Method for detecting Escherichia coli in a sample

Patent metadata

Field	Value
Publication number	US-10023898-B2
Application number	US-201715628750-A
Country	US
Kind code	B2
Filing date	Jun 21, 2017
Priority date	Dec 30, 2010
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

A method of detecting Listeria monocytogenes. The method comprises providing a culture device with a selective culture medium and a detection article comprising a first indicator system. The selective culture medium facilitates the growth of Listeria microorganisms. When a Listeria microorganism is detected in a sample contacted with the culture medium, the detection article is contacted with the culture medium to detect Listeria monocytogenes.

First claim

The invention claimed is:

1. A method for detecting an Escherichia coli microorganism in a sample, the method comprising:
providing:
a culture device including a culture medium comprising ingredients selected to facilitate growth of an Enterobacteriaceae microorganism;
a detection article comprising a first indicator system, the first indicator system selected to detect Escherichia coli;
wherein the Escherichia coli microorganism is detected by its ability to convert the first indicator system from a first state to a second state;

a second indicator system selected to detect the Enterobacteriaceae microorganism; and
a sample;

inoculating the culture device with the sample;
placing the second indicator system in fluid communication with the culture medium;
incubating the inoculated culture device for a period of time sufficient to permit growth of the Enterobacteriaceae microorganism, if the Enterobacteriaceae microorganism is present in the sample;
observing the culture device to detect at least one Enterobacteriaceae microorganism;
wherein observing the culture device for an indication of the presence of the at least one Enterobacteriaceae microorganism comprises detecting a conversion of the second indicator system from a first state to a second state;

contacting the culture medium of the incubated culture device with the first indicator system of the detection article only if the at least one Enterobacteriaceae microorganism is detected; and
observing the article-contacted culture device to detect a conversion of the first indicator system from a first state to a second state;
wherein the first and second indicator systems are distinct;
wherein conversion of the first indicator system from the first state to the second state by the at least one Enterobacteriaceae microorganism indicates the at least one Enterobacteriaceae microorganism is Escherichia coli.

2. The method of claim 1 , wherein providing the culture device further comprises providing a culture device that comprises a hydrogel or a dry, cold-water-soluble gelling agent.

3. The method of claim 1 , wherein the first indicator system comprises a reagent to detect β-glucuronidase enzyme activity.

4. The method of claim 1 , wherein observing the culture device or the article-contacted culture device comprises observing the culture device visually.

5. The method of claim 1 , wherein observing the culture device or the article-contacted culture device comprises observing the culture device using an imaging device.

6. The method of claim 1 , further comprising enumerating Escherichia coli colony-forming units in the culture device.

7. The method of claim 1 , wherein contacting the culture medium with the detection article further comprises contacting the culture medium with the detection article at a predetermined temperature.

8. A method for detecting an Escherichia coli microorganism in a sample, the method comprising:
providing:
a culture device including a culture medium comprising ingredients selected to facilitate growth of a coliform microorganism;
a detection article comprising a first indicator system, the first indicator system selected to detect Escherichia coli;
wherein the Escherichia coli microorganism is detected by its ability to convert the first indicator system from a first state to a second state;

a second indicator system selected to detect the coliform microorganism; and
a sample;

inoculating the culture device with the sample;
placing the second indicator system in fluid communication with the culture medium;
incubating the inoculated culture device for a period of time sufficient to permit growth of the coliform microorganism, if the coliform microorganism is present in the sample;
observing the culture device to detect at least one coliform microorganism;
wherein observing the culture device for an indication of the presence of the at least one coliform microorganism comprises detecting a conversion of the second indicator system from a first state to a second state;

contacting the culture medium of the incubated culture device with the first indicator system of the detection article only if the at least one coliform microorganism is detected; and
observing the article-contacted culture device to detect a conversion of the first indicator system from a first state to a second state;
wherein the first and second indicator systems are distinct;
wherein conversion of the first indicator system from the first state to the second state by the at least one coliform microorganism indicates the at least one coliform microorganism is Escherichia coli.

9. The method of claim 8 , wherein providing the culture device further comprises providing a culture device that comprises a hydrogel or a dry, cold-water-soluble gelling agent.

10. The method of claim 8 , wherein the first indicator system comprises a reagent to detect β-glucuronidase enzyme activity.

11. The method of claim 8 , wherein observing the culture device or the article-contacted culture device comprises observing the culture device visually.

12. The method of claim 8 , wherein observing the culture device or the article-contacted culture device comprises observing the culture device using an imaging device.

13. The method of claim 8 , further comprising enumerating Escherichia coli colony-forming units in the culture device.

14. The method of claim 8 , wherein contacting the culture medium with the detection article further comprises contacting the culture medium with the detection article at a predetermined temperature.

15. A method for detecting an Escherichia coli microorganism in a sample, the method comprising: inoculating a culture device comprising a culture medium with a sample to form an inoculated culture device, wherein
the culture medium comprises ingredients selected to facilitate growth of an Enterobacteriaceae microorganism;
placing a second indicator system in fluid communication with the culture medium;
incubating the inoculated culture device for a period of time sufficient to permit growth of the Enterobacteriaceae microorganism, if the Enterobacteriaceae microorganism is present in the sample;
observing the culture device to detect at least one Enterobacteriaceae microorganism;
wherein observing the culture device for an indication of the presence of the at least one Enterobacteriaceae microorganism comprises detecting a conversion of the second indicator system from a first state to a second state;
contacting the culture medium of the incubated culture device with a first indicator system of the detection article only if the at least one Enterobacteriaceae microorganism is detected; and
observing the incubated culture device after the incubated culture device is contacted with the culture medium to detect whether the first indicator system is converted from a first state to a second state;
wherein the first and second indicator systems are distinct; and
wherein conversion of the first indicator system from the first state to the second state by the at least one Enterobacteriaceae microorganism indicates the at least one Enterobacteriaceae microorganism is Escherichia coli.

16. The method of claim 15 , wherein the culture device comprises a hydrogel or a dry, cold-water-soluble gelling agent.

17. The method of claim 15 , wherein the first indicator system comprises a reagent to detect β-glucuronidase enzyme activity.

18. The method of claim 15 , wherein at least one of observing the culture device to detect at least o

Assignees

• 3M Innovative Properties Co

Inventors

• Moriyama Takatoshi
• Mach Patrick A
• Kitahara Akio
• Lubrant Henry J

Classifications

• C12Q1/34

  involving hydrolase · CPC title

• C12Q1/10

  Enterobacteria · CPC title

• C12Q1/04 Primary

  Determining presence or kind of microorganism; Use of selective media for testing antibiotics or bacteriocides; Compositions containing a chemical indicator therefor {(C12Q1/6897 takes precedence)} · CPC title

• C12Q1/44

  involving esterase · CPC title

• C12Q1/22

  Testing for sterility conditions · CPC title