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JOURNAL OF CLINICAL MICROBIOLOGY, Mar. 1982, p. 419-424 Vol. 15,
No. 30095-1137/82/030419-06$02.00/0
Evaluation of the Enteric-Tek System for
IdentifyingEnterobacteriaceae
A. 0. ESAIAS,* D. L. RHODEN, AND P. B. SMITHCenter for
Infectious Diseases, Centers for Disease Control, Atlanta, Georgia
30333
Received 26 June 1981/Accepted 5 October 1981
The Enteric-Tek wheel (Flow Laboratories), consisting of 14
different biochem-ical parameters for rapidly identifying
Enterobacteriaceae, was evaluated andcompared with the conventional
method for completely identifying 301 entericcultures, representing
36 species. The Enteric-Tek system correctly identified 264(97.8%)
of the 270 common or typical strains and 26 (83.9%) of the 31
unusual oratypical strains tested, demonstrating an overall
identification accuracy rate of96.3%. There were 80 (26.6%)
correctly identified strains requiring additionaltests. Of the 11
(3.6%) misidentifications, 5 (3 Klebsiella and 2 Salmonella
strains)were correctly identified at the genus level. When 4,228
individual tests in theEnteric-Tek wheel were compared with the
conventional tubed media, 96.4% ofthe tests agreed; urease,
citrate, adonitol, and lactose agreed less than 97%. TheEnteric-Tek
system was found to be reliable and accurate in producing
identifica-tions at the genus and species level within 18 to 24
h.
Since a substantial proportion of the workloadgenerated in the
clinical microbiology laboratoryinvolves isolating and identifying
Enterobacteri-aceae, the development of rapid identificationsystems
for enteric bacteria has increased, asevidenced by the numerous
commercially avail-able kits (2, 14). Many of these systems
havebeen studied and evaluated by various investiga-tors. A new
commercial identification system,the Enteric-Tek wheel (Flow
Laboratories, Ros-lyn, N.Y.), is designed to identify the
Entero-bacteriaceae at the genus and species levelwithin 18 to 24 h
of isolation on primary platingmedia. By the use of 14 different
biochemicalparameters, the system generates a five-digitoctal
profile number derived from the biochemi-cal reactions. In our
study, interpretation of thereactions was made according to the
manufac-turer's recommendations so an identificationcould be
derived from the computer code book.The purpose of this evaluation
was to deter-
mine the ability of the Enteric-Tek system toidentify both
typical and atypical members ofEnterobacteriaceae. This study
presents datawhich describe the performance and accuracy ofthe
Enteric-Tek wheel as compared with a con-ventional identification
system.
MATERIALS AND METHODSBacterial cultures tested. We tested 301 of
our stock
cultures from the General Bacteriology Laboratory,Centers for
Disease Control, culture collection. Thesecultures had been
assigned code numbers by a thirdparty. The selected cultures, well
distributed among 36species, included 270 common or typical strains
and 31
unusual or atypical strains. All cultures were main-tained in
sealed Trypticase (BBL Microbiology Sys-tems, Cockeysville, Md.)
soy agar stabs and stored atrodm temperature in the dark. Each
culture had previ-ously been identified by conventional procedures
(5,8-11). The identity of each culture remained unknownuntil all
results were compiled and the testing wascompleted.
Conventional method for identification. Each culturewas streaked
onto a MacConkey agar plate and ablood agar plate. Cultures were
then identified byconventional biochemical tests (5, 8-10). The
conven-tional tests routinely performed included reactions ontriple
sugar iron agar (H2S production); Christensenurea agar; indole;
methyl red; Voges-Proskauer (VP)medium; citrate; lysine and
omithine decarboxylase;arginine dihydrolase; motility;
phenylalanine; malon-ate; o-nitrophenyl-o-D-galactopyranoside; and
pro-duction of acid from glucose, lactose, sorbitol, dulci-tol,
inositol, adonitol, mannitol, sucrose, salicin,arabinose,
raffinose, and rhamnose. These media wereinoculated from culture
suspensions in tryptone brothand were incubated at 35C. After 18 to
24 h ofincubation, reagents were added for indole, methylred, VP
(acetoin), and phenylalanine tests. Testswhich were not positive
within 18 to 24 h wereobserved for a maximum of 7 days. When
required,additional tests were performed to complete the
identi-fication, e.g., growth in KCN and serological confir-mation
of Salmonella and Shigella. All cultures wereidentified by the
nomenclature and taxonomy de-scribed by Edwards and Ewing (8, 9)
and Brenner etal. (5). When necessary, the Enterobacteriology
Sec-tion, CDC, was consulted as a reference laboratory.
Enteric-Tek system. The Enteric-Tek system is around,
multicompartment wheel, consisting of a cen-tral well and 11
individual peripheral wells, all ofwhich contain solid media. The
system provides for
419
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420 ESAIAS, RHODEN, AND SMITH
determining 14 different biochemical parameterswhich include:
indole production; tryptophan deami-nase; H2S production; citrate;
malonate; lysine andornithine decarboxylase; urease; and acid
productionfrom glucose, lactose, rhamnose, adonitol, sorbitol,and
arabinose. All organisms tested were inoculatedonto MacConkey agar
and blood agar plates andincubated for 18 to 24 h at 35°C. A
suspension fromseveral well-isolated colonies of each organism
wasmade in 2 ml of sterile distilled water. Before inocula-tion,
the wheels were allowed to warm to roomtemperature and were labeled
appropriately. Inocula-tion was done as described in the detailed
instructionsprovided by the manufacturer. Each wheel was placedin
an upright position, incubated at 35°C for 18 to 24 h,then removed
from the incubator, and observed forcolor changes in the solid
media. The only manipula-tion required to observe a biochemical
reaction in-volved rolling a cotton swab saturated with a
specialindole reagent (Flow Laboratories) over growth in thecenter
well. Any redness developing within 30 s indi-cated a positive
indole reaction. The remainder of thewells were visually observed,
and their color was read,as suggested by the manufacturer. All
reactions wererecorded on a printed form and tabulated into a
five-digit profile number for identifying organisms listed inthe
manufacturer's code book. The data incorporatedinto the computer
code book were generated from thepercentage charts of Edwards and
Ewing (8) and fromin-house studies. Identification was based on the
prob-ability that a set of biochemical reactions would occurwith
more likelihood for one particular organism thanfor another and
allowed for the possibility of atypicalreactions. The code book
lists additional biochemicaltests required to complete an
identification. The addi-tional tests include: arginine,
cellobiose, DNase, escu-lin, gas from glucose, inositol, Jordan
tartrate, potassi-um cyanide, maltose, mannitol, methyl red,
motility,raffinose, VP, xylose, and serology for Salmonella
andShigella.
RESULTSAgreement of tests. Biochemical reactions for
the various tests in the Enteric-Tek system werecompared with
those obtained by the conven-tional method. Of the 14 common tests,
10showed more than 97% agreement with theirconventional
counterparts, whereas urease, ci-trate, adonitol, and lactose
agreed 83.4, 91.4,94.0, and 94.4%, respectively.These four tests
comprised 75% of all of the
test discrepancies. Certain groups of organismswere responsible
for lowering the agreement forsome of the tests. The 50 differences
in theurease test, all false-positive in the Enteric-Teksystem
except for 1, occurred with 6 Citrobacterfreundii, 10 Citrobacter
diversus, 14 Citrobacteramalonaticus, 4 Klebsiella pneumoniae, 4
Kleb-siella oxytoca, 8 Enterobacter cloacae, 1 Hafniaalvei, 1
Morganella morganii, and 1 Yersiniaenterocolitica strain. One
Proteus rettgeri straingave a false-negative reaction despite a 4+
reac-tion in the conventional Christensen urea agarslant. The 26
citrate test discrepancies included
22 false-negatives and 4 false-positives but werenot responsible
for any misidentifications. Ofthe 18 differences in the adonitol
test, all of the11 strains of Serratia marcescens, 1
Serratialiquefaciens, 1 K. pneumoniae, 1 Shigella flex-neri, 2
Yersinia pseudotuberculosis, and 1 Y.enterocolitica strain were
false-positive, butonly 2 of the latter 3 cultures were
misidentified.One false-negative adonitol reaction occurredwith a
Providencia alcalifaciens strain. The 17discrepancies in lactose
were divided almostequally between the false-negative (9) and
false-positive (8) reactions. Differences in the lactoseresults did
not change the identifications.
Identification. Overall, the Enteric-Tek sys-tem correctly
identified, at the genus and specieslevel, 96.3% of the 301 strains
tested. As shownin Table 1, the system correctly identified
264(97.8%) of the typical strains and 26 (83.9%) ofthe atypical
strains. Of the 290 cultures correctlyidentified, 62 of 270 typical
strains (23.0%) and18 of 31 atypical strains (58.1%) required
addi-tional tests. The number of additional testsranged from one
test for 7 strains, two tests for42 strains, and three tests for 30
strains, to fivetests for 1 atypical Escherichia coli strain.
Weperformed the suggested additional tests whenan identification
was given with less than 95%probability. Although correct
identifications forone Arizona hinshawii, one S. flexneri,
twoShigella boydii, and one Y. enterocolitica werelisted as
first-choice identifications, serologicalconfirmation was required
because the givenprobabilities were less than 95%.
Twenty-onestrains required serological confirmation be-cause the
assigned identifications were listed assecond, third, and fourth
choices in the codebook.The identification accuracy of individual
spe-
cies by the Enteric-Tek system is shown inTable 2. The system
provided 252 (86.9%) of thecorrect identifications as the first
choice. Therewere 38 identifications listed as second, third,
orfourth choices (29 as second, 6 as third, and 3 asfourth). The
Enteric-Tek system correctly iden-tified 100% of the strains for 29
of 36 species(80.6%) tested. The number of strains tested foreach
species ranged from 2 to 14, except for 25E. coli strains, which
included H2S-positive andatypical strains. Two atypical strains of
both E.coli and C. freundii were misidentified, decreas-ing their
identification rates from 100% to 92 and82%, respectively. Four
strains each of Salmo-nella paratyphi A, Salmonella typhi, and
Y.enterocolitica were tested; one strain of eachwas misidentified,
resulting in a 75% identifica-tion rate for each species. The
misidentifiedstrain of S. typhi was atypical. Both
Salmonellastrains were identified as S. enteritidis, listed asthe
second choice in the manufacturer's comput-
J. CLIN. MICROBIOL.
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EVALUATION OF THE ENTERIC-TEK SYSTEM 421
TABLE 1. Summary of identifications of unknown cultures with the
Enteric-Tek system
Organism category No. tested No. correct No. correct
requiringOrganismcategoryNo. tested
~~~~~~~~~~~~~~additionaltests'Common or typical 270 264 (97.8)b 62
(23.0)cUnusual or atypical 31 26 (83.9) 18 (58.1)Total 301 290
(96.3) 80 (26.6)
a Including Salmonella and Shigella serology when required.b
Number in parentheses gives the percentage for the category.c
Number in parentheses indicates the percentage of the number
correct in the category.
er code book. Klebsiella ozaenae, with ninestrains tested,
showed the lowest identificationrate (66.6%), because three strains
did not meetthe expected species level of identification, asclaimed
by the manufacturer.
DISCUSSIONIn comparison with the conventional meth-
ods, the Enteric-Tek system demonstrated ahighly acceptable
level of identification accura-cy for the 301 stock cultures
tested. The overallidentification rate of the Enteric-Tek
system(96.3%) compares favorably with the Micro-media' System (97%)
and Entero-Set 20 (96%)and is better than the Micro-ID (94%), API
20E(92%), and Enterotube (84%) systems wheneach system is compared
with conventionalmethods (2, 14). Another study reported a
higheridentification rate (97%) for both the API 20Eand Micro-ID
systems (3). Thirty-six entericspecies were tested with the
Enteric-Tek wheel,as compared with 21 to 28 enteric species
testedwith the other rapid identification kits. For iden-tifying a
large variety of enteric bacterial strainsto the species level, the
Enteric-Tek systemshows potential advantages over some of therapid
systems previously evaluated (2-4, 6, 14).The Enteric-Tek system
can correctly identifySerratia strains as to species, whereas the
API20E system has frequently been reported toidentify them at the
genus level only (4, 14).Additionally, a test for adonitol
fermentation isincluded in this system, as in the Micro-ID
andEntero-Set 20 but not in API 20E, allowing forthe
differentiation of H2S-negative C. freundiifrom C. diversus without
the need for additionaltests (4). Unlike the Micro-ID data base,
theEnteric-Tek system includes identification forEnterobacter
gergoviae and C. amalonaticusstrains (6).
Additional species of varied levels of difficultywere used in
this study, and the Enteric-Teksystem correctly identified all
strains for 29 of 36species (81%) tested. By comparison, 20
entericspecies were tested against the following rapidsystems, with
the indicated number of specieshaving all of their strains
correctly identified: theMicro-Media system with 17 (85%),
Micro-ID
with 13 (65%), Enterotube with 12 (60%), andAPI 20E with 11
(55%) (14). The scope of theEnteric-Tek system data base was
demonstratedby the 185 different profile numbers generated
inderiving the identifications, with a range of 1 to 9different
profile codes for each species tested.The Enteric-Tek system showed
the ability toidentify two new Serratia species, S. fonticolaand S.
odorifera. This ability was clearly shownwhen the one S. odorifera
strain tested wascorrectly identified as a first-choice
identifica-tion, having a 87.71% probability. Also, with 8of 10
correctly identified Enterobacter aero-genes strains, the
Enteric-Tek system listed S.fonticola, E. aerogenes, and S.
odorifera, in thatorder, as first-, second-, and third-choice
identi-fications. E. aerogenes was given as a second-choice
identification, showing a 47.07% proba-bility, as compared with S.
fonticola (52.91%)and S. odorifera (0.02%). In both of these
situa-tions, two additional tests, VP and DNase, weresuggested by
the manufacturer to easily differen-tiate these species. All S.
fonticola strains arelisted as VP negative, whereas all E.
aerogenesstrains are VP positive. All strains for both S.fonticola
and E. aerogenes have been shown tobe DNase negative, whereas all
S. odoriferastrains are DNase positive. Strains of S. fonti-cola
have been isolated from water samples andreported as
Citrobacter-like bacteria with lysinedecarboxylase production (12).
Researchershave reported that with commercial identifica-tion
systems, S. odorifera may look like atypical(gelatin-positive,
anaerogenic) E. aerogenes. S.odorifera strains are nonpigmented and
have acharacteristic odor that resembles the smell ofvegetable
matter, which is helpful in making acorrect identification. Strains
of S. odoriferahave been recovered from clinical specimensand may
be clinically significant because of thestrains studied (13).The
reasons for the 11 (3.6%) erroneous iden-
tifications (Table 3) were as follows: 3 (27.3%)resulted from
reaction discrepancies, 5 (45.4%)displayed aberrant biochemical
patterns, and 3(27.3%) required insufficient additional tests.
Asshown in Table 4, the three reaction discrepan-cies in the common
tests consisted of one false-
VOL. 15, 1982
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422 ESAIAS, RHODEN, AND SMITH
TABLE 2. Accuracy of identification by the Enteric-Tek system
with unknown enteric culturesOrganism No. correct/No. tested %
Correct
Proteus vulgarisProteus mirabilis (3)'Morganella morganii
(1)Providencia alcalifaciensProvidencia stuartii (3)Providencia
rettgeriEdwardsiella tarda (2)Salmonella enteritidisSalmonella,
atypical (5)Salmonella paratyphi ASalmonella typhi (1)Salmonella
cholerae-suisArizona hinshawii (1)Citrobacter
freundiiCitrobacterfreundii, atypical (2)Citrobacter
diversusCitrobacter amalonaticus (1)Shigella dysenteriaeShigella
flexneriShigella boydiiShigella sonneiEscherichia coliEscherichia
coli, H2S positiveEscherichia coli, atypical (10)Yersinia
enterocoliticaYersinia pseudotuberculosisKlebsiella pneumoniae
(1)Klebsiella oxytocaKlebsiella ozaenaeKlebsiella
rhinoschleromatisEnterobacter cloacaeEnterobacter
sakazakiiEnterobacter aerogenes (1)Enterobacter
gergoviaeEnterobacter agglomeransHafnia alveiSerratia
liquefaciensSerratia marcescensSerratia rubideaeSerratia
odorifera
9/99/910/1010/1012/128/8
12/129/95/53/43/44/4
11/119/90/210/1014/143/35/52/29/910/105/58/104/53/4
10/1010/106/96/6
10/102/2
10/105/5
10/1010/108/8
11/115/51/1
100.0100.0100.0100.0100.0100.0100.0100.0100.075.075.0
100.0100.0100.0
0.0100.0100.0100.0100.0100.0100.0100.0100.080.080.075.0100.0100.066.6100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
a Number in parentheses indicates the number of atypical strains
tested.
positive adonitol; one false-positive adonitol,lactose, and
sorbitol; and one false-positive ly-sine and false-negative
sorbitol strain. For threecultures of K. ozaenae, differentiation
requiredadditional conventional biochemical tests be-yond the two
tests, gas and motility, shown inthe code book. These cultures were
incorrectlyidentified by the Enteric-Tek system as Klebsiel-la
rhinoschleromatis, the first-choice identifica-tion. K. ozaenae was
given as the second choiceon the basis of a negative reaction for
gasproduction. The problem might be eliminated byincluding the
additional tests, esculin and gasfrom cellobiose, in their data
base. A positiveesculin reaction occurs in 75% of K.
ozaenaestrains, as compared with 15.4% of K. rhinosch-leromatis
strains. A positive reaction with gasfrom cellobiose has been shown
to occur in 70%of K. ozaenae strains, whereas all K. rhinosch-
leromatis strains show a negative gas reaction(11).
Five atypical strains with aberrant reactionpatterns were
misidentified. The organisms in-volved were two atypical E. coli
strains, whichwere indole and lactose negative; two atypicalC.
freundii strains (one H2S-negative strain andone H2S-negative
indole-positive strain); andone atypical ornithine-positive and
H2S-negativeS. typhi strain. The atypical S. typhi strain
wasincorrectly identified as S. enteritidis, as is sug-gested by
percentage charts supplied by themanufacturer (Flow Laboratories)
showing a100% negative ornithine reaction. These chartsalso show a
4% probability for E. coli strains tohave negative indole and
lactose reactions and a10% probability for H2S-negative and
indole-positive C. freundii strains. Misidentification ofthese
atypical E. coli and C. freundii strains by
J. CLIN. MICROBIOL.
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EVALUATION OF THE ENTERIC-TEK SYSTEM 423
TABLE 3. Misidentifications of unknown cultures by the
Enteric-Tek system
Reason No. % Misidentifications cu TotalculturesBiochemical
reaction discrepancy 3 27.3 1.0Atypical pattern 5 45.4
1.6Insufficient biochemical tests indicated 3 27.3 1.0Total 11
100.0 3.6
the Enteric-Tek system might be eliminated ifthese reactions
were included in the data base.Of the 11 misidentifications, 6 were
of typical
strains and 5 were of atypical strains (Table 4).Of the 11
misidentifications, 10 required supple-mental tests, including 5
serological confirma-tions for 1 S. paratyphi A and 1 atypical S.
typhistrain and Shigella serology for 1 Y. enterocoli-tica and 2
atypical E. coli strains, becauseShigella was listed as first,
second, and thirdchoices. The two Salmonella strains, identifiedas
S. enteritidis, did not meet expected specieslevel of
identification as claimed by the manu-facturer. However, had these
two Salmonellabeen identified only to genus, with
subsequentserology required, this would have increased theoverall
identification rate to 97.0%. Identifica-tions for the two atypical
E. coli strains werelisted as Shigella for all three choices for
onestrain and for the first three choices of the otherstrain, with
Y. enterocolitica given as a fourthchoice. Shigella serology was
required for theone misidentified Y. enterocolitica strain be-cause
Shigella was given as the third-choiceidentification.The Y.
enterocolitica strain, misidentified by
the Enteric-Tek system as K. rhinoschleromatis,presented an
interesting situation. The four iden-tification choices and their
probability percent-ages were listed in this order: K.
ozaenae(75.56%), K. rhinoschleromatis (21.19%), S.flexneri (3.06%),
and Y. enterocolitica (0.05%).S. flexneri could be eliminated as a
possibleidentification, on the basis of serology. We did
the three additional tests-gas, KCN, and raffi-nose-as suggested
by the manufacturer, and allthree gave a negative reaction. Since
K. ozaenaeshowed a greater probability for positive reac-tions in
all three tests, we eliminated this choiceas a possible
identification. On the basis of agreater probability percentage
given for K. rhin-oschleromatis (25.9%), we decided on thischoice
instead of Y. enterocolitica (0.05%) as theidentification. The
three negative test reactionsfavor the identification as Y.
enterocolitica rath-er than K. rhinoschleromatis. This
situationillustrates the potential for misidentifying anorganism if
the probability percentage given foreach choice identification is
the sole criterion.This example emphasizes the need to
considerequally all given information and use colonycharacteristics
before making an identification.Had the manufacturer suggested a
motility testat 25°C, a correct identification would have beenmade.
At the time our study was done, we wereunaware that the
manufacturer could provideidentification probability percentages
based onEnteric-Tek, plus additional tests.K. ozaenae presented the
greatest challenge
to the system, with three misidentificationscausing 27.3% of all
misidentifications. The re-maining erroneous identifications
involved twospecies, with two misidentifications each, andfour
species with only one misidentificationeach.The analysis of the
4,228 individual test com-
parisons revealed the Enteric-Tek System to bevery sensitive and
specific, showing high test
TABLE 4. Identification errors made by the Enteric-Tek
systemOrganism Enteric-Tek identification Reason for
misidentification
S. paratyphi A (1)' S. enteritidis Lysine positive and sorbitol
positivebS. typhi (1)C S. enteritidis Ornithine positive and H2S
negativeC. freundii (2)c E. agglomerans H2S negative
E. coli H2S negative and indole positiveE. coli (2)c Y.
enterocolitica Indole negative and lactose negative
Unidentified Indole negative and lactose negativeY.
enterocolitica (1) K. rhinoschleromatis Adonitol positive bY.
pseudotuberculosis (1) K. rhinoschleromatis Adonitol, lactose, and
sorbitol positivebK. ozaenae (3) K. rhinoschleromatis (3) Gas and
motilityd
a Number in parentheses indicates the number of cultures.b
Biochemical reaction discrepancy.c Atypical strain.d Insufficient
biochemical test indicated.
VOL. 15, 1982
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424 ESAIAS, RHODEN, AND SMITH
correlations when compared with other rapididentification
systems. For comparison, an anal-ysis of the common test reactions
for severalrapid systems showed the following results forthe number
of tests with a 97% or better agree-ment, when each was compared
with the con-ventional counterpart: Enteric-Tek with 10 of
14(71.4%), Micro-ID with 6 of 11 (54.5%), API 20Ewith 6 of 15
(40%), and the Entero-Set 20 systemwith 6 of 16 tests (37.5%) (1,
2). The comparisonshowed that urease, citrate, arabinose,
adonitol,and malonate differed substantially in theiragreement
percentages. The urease test agree-ment was poorer in the
Enteric-Tek (83.4%) andEntero-Set 20 (95%) systems (1-4). The
highlysensitive urease test in the Enteric-Tek systemdid not cause
any misidentifications, whereasthe urease test in the Micro-ID
system hascaused misidentifications because of its lack
ofsensitivity and specificity (3). The Enteric-Teksystem performed
better in the citrate test with91.4% agreement, as compared with
the Entero-Set 20 (86%) and API 20E (83 to 86%) systems(1, 2). The
Entero-Set 20 showed poorer agree-ment for two additional tests,
adonitol (86%) andmalonate (89%), whereas the Enteric-Tek
andMicro-ID each gave similar agreement percent-ages for adonitol
(94%) and malonate (99%) (1,2, 4). A low agreement percentage for
the arabi-nose test (39 to 82%) in API 20E has beenreported, as
compared with 99 to 100% in Enter-ic-Tek, Micro-ID, and Entero-Set
20 (1, 2). Itmust be noted that such comparisons do haveinherent
weaknesses, as pointed out by Edberget al. (7).A rapid and accurate
identification system for
the Enterobacteriaceae is highly desirable in theclinical
laboratory. Such a system would provebeneficial in directing
antimicrobic therapy, aswell as increasing identification
capabilitieswithout additional demand on trained personnel.We found
the Enteric-Tek system to be accurateand easy to use. The
advantages included easyinoculation, minimal manipulation,
minimalgrowth for sufficient inoculum, useful listings
ofsupplemental tests and probability percentages,and easy reading
of color changes in the media.The major limitations involved
distinguishingbetween weakly positive and negative H2S reac-tions
and reading the indole test with weaklypositive strains. Although
the Enteric-Tekwheels are stackable, their size and shape
mayrequire more storage room, as compared withsome of the other
rapid kits.
Overall, we found that the Enteric-Tek systemprovided a highly
acceptable level of identifica-tion for the Enterobacteriaceae
within 18 to 24 hand served as an alternative procedure to
theconventional method. Because this study wasdesigned only to
determine the ability of the
Enteric-Tek system to identify the Enterobac-teriaceae,
additional testing will be necessary inevaluating its performance
in a clinical setting.Since atypical strains present the greatest
chal-lenge to the clinical laboratory worker, the needfor
subjective evaluation, particularly of colonymorphology, pigment,
and odor, remains essen-tial when an unusual organism is
encountered.
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2. Aldridge, K. E., and R. L. Hodges. 1981. Correlationstudies
of Entero-Set 20, API 20E, and conventionalmedia systems for
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3. Barry, A. L., and R. E. Badal. 1979. Rapid identificationof
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and A. G. Steigerwait. 1977. Taxonomic andnomenclature changes in
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J. A. Washington H. 1979. Evaluation of themodified Micro-ID system
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7. Edberg, S. C., B. Atkinson, C. Chambers, M. H. Moore,L.
Palumbo, C. F. Zorzon, and J. M. Singer. 1979. Clini-cal evaluation
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