive hyphal production.
2. Should more than one species identification be listed for a particular biotype number, supplemental tests may be
necessary. Accepted identification procedures of yeast and yeast-like organisms include colonial morphology, growth at
elevated temperature, pigment formation and color on phenoloxidase agar. Microscopic morphology on media designed
to elicit typical morphology can also aid in identification of these organisms. Refer to appropriate mycology reference
procedures. 5,6,7,8,9,10,11,12,13
3. Variation in chromogenic results may occur due to excessive over or under inoculation of the system. Each inoculum
must be compared to the turbidity standard to achieve the correct concentration of inoculum for optimum performance.
QUALITY CONTROL
The acceptability of the Identification substrates should be checked by testing organisms of known reactions. The results for
each reaction for the recommended MicroScan control organisms are found in the Quality Control Chart located in this manual.
C29879–AB
Positive
Any shade of
Blue
Any shade of
2
Yellow
5 of 141
Negative
Clear
Clear