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QIAGEN
mericon
STEC Workflow Collaborative Study Protocol
May 2016
DRAFT
14
(
e
)
Interpretation of mericon E. coli O157 Screen Plus Results.-
(1) Results are interpreted
according to Table XXXX.XXD. The presence of DNA sequences due to the O157 serotype and/or the
virulence factors (
stx1/stx2
and
eae
) indicate the presumptive presence of pathogenic
E. coli
(STEC). (2)
No further action means the sample was negative for pathogenic
E. coli
and no additional testing is
needed. (3) Additional testing required means the sample was presumptive positive for pathogenic
E.
coli
and should be tested by the
mericon
E. coli STEC O-Type assay for O157 and non-O157 STEC
serotypes. (4) An invalid IC with any target reactions negative indicates inhibition of the PCR reaction
and the sample should be diluted 1/10 with RNase-free water and retested.
Table XXXX.XXD.
mericon
E. coli O157 Screen Plus Results and Next Actions
Channel Outcome
Next Action
Orange
O157
Green
stx1
/
stx2
Crimson
eae
Yellow
IC
-
-
-
Valid
No further action
-
+
-
Valid
No further action
-
-
+
Valid
No further action
+
-
-
Valid
Additional testing required
-
+
+
Valid
Additional testing required
+
+
+
Valid
Additional testing required
-
-
-
Invalid
Dilute sample and repeat test
(
f
)
Interpretation of mericon E. coli STEC O-Type Results.-
(1) Results are interpreted according to
Table XXXX.XXE. The presence of DNA sequences due to the O157 serotype and/or one of the big six
non-O157 STEC serotypes indicates the presence of pathogenic
E. coli
(STEC). (2) No further action
means the sample was negative for pathogenic
E. coli
and no additional testing is needed. (3) Additional
testing required means the sample was positive for pathogenic
E. coli
and should be confirmed
according to the cultural confirmation procedures in K. (3) An invalid IC with either target reaction
negative indicates inhibition of the PCR reaction and the sample should be diluted 1/10 with RNase-free
water and retested.
Table XXXX.XXE.
mericon
E. coli STEC O-Type Results and Next Actions
Channel Outcome
Next action
Orange
O157:H7
Green
O26, O45, O103,
O111, O121,
O145
Yellow
IC
-
-
Valid
No further action
-
+
Valid
Additional testing required
+
-
Valid
Additional testing required
+
+
Valid
Additional testing required
-
-
Invalid
Dilute sample and repeat test
OMAMAN-36 B : Collaborative Study Protocol
For ERP Use Only
January 2017
AOAC Research Institute
Expert Review Panel Use Only