Fast detection of the presence of a target microbe in a liquid sample

• US 10,190,147 B1
• Filed: 06/30/2016
• Issued: 01/29/2019
• Est. Priority Date: 01/17/2012
• Status: Active Grant

• Current Assignee: Elemental Scientific Incorporated
• Original Assignee: Elemental Scientific Incorporated
• Inventors: Wiederin, Daniel R.
• Primary Examiner(s): Bowers, Nathan A
• Application Number:
  US15/198,024
• Time in Patent Office: 943 Days
• CPC Class Codes: C12Q 1/04 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 Class Codes: C12Q 1/10 Enterobacteria
• CPC Class Codes: G01N 2021/7786 Fluorescence
• CPC Class Codes: G01N 21/253 for batch operation, i.e. multisample apparatus analytical automats G01N35/00
• CPC Class Codes: G01N 21/77 by observing the effect on a chemical indicator
• CPC Class Codes: G01N 35/00 Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor

Abstract

A system is provided that includes a tray having a number of compartments for holding liquid samples and partitioning the liquid samples from one another. The liquid samples are prepared by adding an indicator configured to produce a characteristic change in light from the liquid samples when a target microbe metabolizes the indicator while the liquid samples are incubated. The system also includes a light sensor for sensing light from the liquid samples held in the tray while the plurality of liquid samples is incubated. The system further includes a processor coupled with the light sensor and configured to analyze the light from the liquid samples while the liquid samples are incubated to detect the characteristic change in light from one or more of the liquid samples if the target microbe is present in the liquid samples.

Claims

1. A method comprising:

holding a plurality of liquid samples prepared by adding an indicator configured to produce a characteristic change in light from the plurality of liquid samples when a target microbe metabolizes the indicator while the plurality of liquid samples is incubated, the plurality of liquid samples being held in a tray including a plurality of compartments partitioned one from another;

automatically sensing light from each of the plurality of liquid samples while the plurality of liquid samples is incubated; and

detecting the characteristic change in light from each of the plurality of liquid samples based on the sensed light from each of the plurality of liquid samples;

detecting a number of occurrences of the characteristic change in light from the plurality of liquid samples as the plurality of liquid samples is incubated;

determining whether the detected number of occurrences of the characteristic change in light exceeds a threshold number of occurrences of the characteristic change in light, the threshold number of occurrences of the characteristic change in light corresponding to a concentration of the target microbe within the liquid samples indicative of the presence of the target microbe; and

providing an indication that a presence of the target microbe has been detected based upon the determination,

wherein at an intermediate time interval prior to the end of the incubation period, the threshold number of occurrences of the characteristic change in light is a first threshold number associated with the intermediate time interval and the concentration of the target microbe is indicated by a number of occurrences of the characteristic change in light from a predetermined number of the plurality of liquid samples that exceeds the first threshold number,

wherein at the end of the incubation period, the threshold number of occurrences of the characteristic change in light is a second threshold associated with the entire incubation period and the concentration of the target microbe is indicated by a number of occurrences of the characteristic change in light from the plurality of liquid samples that exceeds the second threshold number.

2. The method as recited in claim 1, further comprising preparing the plurality of liquid samples by adding a growth accelerant for accelerating growth of the target microbe.

3. The method as recited in claim 1, further comprising identifying the presence of the target microbe in the plurality of liquid samples as soon as the characteristic change in light is detected for a pre-specified number of the plurality of liquid samples.

4. The method as recited in claim 1, wherein the target microbe comprises Escherichia coli (E. coli).

5. The method as recited in claim 1, further comprising receiving a liquid sample and portioning the liquid sample into the plurality of liquid samples.

6. The method as recited in claim 1, further comprising illuminating the plurality of liquid samples.

7. The method as recited in claim 1, wherein illuminating the plurality of liquid samples comprises illuminating one of the plurality of liquid samples at a time.

8. The method as recited in claim 1, wherein automatically sensing light from the plurality of liquid samples comprises sensing light from one of the plurality of liquid samples at a time.