Enterohemorrhagic Escherichia coli (E. coli), which has been reported in association with extensive food poisoning or deaths, induces symptoms by producing verotoxins (VTs). The verotoxins are broadly classified into verotoxin type 1 (VT1) and verotoxin type 2 (VT2), which are known to have very strong toxicity. In Japan, a number of serotypes have been detected such as O157 and O26) . For these serotypes, test methods2) have already been provided through notification from the reguratory authority. For other E. coli. serotypes, examination of verotoxins in food is effective in preventing enterohemorrhagic food poisoning. Furthermore, a verotoxin test should be performed if enterohemorrhagic E. coli is detected because verotoxin production is used to confirm enterohemorrhagic E. coli. This product is a kit for detecting verotoxin using immunochromatography. With this kit, simple tests can be conducted rapidly to differentiate VT1 and VT2.
1) Detection of verotoxin in foods
2) Examination of VT1 and VT2 production from isolated enterohemorrhagic E. coli.
# The simple one-step operation of the kit.
# The test gives rapid results.
# There is no need for special test equipment.
1) Sensitivity test
The results of tests conducted in accordance with instructions for the preparation of the sample solution and the operating procedures for testing described in this manual will be positive when the concentration of both VT1 and VT2 is more than 2.5 ng/mL.
2) Reproducibility test
When VT1 and/or VT2 sample solution and negative sample solutions (mEC broth with novobiocin and CAYE medium) were simultaneously tested three times each, all positive sample solutions exhibited positive results and all negative sample solutions showed negative results.
3) Minimum detection sensitivity
The results of testing of purified VT1 and VT2 confirmed that the minimum detection sensitivity is 2.5 ng/mL for both VT1 and VT2.
(1) Cross-reactivity with the following bacterial strains has not been observed.
|Strains||ID of standard strains||Results|
|Escherichia coli||ATCC 43888 922, 11775||-|
|Escherichia hermanii||JCM 1473||-|
|Citrobacter freundii||ATCC 8090||-|
|Enterobacter aerogenes||ATCC 13048||-|
|Enterobacter cloacae||ATCC13047, 49141||-|
|Klebsiella oxytoca||ATCC 8724||-|
|Serratia liquefaciens||ATCC 27592||-|
|Serratia marcescens||ATCC 8100||-|
|Serratia odorifera||ATCC 33077||-|
|Proteus vulgaris||ATCC 6380||-|
|Pseudomonas aeruginosa||ATCC 9027||-|
1) Part names
a. Sample solution drop section (Be careful not to touch this section with your finger.))
b. Reagent-containing section
c. Detecting section (Be careful not to scratch this section and touch this section with your finger)
d. Absorption pad
e. Measurement items listing position
f. Test line for detection VT1 appearance position (Approx.28mm from the sample solution drop section.)
g. Test line for detection VT2 appearance position (Approx.30mm from the sample solution drop section.)
h. Control line appearance position (Approx.40mm from the sample solution drop section)
2) Detection mechanism
When a sample solution is dropped onto the sample solution drop section, gold colloid-labeled anti-VT1 antibodies and gold colloid-labeled anti-VT2 antibodies (2) in the Reagent-containing section dissolve and form complexes with verotoxins (1). These complexes move to the detecting section by capillary attraction and are trapped by anti-VT1 or anti-VT2 antibodies (3) that is fixed in the test line appearance position. This results in the appearance of a reddish purple line of gold colloid. .This reddish purple line can be detected by visual inspection and used to judge the presence or absence of VT1 and VT2 in the sample solution. The excess gold-labeled antibodies, regardless of the presence or absence of verotoxin in the sample solution, travel further through the detecting section and are trapped by the anti-rabbit immunoglobulin antibodies (4) fixed at the control line appearance position, where they form a second reddish purple line. The presence of this line indicates that the sample solution has reached the detecting section.
NH Immunochromato VT1/2
To be used for research only. DO NOT use for human gene therapy or clinical diagnosis.