Automated selection of microorganisms and identification using MALDI

Patent metadata

Field	Value
Publication number	US-9556495-B2
Application number	US-201314388430-A
Country	US
Kind code	B2
Filing date	Apr 2, 2013
Priority date	Mar 30, 2012
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

A method and apparatus for locating and selecting a colony of microorganisms on a culture dish and identifying microorganisms in said selected colony using MALDI. The method comprises the automated steps of locating and selecting a colony of microorganisms on a culture dish; obtaining a sample of said selected colony of microorganisms; depositing at least some of said sample of said selected colony of microorganisms on a target plate; and transferring said target plate with said sample in an apparatus for performing MALDI for identification of said sample of said selected colony of microorganisms. A sample of a colony of microorganisms is automatically deposited on a depositing spot such that the sample covers at most approximately half of said one of the depositing spots of the target plate. A suspension of a sample of microorganisms is automatically prepared by automatically picking the sample with a picking tool and submerging the picking tool with said sample in a suspension, after which the picking tool is vibrated in vertical sense only to release the sample from the picking tool.

First claim

The invention claimed is:

1. A method for locating and selecting a colony of microorganisms on a culture dish and identifying microorganisms in said selected colony using MALDI, wherein said method comprises the automated steps of:
locating and selecting a colony of microorganisms on a culture dish;
obtaining a sample of said selected colony of microorganisms;
depositing at least some of said sample of said selected colony of microorganisms on a target plate; and
wherein the step of depositing at least some of said sample of said selected colony of microorganisms on a target plate is performed by the automated steps of:
transferring said obtained sample into a suspension tube containing an amount of a suspension medium;
preparing a common sample suspension by transferring at least a portion of said obtained sample into said suspension medium;
obtaining a first drop of said common sample suspension; and
transferring said drop of common sample suspension onto said target plate.
transferring said target plate with said sample in an apparatus for performing MALDI for identification of said sample of said selected colony of microorganisms; and

wherein the method further comprises the automated steps of:
obtaining a second drop of said common sample suspension;
depositing said second drop of common sample suspension on a test culture dish; and
transferring said test culture dish to an apparatus for performing a susceptibility test or another additional analysis,

wherein the method further comprises providing an automatic suspension medium dispenser that automatically dispenses the suspension medium in the suspension tube wherein the a common sample suspension is prepared by:
providing a turbidity meter for performing measurements of the turbidity of a suspension medium contained in a suspension tube;
providing a final measurement indicative of the measured turbidity;
providing a controller communicatively connected to the automatic suspension medium dispenser and the turbidity meter for automatically controlling the operation of the automatic suspension medium dispenser and the operation of the turbidity meter respectively;

wherein said controller compares the final measurement value to a first threshold value, and, if the final measurement is above a first threshold value, the controller causes the automatic suspension medium dispenser to supply an additional amount of suspension medium into the suspension tube; and, if the final measurement is identical to or below the first threshold value and identical to or above a second threshold value, said first threshold value being equal to or greater than the second threshold value, the controller communicates that the suspension can be removed for further processing.

2. A method according to claim 1 , wherein the method further comprises the automated step of overlaying a drop of a MALDI matrix solution on said drop of common sample suspension deposited on the target plate.

3. A method according to claim 2 , wherein said drop of common sample suspension deposited on the target plate is allowed to dry before said drop of MALDI matrix solution is overlaid.

4. A method according to claim 1 , further comprising the automated steps of:
providing a first picking tool and providing a positioning device with a picking tool holder for holding a picking tool, said positioning device being arranged for positioning a picking tool in a starting position above the obtained location of the selected colony of microorganisms on the culture dish and for automatically lowering and raising a picking tool towards and away from the culture dish and for positioning a picking tool in a transfer position, respectively;
positioning said first picking tool in said picking tool holder of the positioning device;
by said positioning device positioning the first picking tool in the starting position above the obtained location of the selected colony of microorganisms on the culture dish, automatically lowering the first picking tool towards the culture dish into contact with the microorganism to pick up a sample of said microorganism, automatically raising the first picking tool with said sample of the microorganism away from the culture dish to the transfer position;
providing a suspension tube holder for holding a suspension tube;
positioning a suspension tube in the suspension tube holder;
providing a transferring device for automatically transferring a picking tool from the transfer position of the positioning device to a position above a suspension tube held in the suspension tube holder, and for lowering and raising a picking tool into and away from a suspension medium contained in a suspension tube, and for positioning a picking tool in a waiting position above a suspension tube held in the suspension tube holder, respectively;
providing a controller communicatively connected to the positioning device, the transferring device, for automatically controlling the movement of the positioning device and the movement of the transferring device, and the operation of the automatic suspension medium dispenser and the operation of the turbidity meter.

5. A method according to claim 4 , wherein the method comprises providing an automatic culture dish positioning and removing device for automatically positioning and removing a culture dish comprising said microorganism on and from the stage, respectively, the step of arranging the controller such that it is communicatively connected to the automatic culture dish positioning and removing device for controlling the operation of the automatic culture dish positioning and removing device, wherein the step of positioning a culture dish comprising said microorganism on the stage is performed automatically under control of the controller.

6. A method according to claim 5 , wherein the controller is arranged such that a culture dish is allowed to be automatically removed from the stage by the automatic culture dish positioning and removing device only after the signal that the suspension tube with the suspension can be removed from the suspension tube holder for further processing has been provided.

7. A method according to claim 4 , wherein the method comprises providing an automatic suspension tube positioning and removing device for automatically positioning and removing a suspension tube in and from the suspension tube holder, respectively, the step of arranging the controller such that it is communicatively connected to the automatic suspension tube positioning and removing device for controlling the operation of the automatic suspension tube positioning and removing device, wherein the step of positioning a suspension tube in the suspension tube holder is performed automatically under control of the controller.

8. A method according to claim 7 , wherein the controller is arranged such that a suspension tube holder is automatically removed from the suspension tube holder by the automatic suspension tube positioning and removing device only after the signal that the suspension tube with the suspension can be removed from the suspension tube holder for further processing has been provided.

9. A method according to claim 4 , wherein the method comprises the step of providing an identifying mark on the suspension tube, and the step of storing the identifying mark of said suspension tube together with the properties of the suspension with a link to the identity of the culture dish from which the selected colony of microorganisms was obtained in the memory of said central control computer.

10. A method for automatic preparing a suspension of a sample of microorganisms according to claim 4 , wherein the method comprises providing an

Assignees

• Bd Kiestra Bv

Inventors

• Botma Jetze
• Kleefstra Martijn
• Van Der Zee Tino Walter

Classifications

• C12M33/04

  by injection or suction, e.g. using pipettes, syringes, needles (pipettes in general B01L3/02) · CPC title

• G01N35/10 Primary

  Devices for transferring samples {or any liquids} to, in, or from, the analysis apparatus, e.g. suction devices, injection devices {(G01N35/0099 takes precedence)} · CPC title

• G01N2035/1032

  Dilution or aliquotting · CPC title

• C12M41/48

  Automatic or computerized control (automatic analysis G01N35/00) · CPC title

• G01N35/00029 Primary

  provided with flat sample substrates, e.g. slides (G01N35/028 takes precedence) · CPC title