Unit and method for preparing a sample for the microbiological analysis of a liquid

• US 20100012589A1
• Filed: 07/09/2009
• Published: 01/21/2010
• Est. Priority Date: 07/16/2008
• Status: Active Grant

• Current Assignee: EMD Millipore Corporation (Merck & Co., Inc.)
• Original Assignee: EMD Millipore Corporation (Merck & Co., Inc.)
• Inventors: Waiche, Gaël, Ribault, Sebastien, Simon, Emmanuelle, Felden, Luc
• Granted Patent: US 8,133,457 B2
• Time in Patent Office: Days
• US Class Current: 210/650
• CPC Class Codes: B01L 2200/026 Fluid interfacing between devices or objects, e.g. connectors, inlet details
• CPC Class Codes: B01L 2300/049 Valves integrated in closure
• CPC Class Codes: B01L 2300/0681 Filter
• CPC Class Codes: B01L 2400/0409 centrifugal forces
• CPC Class Codes: B01L 2400/0622 distribution valves, valves having multiple inlets and/or outlets, e.g. metering valves, multi-way valves
• CPC Class Codes: B01L 2400/0644 rotary valves
• CPC Class Codes: B01L 3/502 with fluid transport, e.g. in multi-compartment structures centrifugal-type cuvettes G01N21/07; analysis by separation into components G01N30/00; automatic analysers G01N35/00
• CPC Class Codes: B01L 3/5021 Test tubes specially adapted for centrifugation purposes centrifuges B04B5/04
• CPC Class Codes: G01N 1/2813 Producing thin layers of samples on a substrate, e.g. smearing, spinning-on G01N1/30 takes precedence
• CPC Class Codes: G01N 1/4077 by other techniques involving separation of suspended solids
• CPC Class Codes: G01N 2001/4088 filtration
• CPC Class Codes: Y10T 436/255 including use of a solid sorbent, semipermeable membrane, or liquid extraction
• CPC Class Codes: Y10T 436/2575 Volumetric liquid transfer

Abstract

The unit comprises a filter membrane (6) filter module (2) and a collection module (3) for each liquid coming from said filter module (2), with said filter module (2) comprising an inlet compartment as well as an evacuation compartment for the liquids, the filter (2) and collection (3) modules being rotatably mounted relative to each other.

The method comprises the step of obtaining such a unit (1), of disposing the filter (2) and collection (3) modules in a first position, of passing a liquid from the filter module (2) to attain the collection module (3), of disposing the filter (2) and collection (3) modules relative to each other in a second position, and the step of passing another liquid from the filter module (2) to attain the collection module (3).

Claims

1. A unit for preparing a sample for the microbiological analysis of a predetermined volume of liquid that may contain microorganisms comprising a filter membrane filter module and a collection module for each liquid coming from said filter module, with said filter module comprising an inlet compartment for inletting said predetermined volume by an inlet opening of said filter module, said inlet compartment being adapted to contain the whole of said predetermined volume, as well as an evacuation compartment for evacuating said predetermined volume by an evacuation opening of said filter module to said collection module, said evacuation compartment being separated from said inlet compartment by said membrane, the filter and collection modules being rotatably mounted relative to each other, and having, relative to each other, a first relative predetermined position, in which said evacuation opening of said filter module is in register with a first opening of said collection module and a second relative predetermined position different from said first position, in which said evacuation opening of said filter module is in register with a second opening of said collection module characterized in that said inlet and evacuation compartments are on opposite sides from each other relative to said filter membrane with said inlet compartment being arranged such that, when said predetermined volume is in said inlet compartment the liquid is in contact with the filter membrane over at least the majority of its surface.

2. A unit according to claim 1, wherein in said first predetermined position, said second opening is obturated and in that, in said second predetermined position, said first opening is obturated.

3. A unit according to claim 1, wherein said filter and collection modules also have another predetermined position relative to each other, termed obturating position, different from the first and second positions, in which said evacuation opening is obturated.

4. A unit according to claim 3, wherein in said obturating position, said first and second openings are also obturated.

5. A unit according to claim 1, wherein said filter and collection modules also have another predetermined position relative to each other, termed take-off position, different from the first and second positions, in which said second opening is in register with a take-off opening that said unit comprises.

6. A unit according to claim 1, wherein said filter module comprises a body within which is fixed said filter membrane as well as a separation membrane that is situated between said inlet opening and said filter membrane, said separation membrane having a pore diameter greater than the pore diameter of said filter membrane.

7. A unit according to claim 6, wherein said separation membrane is fixed to a first portion of said body and said filter membrane is fixed to a second portion of said body, with said first and second portions being adapted to be nested one inside the other and welded together.

8. A unit according to claim 6, wherein said filter module comprises another membrane juxtaposed against said separation membrane, on the opposite side of the separation membrane to the filter membrane, other membrane having a greater pore diameter than the pore diameter of said separation membrane.

9. A unit according to claim 6, wherein the pore diameter of said separation membrane is greater than 1 μ

m.

10. A unit according to claim 6, wherein the pore diameter of said filter membrane is less than 1 μ

m.

11. A unit according to claim 6, wherein said filter module comprises another opening formed in said body and giving access to a compartment of said body situated between said separation and filter membranes.

12. A unit according to claim 11, wherein said opening is situated at the end of a channel formed in said body.

13. A unit according to claim 12, wherein said opening of said channel is substantially situated at the same level as the inlet opening of the liquid that may contain microorganisms.

14. A unit according to claim 1, wherein said collection module comprises a disc of which the perimeter is adapted to be received in an annular groove that said filter module comprises.

15. A unit according to claim 1, wherein said filter module comprises indexing means and said collection module comprises complementary indexing means for each predetermined position of the filter module relative to the collection module.

16. A unit according to claim 15, wherein said indexing means comprise a fin and in that said complementary indexing means comprise ribs each having a cut-out adapted to receive said fin.

17. A unit according to claim 1, wherein said first opening (95) of the collection module issues to a reservoir (52) that said collection module comprises.

18. A unit according to claim 17, wherein the collection module comprises a vent adapted allow air to pass into said reservoir.

19. A unit according to claim 17, wherein said reservoir has a crescent-shaped cross-section.

20. A unit according to claim 1, wherein said second opening of the collection module issues to a reservoir that said collection module comprises.

21. A unit according to claim 20, wherein said reservoir has latching means adapted to cooperate with complementary latching means that said collection module comprises.

22. A unit according to claim 1, wherein said collection module comprises a seal in which are formed two ducts, each respectively issuing, on the same side as the filter module, by said first opening and by said second opening.

23. A unit according to claim 22, wherein said seal has a bean-shaped cross-section.

24. A unit according to claim 1, wherein said filter module comprises a vent adapted to allow air to pass into said inlet compartment.

25. A method of preparing a sample for the microbiological analysis of a predetermined volume of liquid that may contain microorganisms, comprising:

the step of obtaining a preparation unit according to claim 1;

the step of disposing the filter module and collection module of that unit relative to each other in said first predetermined position;

the step of passing said predetermined volume of liquid that may contain microorganisms from the filter module to attain the collection module through said evacuation opening of the filter module and through said first opening of the collection module;

the step of disposing the filter module and collection module relative to each other in said second predetermined position; and

the step of passing a predetermined volume of another liquid from the filter module to attain the collection module through said evacuation opening of the filter module and through said second opening of the collection module.

26. The method according to claim 25, wherein said steps of passing said predetermined volumes from the filter module to attain the collection module are implemented by centrifuging.

27. The method according to claim 25, further comprising, prior to said step of passing said predetermined volume of said other liquid through said evacuation opening of the filter module and through said second opening of the collection module, the step of selecting as other liquid, a liquid adapted to cause the lysis of the microorganisms retained on said filter membrane, the step of depositing on said filter membrane said predetermined volume of said other liquid, and then the step of leaving said other liquid to act on said microorganisms for a predetermined time.

28. A The method according to claim 27, further comprising, subsequent to the step of passing said predetermined volume of said other liquid through said evacuation opening of the filter module and through said second opening of the collection module, the step of retrieving said predetermined volume of said other liquid for analysis.