Testing for particulates
11680877 · 2023-06-20
Assignee
Inventors
- Lazar Fruchter (Efrat, IL)
- Arie Oscar Holtz (Jerusalem, IL)
- Robert Eric Levitz (Beit Shemesh, IL)
- Leah Forgosh (Jerusalem, IL)
- Boaz ARIELI (Mevaseret Tzion, IL)
Cpc classification
G01N1/4077
PHYSICS
B01L3/502
PERFORMING OPERATIONS; TRANSPORTING
International classification
C12N15/10
CHEMISTRY; METALLURGY
A61B10/00
HUMAN NECESSITIES
B01L3/00
PERFORMING OPERATIONS; TRANSPORTING
C12N15/115
CHEMISTRY; METALLURGY
Abstract
A testing device (20, 120, 220, 290, 320, 420, 520, 620, 720, 820, 1020, 1120) is provided for testing for the presence of particulate in a liquid (22). The testing device (20, 120, 220, 290, 320, 420, 520, 620, 720, 820, 1020, 1120) includes a liquid container (30, 730) for containing the liquid (22); a filter (32, 132, 732), disposed in or downstream of the liquid container (30, 730); a liquid-pressure source (34, 734), which is arranged to apply pressure to drive the liquid (22) contained in the liquid container (30, 730) through the filter (32, 132, 732); and a filter chamber (36, 136, 236, 336, 736) that is (a) disposed downstream of the liquid container (30, 730), (b) shaped so as to define an inlet (38, 138, 238, 738, 838), and (c) in fluid communication with the filter (32, 132, 732). Other embodiments are also described.
Claims
1. Apparatus comprising a testing device for testing for the presence of particulate in a liquid, the testing device comprising: a liquid container for containing the liquid, the liquid container shaped so as to define an upstream opening for receiving the liquid; a filter; a waste liquid receptacle; a liquid-pressure source, which (a) is arranged to apply pressure to drive the liquid contained in the liquid container through the filter and then into the waste liquid receptacle, and (b) comprises a plunger comprising a plunger head that is shaped so as to be insertable into the liquid container via the upstream opening of the liquid container; and a filter-receiving chamber that is (a) disposed downstream of the liquid container when the plunger head is within the liquid container, (b) shaped so as to define an inlet, and (c) in fluid communication with the filter, wherein the filter is removably disposed upstream of the filter-receiving chamber with the filter partially covering the inlet of the filter-receiving chamber, and arranged in the testing device to be movable at least partially into the filter-receiving chamber via the inlet after the liquid has been driven through the filter.
2. The apparatus according to claim 1, wherein the inlet of the filter-receiving chamber has an inlet area that is less than a greatest cross-sectional area of the filter-receiving chamber, the inlet area and the greatest cross-sectional area measured in respective planes parallel to each other.
3. The apparatus according to claim 1, wherein the filter-receiving chamber comprises one or more pressure-activated valves, not disposed at the inlet of the filter-receiving chamber.
4. The apparatus according to claim 1, wherein the apparatus further comprises an elongate member configured to push at least a portion of the filter into the filter-receiving chamber.
5. The apparatus according to claim 1, wherein the plunger head is configured to push at least a portion of the filter into the filter-receiving chamber.
6. The apparatus according to claim 1, wherein the filter-receiving chamber comprises one or more valves, not disposed at the inlet of the filter-receiving chamber.
7. The apparatus according to claim 6, wherein the one or more valves comprise one or more pressure-activated valves.
8. The apparatus according to claim 7, wherein the one or more valves comprise one or more non-pressure-activated valves.
9. The apparatus according to claim 1, wherein the liquid container is shaped so as to define one or more openings through a wall of the liquid container, wherein the one or more openings are downstream of the filter when the filter is removably disposed upstream of the filter-receiving chamber with the filter partially covering the inlet of the filter-receiving chamber, and wherein the filter-receiving chamber is not disposed so as to receive the liquid that is driven through the one or more openings, such that the one or more openings allow the liquid to pass, thereby drawing the liquid through the filter.
10. The apparatus according to claim 1, wherein the apparatus further comprises at least one container comprising an extraction reagent.
11. The apparatus according to claim 10, wherein the apparatus further comprises a test strip.
12. A method comprising: receiving liquid in a liquid container of a testing device, via an upstream opening of the liquid container; inserting a plunger head of a plunger into the liquid container via the upstream opening; applying pressure, by pushing the plunger within the liquid container, to drive the liquid through a filter of the testing device and then into a waste liquid receptacle of the testing device, while (a) the filter is removably disposed upstream of a filter-receiving chamber with the filter partially covering an inlet of the filter-receiving chamber, and (b) the filter-receiving chamber is disposed downstream of the liquid container in fluid communication with the filter; thereafter, moving at least a portion of the filter into the filter-receiving chamber via the inlet; thereafter, removing the entire filter from within the filter-receiving chamber and from the testing device; and thereafter, testing the filter, outside the testing device, for the presence of biological particulate trapped by the filter.
13. The method according to claim 12, wherein the liquid includes gargled fluid.
14. The method according to claim 12, wherein the liquid includes saliva not swabbed from a throat of a patient.
15. The method according to claim 12, wherein the liquid includes an incubated culture medium containing a biological sample.
16. The method according to claim 12, wherein the biological particulate is group A streptococcus bacteria.
17. The apparatus according to claim 1, wherein the filter-receiving chamber is nipple-shaped.
18. The apparatus according to claim 1, wherein the waste liquid receptacle is coupled to the liquid container downstream of the filter.
19. The apparatus according to claim 1, wherein the plunger is shaped so as to define the waste liquid receptacle.
20. The apparatus according to claim 19, wherein the plunger is shaped so as to define the filter-receiving chamber, and wherein the filter chamber is laterally surrounded by at least a portion of the waste liquid receptacle.
21. The apparatus according to claim 1, wherein the plunger is shaped so as to define the filter-receiving chamber.
22. The apparatus according to claim 21, wherein the apparatus further comprises an elongate member configured to move at least a portion of the filter into the filter-receiving chamber.
23. The method according to claim 12, wherein the plunger is shaped so as to define the filter-receiving chamber.
24. The method according to claim 12, wherein the waste liquid receptacle is coupled to the liquid container downstream of the filter.
25. The method according to claim 12, wherein the plunger is shaped so as to define the waste liquid receptacle.
26. The method according to claim 25, wherein the plunger is shaped so as to define the filter-receiving chamber, and wherein the filter-receiving chamber is laterally surrounded by at least a portion of the waste liquid receptacle.
27. The method according to claim 12, wherein moving the at least a portion of filter into the filter-receiving chamber comprises moving the at least a portion of filter into the filter-receiving chamber using an elongate member.
28. The method according to claim 12, wherein the liquid includes urine.
29. The method according to claim 12, wherein the liquid is selected from the group consisting of: blood, diluted stool, gastrointestinal (GI) fluid, and bronchoalveolar lavage fluid.
30. The method according to claim 12, wherein the filter-receiving chamber is laterally surrounded by at least a portion of the waste liquid receptacle.
31. The method according to claim 12, wherein the inlet of the filter-receiving chamber has an inlet area that equals no more than 40% of a filter surface area of an upstream side of the filter.
32. The method according to claim 23, wherein moving the at least a portion of filter into the filter-receiving chamber comprises moving the at least a portion of filter into the filter-receiving chamber using an elongate member.
33. The apparatus according to claim 1, wherein the filter-receiving chamber is laterally surrounded by at least a portion of the waste liquid receptacle.
34. The apparatus according to claim 1, wherein the inlet of the filter-receiving chamber has an inlet area that equals no more than 40% of a filter surface area of an upstream side of the filter.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF APPLICATIONS
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(30) Testing device 20 typically comprises: a liquid container 30 for containing liquid 22; typically, liquid container 30 has an internal volume of at least 0.5 ml (e.g., at least 1 ml, such as at least 5 ml), no more than 500 ml (e.g., no more than 70 ml), and/or between 0.5 ml (e.g., 1 ml or 5 ml) and 500 ml (e.g., 70 ml); a filter 32, disposed in or downstream of liquid container 30; and a liquid-pressure source 34, which is arranged to apply pressure to drive liquid 22 contained in liquid container 30 through filter 32.
(31) As used in the present application, including in the claims, “upstream” and “downstream” refer to the direction of fluid flow through testing device 20, and not the orientation of the device with respect to the Earth. For example, filter chamber 736, described hereinbelow with reference to
(32) Typically, liquid container 30 does not comprise a Luer lock or any other type of needle-coupling mechanism.
(33) Filter 32 comprises synthetic or natural materials formed, for example, as a matrix, membrane, fabric, beads, or other configuration. For example, the inventors have tested the following filters manufactured by Sterlitech (Washington, USA): Grade C glass microfiber filter media (Cat. No. C2500 & C3700) GC-50 glass fiber membrane filters (Cat. No. GC5037100) polyethersulfone (PES) membrane filters (Cat. No. PES0825100, PES0837100, PES1225100, PES1237100, PES06525100, PES4525100, PES4525100) polycarbonate membrane filters (Cat. No. PCT0613100, PCT2025100, PCT0625100, PCT1025100, PCT0825100) cellulose acetate membrane filters (Cat. No. CA0825100) polyester membrane filters (Cat. No. PET0125100, PET0825100)
(34) Typically, filter 32 is configured to trap at least 40% (such as at least 95%, e.g., at least 99%) of the particulate to be tested and allow passage of liquid 22. For example, for applications in which the particulate is group A streptococcus bacteria, the filter may be configured to trap at least 40% (such as at least 95%, e.g., at least 99%) of the group A streptococcus bacteria and allow passage of liquid 22. For some applications, filter 32 has a filter surface area of an upstream side of the filter equal to at least 0.3 cm2, no more than 100 cm2 (e.g., no more than 30 cm2), and/or between 0.3 cm2 and 100 cm2, such as between 0.3 and 30 cm2.
(35) For some applications, liquid-pressure source 34 comprises at least one of the following: a plunger 40, which comprises a plunger head 42 that is shaped so as to be insertable into liquid container 30 so as to form a movable seal with a wall of a plunger housing (optionally, all or a portion of liquid container 30 defines the wall of the plunger housing); a positive-pressure pump (e.g., a hydraulic pump, a syringe, or a motorized and/or electrical pump) disposed upstream of filter 32 (configuration not shown); optionally, for some application, the positive-pressure pump comprises a chamber with one or more flexible walls, the squeezing of which pumps air and/or liquid 22 itself out of the chamber; or a vacuum pump disposed downstream of filter 32 (and, if provided, of the one or more valves 60, described hereinbelow) (configuration not shown).
(36) For some applications, plunger 40 further comprises a plunger shaft, and plunger head 42 is disposed at a downstream end portion of the plunger shaft. Typically, but not necessarily, plunger 40 has one of the following configurations: the plunger head comprises a separate piece of material (e.g., comprising a polymer) that is coupled to the plunger shaft and is shaped so as to define the downstream surface of plunger head 42 and optionally a lateral sealing surface, or the distal surface of plunger head 42 is defined by the end of the plunger shaft, and, for example, a separate sealing ring (e.g., comprising a polymer) may be provided to provide a lateral sealing surface.
(37) For some applications, testing device 20 further comprises a waste liquid receptacle 46, which is coupled to liquid container 30 downstream of filter 32 (and, if provided, of the one or more valves 60, described hereinbelow). Liquid-pressure source 34 is arranged to apply pressure to drive liquid 22 contained in liquid container 30 through filter 32 and then into waste liquid receptacle 46.
(38) For some applications, testing device 20 further comprises a filter chamber 36 that is (a) disposed downstream of liquid container 30, (b) shaped so as to define an inlet 38, and (c) in fluid communication with filter 32. Filter chamber 36 is shaped such that when filter 32 is pushed into the filter chamber, such as described hereinbelow with reference to
(39) Optionally, filter chamber 36 is nipple-shaped. For some applications in which testing device 20 comprises waste liquid receptacle 46, filter chamber 36 is laterally surrounded by at least a portion of waste liquid receptacle 46, such as shown in
(40) For some applications, inlet 38 of filter chamber 36 has an inlet area that equals at least 4%, no more than 40%, and/or between 4% and 40% of a filter surface area of an upstream side of filter 32, such as between 10% and 20%. Alternatively or additionally, for some applications, filter chamber 36 has: an internal volume of at least 0.5 ml, no more than 12 ml (e.g., no more than 4 ml), and/or between 0.5 and 12 ml (such as between 0.5 and 4 ml), such as at least 1 ml (e.g., at least 2 ml), no more than 5 ml, and/or between 1 and 5 ml, such as between 2 and 5 ml, an internal surface area that equals at least 10%, no more than 150%, and/or between 10% and 150% of a filter surface area of an upstream side of filter 32, such as between 70% and 130%, an internal length L equal to between 0.5 and 10 cm, such as between 1.5 and 5 cm, an internal width W equal to between 0.3 and 3 cm, such as between 0.5 and 1.5 cm, an internal length L of at least 0.5 cm, no more than 10 cm (e.g., no more than 5 cm), and/or between 0.5 and 10 cm, such as between 0.5 cm and 5 cm, e.g., between 1 and 5 cm, and/or an internal length L equal to at least 50%, no more than 2000%, and/or between 50% and 2000% of a greatest internal width W of filter chamber 36, such as between 200% and 600%.
(41) For some applications, such as shown in
(42) For some applications, such as shown in
(43) For some applications, an elongate member 56 is provided that configured to push at least a portion of filter 32 into filter chamber 36. Optionally, elongate member 56 comprises a swab 58 at a distal end of the elongate member. In applications in which filter chamber 36 comprises one or more pressure-activated valves 50, inserting elongate member 56 into filter chamber may squeeze any liquid 22 remaining in filter chamber 36 through one or more pressure-activated valves 50 and out of filter chamber 36. For other applications in which liquid-pressure source 34 comprises plunger 40, plunger head 42 is configured to push at least a portion of filter 32 into filter chamber 36 (configuration not shown). In applications in which filter chamber 36 comprises one or more pressure-activated valves 50, inserting plunger head 42 into filter chamber may squeeze any liquid 22 remaining in filter chamber 36 through one or more pressure-activated valves 50 and out of filter chamber 36.
(44) Reference is still made to
(45) For some applications, the one or more valves 60 comprise one or more pressure-activated valves. For example, as mentioned above, filter chamber 36 may comprise one or more pressure-activated valves 50, not disposed at inlet 38. For example, the pressure-activated valves may be formed from slits or flaps in an elastic material (such as silicone), or may comprise any small valves known in the valve art. The one or more pressure-activated valves are configured to open at the higher pressure applied by liquid-pressure source 34, so as to allow liquid 22 to pass through filter 32, and to remain closed at the much lower pressure applied by at least one extraction reagent 86, as described hereinbelow with reference to
(46) Alternatively or additionally, for some applications, the one or more valves 60 comprise one or more non-pressure-activated valves, such as described hereinbelow with reference to
(47) For some applications, sterile packaging is provided, in which at least liquid container 30, filter chamber 36, the one or more valves 60, and/or filter 32 are removably disposed. The sterile packaging comprises one or more sterile packages; for example, each element may be removably disposed in a separate one of the packages, and/or more than one the elements may be disposed in a single one of the packages.
(48) For some applications, at least one container comprising the at least one extraction reagent 86 is provided. For example, the at least one extraction reagent 86 may comprise 2M sodium nitrite and/or 0.2M acetic acid, and/or a releasing agent, which, upon contacting a microorganism, releases an antigen from the microorganism. For applications in which more than one extraction reagent 86 is provided, and/or extraction reagent 86 comprises a plurality of substances, each of the extraction reagents 86 and/or substances may be provided in a separate container, and the extraction reagents 86 and/or substances are combined prior to (e.g., immediately prior to) performing the assay. Alternatively or additionally, for some applications, a test strip 88 is provided. Typically, test strip 88 is a lateral flow test strip, such as a lateral flow immunoassay (e.g., chromatographic immunoassay) test strip, as is known in the art. For example, test strip 88 may contain an antibody specific to strep A carbohydrate antigen, and the mixture migrates up the test strip and reacts with the antibody, thus generating a line on the test strip; the presence of this line indicates a positive test result. Alternatively or additionally, for some applications, a container is provided containing a solution for use in a detecting a pathogen.
(49) Reference is still made to
(50) Upstream component 70 typically comprises: a plunger housing 74, which is shaped so as to define an upstream opening 76 (labeled in
(51) Typically, plunger housing 74 does not comprise a Luer lock or any other type of needle-coupling mechanism.
(52) Downstream component 72 typically comprises: filter 32, which has a filter surface area if an upstream side of the filter equal to at least 80% of the area of downstream surface 80 of the downstream plunger head 42; waste liquid receptacle 46, disposed downstream of filter 32; and for applications in which it is provide, filter chamber 36.
(53) Testing device 20 is shaped so as to define liquid container 30 for containing liquid 22. Upstream component 70 and downstream component 72 are configured to be removably coupled together so as to form a liquid-impermeable seal, as shown in
(54) For some applications, such as shown in
(55) In general, in all of the configurations of testing devices described herein that comprise upstream and downstream components that are removably coupled together, the liquid container may be defined in part by the upstream component and in part by the downstream component. For example, a distal downstream wall of the liquid container that supports the filter may be defined by the downstream component, while the lateral wall of the liquid container may be defined by the upstream component or by the upstream and downstream components in combination.
(56) For some applications, such as shown in
(57) For some applications, an area of upstream opening 76 is greater than the area of downstream opening 78. For example, a diameter of upstream opening 76 may be at least 10% (e.g., 20%, such as 30%) greater than a diameter of downstream opening 78. For some of these applications, plunger housing 74 includes an upstream end portion 84 (labeled in
(58) Reference is still made to
(59) For applications in which one or more components of testing device 20 are removably disposed in sterile packing, the one or more components are removed from the sterile packaging.
(60) As shown in
(61) Alternatively, liquid 22 comprises saliva not swabbed from the throat of a patient (i.e., the saliva was collected without swabbing the patient's throat). (The distinction between “swab” as a verb and as a noun is noted. A “swab” (as a noun) may be used to obtain saliva without “swabbing” (as a verb) the patient's throat. For example, the patient may suck on a swab, or a swab may be dipped in a container into which gargle fluid or saliva has been placed.) By contrast, in commonly-practiced techniques for testing for strep, the tonsils are swabbed. Further alternatively, liquid 22 comprises liquid from a cultured medium containing a biological sample which had been incubated within the liquid container 30 or incubated separately from the device and then added to liquid container 30, for example for performing a backup test (e.g., a backup strep test) using rapid testing techniques, e.g., rapid strep testing techniques. As used in the present application, including in the claims, in the context of backup testing, “rapid” testing techniques (such as “rapid” strep testing techniques) refer to the type of test, rather than implying that the test is performed and provides results soon after the sample is obtained from the patient; indeed, for performing backup testing, the rapid testing techniques are typically performed well after the sample has been obtained from the patients, such as a number of hours thereafter, and typically include incubation of the sample.
(62) Liquid 22 (e.g., saliva) may be spit directly by the patient into liquid container 30 or transferred by a healthcare worker from another container into which the patient spit. Alternatively, in the case of saliva, the saliva may be collected from the patient's mouth by having the patient suck on a swab or other absorbent collecting element, such as flocked swabs or cotton rolls.
(63) For applications in which testing device 20 comprises plunger 40 and plunger housing 74, such as described above, liquid 22 is typically received in liquid container 30 before plunger 40 has been inserted into plunger housing 74 (or liquid container 30).
(64) As shown in
(65) As shown in
(66) As shown in
(67) As shown in
(68) Alternatively, for some applications, the entire filter 32 is removed from testing device 20 and tested, outside testing device 20, for the presence of the particulate. If such testing is a rapid strep test, the method may conclude with this test, and not continue with the performance of a test in testing device 20, as described hereinbelow with reference to
(69) As shown in
(70) For some applications, the testing is performed by: applying an extraction reagent 86 to filter 32, such as shown in
(71) Reference is still made to
(72) Reference is now made to
(73) Testing device 120 comprises a filter 132 that is disposed at least partially, e.g., entirely, within a filter chamber 136. By contrast, filter 32 of testing device 20 is removably disposed upstream of filter chamber 36 with filter 32 partially covering inlet 38. Other than this feature, filter 132 may have any of the features of filter 32 described hereinabove with reference to
(74) Filter chamber 136 may implement any of the features of filter chamber 36, described hereinabove with reference to
(75) Testing device 120 may be used as described hereinabove with reference to
(76) For some applications, filter 132 is disposed surrounding at least 270 degrees, typically 360 degrees, of a central longitudinal axis 124 of filter chamber 136, such that all or substantially all of liquid 22 that passes out of filter chamber 136 must pass through filter 132. For some applications, filter 132 covers all of the one or more pressure-activated valves 50. For some applications, filter 132 covers at least 80%, such as 100%, of the internal surface of filter chamber 136. For some applications, such as shown in
(77) Reference is now made to
(78) Testing device 220 further comprises a frangible seal 226 that removably blocks liquid flow into an inlet 238 of a filter chamber 236. For example, frangible seal 226 may comprise a pliable material (such as silicone) that is easily torn, such as shown in Option A in
(79) For some applications, filter chamber 236, before frangible seal 226 is broken, contains a material, such as a rapid test solution (e.g., a rapid strep test) in liquid or solid (e.g., powdered) form. This may simplify the use of the testing device because the material is not flushed during the application of pressure, and thus does not need to be added during use after applying the pressure.
(80) For some applications, testing device 20 further comprises a support for filter 32 (e.g., the configuration of frangible seal 226 shown in Option B in
(81) Reference is now made to
(82) Reference is now made to
(83) For applications in which the one or more valves 60 are provided, such as shown in
(84) The one or more second pressure relief valves 361 allow drainage of liquid 22 if excess pressure occurs in liquid container 30, such as if filter 32 becomes clogged during the application of pressure described hereinabove with reference to
(85) Reference is made to
(86) Reference is made to
(87) Reference is made to
(88) Reference is made to
(89) Testing device 620 comprises one or more unfiltered liquid receptacles 644 (e.g., vials). The one or more second pressure relief valves 361, 348 are in fluid communication with the one or more unfiltered liquid receptacles 644, such that when pressure is applied, as described hereinabove with reference to
(90) Reference is now made to
(91) Testing device 720 comprises a liquid-pressure source 734, which comprises a plunger 740, which comprises a plunger head 742 that is shaped so as to be insertable into a liquid container 730. Plunger 740 is shaped so as to define a waste liquid receptacle 746.
(92) Plunger 740 is also shaped so as to define a filter chamber 736. Filter chamber 736 typically does not comprise any pressure-activated valves 50. Testing device 720 further comprises a frangible seal 726 that removably blocks liquid flow into an inlet 738 of filter chamber 736. Frangible seal 726 may implement any of the features of frangible seal 226 described hereinabove with reference to
(93) For some applications, testing device 720 comprises a cap 792, which is removably coupled to a distal end of liquid container 730 (i.e., to the end opposite the end into which plunger 740 is inserted). A proximal wall 794 of cap 792 defines a distal wall of liquid container 730. For some applications, cap 792 is shaped so as to define an unfiltered liquid receptacle 744, and proximal wall 794 of cap 792 comprises one or more second pressure relief valves 761 that (a) are in fluid communication with unfiltered liquid receptacle 744 and, when cap 792 is coupled to liquid container 730, with liquid container 730, and (b) are disposed upstream of filter 732.
(94) Before use (e.g., during manufacture), cap 792 is removably coupled to liquid container 730, such as by twisting the cap onto liquid container 730, as shown in
(95) Liquid 22 (such as gargled fluid, saliva not swabbed from the throat of a patient, or an incubated culture medium containing a biological sample) is received in liquid container 730.
(96) As shown in
(97) As shown in
(98) As shown in
(99) As shown in
(100) The use of testing device 720 may continue as described hereinabove with reference to
(101) Reference is now made to
(102) Testing device 820 comprises waste liquid receptacle 46, which contains an antibacterial agent 824, such as a detergent, thiomersal, bleach, or iodine (I/KI) to kill any bacteria that passes through filter 32, to reduce the risk of contamination upon accidental exposure to the liquid in waste liquid receptacle 46.
(103) For some applications, an inlet 838 of a filter chamber 336 of testing device 820 has an inlet area that is less than a greatest cross-sectional area of filter chamber 336, the inlet area and the greatest cross-sectional area measured in respective planes parallel to each other. For example, the inlet area may be no more than 95%, such as no more than 90%, e.g., no more than 80% of the greatest cross-sectional area of filter chamber 336. Providing this narrowing of filter chamber 336 at inlet 838 may help retain filter 32 in filter chamber 336 during withdrawal of elongate member 56, as described hereinabove with reference to
(104) Reference is now made to
(105) The one or more valves 60 of testing device 920 comprise one or more non-pressure-activated valves 960. For example, the one or more non-pressure-activated valves 960 may be opened and closed by aligning and non-aligning, respectively, sets of openings in two discs 962A and 962B of the one or more non-pressure-activated valves 960, either manually or automatically by the testing device, such as described hereinbelow. Other manual and automated configurations will be readily apparent to those skilled in the art who have read the present application.
(106) During use, liquid 22 is received in a liquid container 930, as shown in
(107) Thereafter, as partially shown in
(108) As described hereinabove, for some applications, the testing devices described herein comprise a liquid-pressure source that is arranged to apply pressure to drive liquid contained in the liquid container through the filter and, optionally, then into the waste liquid receptacle. For some of these applications, the testing device is configured to automatically (typically, non-electrically) close one or more non-pressure-activated valves of the testing device after the plunger applies the pressure to drive the liquid contained in the liquid container through the filter and then through the one or more non-pressure-activated valves. For some of these applications, the testing device is configured such that motion of the plunger automatically (typically, non-electrically) closes the one or more non-pressure-activated valves after the plunger applies the pressure to drive the liquid contained in the liquid container through the filter and then through the one or more non-pressure-activated valves. Although the testing device is described in this and the following configurations as non-electrically closing the one or more non-pressure-activated valves, the testing device may alternatively electrically close the one or more non-pressure-activated valves, such as using a motor.
(109) Reference is now made to
(110) As shown in
(111) For some applications, plunger 1440 is shaped so as to define one or more plunger threads 1466, and an internal wall of liquid container 1430 is shaped so as to define one or more liquid-container threads 1468 that engage the one or more plunger threads 1466 such that rotation of plunger 1440 advances plunger 1440 in a downstream direction within liquid container 1430. Advancing plunger 1440 helps control the speed of the advancement and helps maintain steady advancement against pressure in liquid container 1430.
(112) For some applications, the one or more non-pressure-activated valves 1460 comprise two discs 1462A and 1462B, which are shaped so as to define respective sets of openings 1463A and 1463B, for example as described hereinabove with reference to
(113) For some applications, testing device 1420 comprises one or more reagent containers 1471, such as capsules, that contain one or more extraction reagents 86 (either the same type of extraction reagents or differing extraction reagents). Reagent containers 1471 are disposed at least partially in liquid container 1430, such that upon opening of the containers, such as by crushing, tearing, or breaking, extraction reagents 86 are released into liquid container 1430, typically near filter 32. For example, testing device 1420 may configured such that rotational motion of plunger 1440 automatically opens reagents containers 1471, such as by bringing one or more respective protrusions 1473 into contact with the reagent containers. For example, a fraction of the last turn (or the last turn), may automatically open reagents containers 1471. Typically, a fraction of last turn (may or may not include the last portion of the last turn) opens reagents containers 1471, and the fraction occurs after the fraction of the last turn that closes the one or more non-pressure-activated valves 1460, such that the one or more valves are closed before the reagents are released.
(114) Reference is made to
(115) In this portion of the method, the user typically receives testing device 1420 with the elements thereof removably coupled together, as shown in
(116) Reference is now made to
(117) Reference is now made to
(118) Reference is now made to
(119) Reference is now made to
(120) In these configurations, testing device 20 further comprises one or more heating elements 1000 that are configured to heat filter 32 and/or liquid 22 in liquid container 30 at a generally constant temperature, typically in the range of 20 and 50 degrees C., such as in the range of 30 to 40 degrees C. It is noted that the temperature is considered “generally constant” even if the temperature varies somewhat, such as because of cycling on and off of the one or more heating elements 1000.
(121) Heating elements 1000 may comprise, for example, electrical heating elements or chemical heating elements (e.g., a heating bag). For applications in which heating elements 1000 are electrical, they are coupled in electrical communication with a power supply 1002, such as an external power supply (e.g., the power grid) or an external or internal battery. For example, the coupling may be done using a conventional electrical plug or USB interface. For some applications, testing device comprises control circuitry 1004 and a heat sensor 1006 (e.g., a thermocouple or other thermostat), and control circuitry 1004 is configured to drive heating elements 1000 responsively to a temperature sensed using heat sensor 1006 in order to maintain the generally constant temperature mentioned above.
(122) For some applications, heating elements 1000 are disposed external to main body of testing device 20, such as supported by a stand 1001, such as shown in
(123) For other applications, such as shown in
(124) For still other applications, such as shown in
(125) For other applications, such as shown in
(126) For some applications, the one or more heating elements 1000 are configured to heat filter 32 and/or liquid 22 in liquid container 30 after most or nearly all (e.g., at least 90%) of liquid 22 has been driven out of liquid container 30 and the particulate has been trapped by filter 32, such as shown in
(127) For other applications, the one or more heating elements 1000 are configured to heat filter 32 and/or liquid 22 in liquid container 30 while most (e.g., at least 90%) or all of liquid 22 remains in liquid container 30 before being driven out of liquid container 30 and through filter 32, e.g., by pushing with plunger head 42, such as shown in
(128) Depending on the characteristics of the particular type of filter 32 used, the filter may be damaged (e.g., degraded) by immersion in heated liquid 22 for 1 to 24 hours. Therefore, in order to prevent such possible damage, testing device 20 may be oriented with filter 32 above liquid 22 and liquid-pressure source 34 (e.g., plunger 40) below filter 32, such that liquid 22 is not in contact with filter 32 during the heating, such as shown in
(129) Alternatively, in order to prevent the above-mentioned possible damage, for some applications, such as shown in
(130) Reference is now made to
(131) Reference is now made to
(132) Reference is now made to
(133) In step 1202, after incubation, an RST, e.g., a lateral flow test, is performed on the mixture of gargled fluid and growth medium. For some applications, the RST may be one of the following: an ELISA-based RST, an antibody-coated-beads-based RST, a nucleic-acid-based RST, and a fluorescent immunoassaying (FIA) RST. As supported by the experimental data set forth hereinbelow in the section entitled, “Measuring Group A Beta-Hemolytic Streptococcus Bacteria in Throat Gargle: Results of Overnight Growth in Liquid Media, Assayed by Rapid Strep Test,”, a number of methods used for performing the RST yield usable results, as follows: RST is performed on the mixture of gargled fluid and growth medium while the gargled fluid and growth medium are in the container. This method of RST is referred to as “whole tube RST” in the experimental data. At least a portion, e.g., at least 0.05 ml, e.g., 0.1 ml, of the mixture of gargled fluid and growth medium is transferred to another container, and the RST is performed on the portion of the gargled fluid and growth medium in the other container. This method of RST is referred to as “sample RST” in the experimental data. For some applications, the portion of the mixture is transferred by inserting an absorbent element, e.g., a swab, e.g., a flocked, cotton, or polyester swab, into the mixture of gargled fluid and growth medium and then placing the swab into the other container. Alternatively, if an absorbent element, e.g., a swab, was used to transfer liquid 22, e.g., the gargled fluid, into the container with growth medium, then that same absorbent element, e.g., swab may be removed and used to transfer the portion of the mixture into the other container for “sample RST.” For some applications, the portion of the mixture is transferred into the container, e.g., test tube 85, by other means, such as for example, pouring, using a syringe, using a pipette, or a pump. At least a portion of the mixture of gargled fluid and growth medium, after incubation, is filtered, e.g., passed through a filtration membrane (optionally, using any of the filtering devices described herein), and the RST is performed on the filter. This method of RST is referred to as “filter RST” in the experimental data.
(134) Results of a clinical trial performed by the inventors, including twenty-eight patients, are shown in Tables 1A-1D of
(135) Reference is now made to
(136) In step 1206, after incubation, an RST, e.g., a lateral flow test, is performed on the mixture of saliva and growth medium. For some applications, the RST may be one of the following: an ELISA-based RST, an antibody-coated-beads-based RST, a nucleic-acid-based RST, and a fluorescent immunoassaying (FIA) RST. As supported by the experimental data set forth hereinbelow in the section entitled, “Measuring Group A Beta-Hemolytic Streptococcus Bacteria in Saliva Sample: Results of Overnight Growth in Liquid Media, Assayed by Rapid Strep Test,” and similarly to as described hereinabove with reference to
(137) In a clinical trial performed by the inventors, 28 patients were asked to suck on a flocked swab for about ten seconds. The saliva swabs were then inoculated onto blood plates, and beta-hemolytic colonies were counted using a light table. As illustrated by Table 5 of
(138) As illustrated by the experimental data, experiments were also carried out by the inventors using saliva swab simulations by dipping swabs into pure GAS bacteria suspensions (referred to as “saliva swab simulation 1” in the experimental data) or into gargled fluid that was spiked with GAS bacteria (referred to as “saliva swab simulation 2” in the experimental data). The data presented in Table 7 of
(139) Almost all saliva swab clinical samples which were inoculated into Todd Hewitt (TH) broth and assayed by backup methods using RST methods yielded either true positive or true negative results for all subjects enrolled in phase 2 of the Proof of Concept Clinical Trial, seen in Table 9 of
(140) Reference is now made to
(141) Testing device 1020 comprises: liquid container 30 for containing liquid 22; filter 32, disposed in or downstream of liquid container 30; and plunger head 42, which (a) is shaped so as to be insertable into liquid container 30, (b) is configured to apply pressure to drive liquid 22 from liquid container 30 through filter 32, and (c) has downstream surface 80.
(142) Downstream surface 80 is at least partially coated with a solid (e.g., dehydrated and/or powdered) or semi-solid (e.g., gel and/or paste) growth medium 1022. For example, growth medium 1022 may comprise agar.
(143) For some applications, a cap 1024 is provided that is configured to be coupled to and fully cover growth medium 1022 on downstream surface 80 of plunger head 42. For example, cap 1024 may be transparent to enable observation of the culture on downstream surface 80 without removing the cap.
(144) Typically, plunger head 42 is shaped so as to be insertable into liquid container 30 so as to form a movable seal with a wall of liquid container 30. For some applications, testing device 1020 further comprises a plunger shaft 1031, and plunger head 42 is disposed at a downstream end portion of plunger shaft 1031. Plunger 40 (including plunger head 42 and plunger shaft 1031) may implement any of the configures of plunger 40 described hereinabove with reference to
(145) For some applications, a method for using testing device 1020 comprises: pushing plunger head 42 to apply pressure to drive liquid 22 from liquid container 30 through filter 32; touching downstream surface 80 of plunger head 42 to filter 32; particulate 1023, such as bacteria, on filter 32 are captured by growth medium 1022 on downstream surface 80; and assessing downstream surface 80 of plunger head 42 for biological growth.
(146) Typically, downstream surface 80 is placed directly in an incubator before assessing, thereby obviating the need to use another device to take a backup sample and plate it onto agar. Downstream surface 80 is optionally accessed by decoupling upstream component 70 from downstream component 72, such as described hereinabove with reference to
(147) For some applications, liquid 22 includes at least one substance selected from the group of substances consisting of gargled fluid, saliva not swabbed from the throat of a patient, and an incubated culture medium containing a biological sample.
(148) For some applications, downstream surface 80 of plunger head 42 is assessed for biological growth of a biological particulate selected from the group consisting of: a microorganism, a fungus, a bacterium, a spore, a virus, a mite, a biological cell, a biological antigen, a protein, a protein antigen, and a carbohydrate antigen. For some applications, plunger head 42 is heated before downstream surface 80 of plunger head 42 is assessed for biological growth.
(149) Reference is now made to
(150) The method comprises: pushing plunger head 42 to apply pressure to drive liquid 22 from liquid container 30 of testing device 1120 through filter 32; touching downstream surface 80 of plunger head 42 to filter 32; thereafter, touching downstream surface 80 of plunger head 42 to culture medium 1126 contained in a culture-medium container 1128, such as a petri dish; for example, culture medium 1126 may include agar; heating culture-medium container 1128; and assessing culture-medium container 1128 for biological growth.
(151) For some applications, liquid 22 includes at least one substance selected from the group of substances consisting of gargled fluid, saliva not swabbed from the throat of a patient, and an incubated culture medium containing a biological sample.
(152) For some applications, culture-medium container 1128 is assessed for biological growth of a biological particulate 1023 selected from the group consisting of: a microorganism, a fungus, a bacterium, a spore, a virus, a mite, a biological cell, a biological antigen, a protein, a protein antigen, and a carbohydrate antigen.
(153) Downstream surface 80 is optionally accessed by decoupling upstream component 70 from downstream component 72, such as described hereinabove with reference to
(154) For some applications, plunger head 42 is rotated while touching downstream surface 80 of plunger head 42 to filter 32 to increase the sample taken from filter 32, such as by macerating or grinding the filter. For applications in which downstream surface 80 is decoupled from upstream component 70 by rotation, this rotation may itself increase the sample taken from filter 32.
(155) For some applications, downstream surface 80 of plunger head 42 is rough, i.e., is shaped so as to define many small protrusions 1122, such as like sandpaper, or with plastic protrusions, in order to collect a better sample of particulate 1023 by macerating or grinding the filter.
(156) For some applications, touching downstream surface 80 of plunger head 42 to filter 32 comprises grinding filter 32 with rough downstream surface 80.
(157) For some applications, the method further comprising testing, within testing device 1120, for the presence of biological particulate 1023 trapped by filter 32, such as described hereinabove. In these applications, the sample taken from downstream surface 80 of plunger head 42 is used to perform a backup test, e.g., a backup strep test, for the rapid test performed inside testing device 1120, as described hereinabove.
(158) Reference is now made to
(159) Reference is also made to
(160) Testing device 1320 is configured such that rotation of plunger head 1342 radially compresses filter 32 toward a central longitudinal axis 1364 of plunger head 1342, as shown in
(161) For some applications, plunger head 1342 comprises a protrusion 1366 (best seen in
(162) For some applications, liquid container 1330 is shaped so as to define a filter-support surface 1371 surrounding downstream opening 1378. Filter-support surface 1371 supports a radial portion 1373 of filter 32 excluding a central portion 1375 of filter 32 (the central portion 1375 is typically removably disposed over downstream opening 1378). Filter-support surface 1371 is shaped so as to define a spiral groove 1377. Protrusion 1366 is configured to engage spiral groove 1377 through filter 32. Testing device 1320 is configured such that the rotation of plunger head 1342 (such as by between one-third of a turn to 10 turns) causes spiral groove 1377 to guide protrusion 1366 radially toward central longitudinal axis 1364 of plunger head 1342.
(163) Reference is now made to
(164) As shown in
(165) As shown in
(166) As shown in
(167) As shown in
(168) For some applications, testing machine 1310 comprises a waste liquid receptacle 1346, into which liquid 22 is driven after passing through filter 32. Typically, waste liquid receptacle 1346 is large enough to accommodate tests performed using several testing devices 1320.
(169) Reference is again made to
(170) Testing kit 1390 does not comprise a plunger shaft. Instead, plunger head 1342 is removably coupled to plunger shaft 1341 of testing machine 1310, as described above with reference to
(171) Although testing kit 1390 has been described with reference to liquid container 1330 and plunger head 1342, testing kit 1390 may alternatively comprise any of the other liquid containers described herein or another liquid container known in the art, and/or plunger head 1342 may alternatively comprise any of the other plunger heads described herein or another plunger head known in the art.
(172) For some applications, sterile packaging is provided, in which at least liquid container 1330, plunger head 1342, and filter 32 are removably disposed. The sterile packaging comprises one or more sterile packages; for example, each element may be removably disposed in a separate one of the packages, and/or more than one the elements may be disposed in a single one of the packages.
(173) Although techniques for testing, including rapid testing, are generally described herein as being performed for detecting strep, they may also be used to detect other biological particulate, such as a virus. For example, for detecting a virus, the filters described herein may capture epithelial cells that include the virus.
(174) Measuring Group a Beta-Hemolytic Streptococcus Bacteria in Throat Gargle:
(175) Results of Overnight Growth in Liquid Media, Assayed by Rapid Strep Test
(176) In some applications of the present invention, group A streptococcus bacteria (GAS) can be detected in throat gargle by two primary method types: Direct (“Immediate”) methods and Indirect (“Backup”) methods. Immediate methods yield results faster than Backup methods (<20 minutes vs. 12-48 hours) but are not as sensitive (higher rate of false negatives).
(177) In a clinical experiment performed by the inventors, Backup methods for GAS detection in throat gargle were tested. The experimental data is based on two types of GAS throat gargle simulations: pure GAS liquid suspension and throat gargle spiked with GAS. The Clinical Trial data is based on throat gargles obtained from patients with GAS pharyngitis who were enrolled in phase 2 of a Proof of Concept Clinical Trial (Protocol Number: STRP.P001, SNIH Clinical Trial Number: NCT03231098, Shaare Zedek Medical Center Helsinki IRB Number: SZMC-0181-17).
(178) Materials and Methods
(179) Bacterial Culture: 10 GAS strains were used: 1 standard control strain and 9 wildtype strains. The control GAS strain was American Type Culture Collection (“ATCC”) 19615, a strain often used for quality control, and the wildtype GAS strains were isolated during Clinical Trials and labeled WT-1 through WT-9. All GAS bacteria used in experiments were taken from 1-7 days old cultures on blood agar plates stored at 4-8° C.
(180) Growth conditions: The bacteria were routinely grown in a 37° C. incubator, without agitation. Liquid cultures were grown in 4 mL plastic test tubes, with liquid volumes of 0.45 mL, 0.6 mL, 1.0 mL, 1.1 mL, and 3.6 mL after inoculation. Cultures were incubated for 12-75 hours.
(181) Growth media: Blood plate media: Standard 90 mm plate (Petri dishes) containing TSA+5% sheep blood. Blood plates were purchased from Hylabs (Rehovot, Israel, Cat. No. PD-049). Liquid media: Tryptic Soy Broth (“TSB”), which is a well-known general-purpose growth media. Sterile TSB tubes were purchased from Hylabs (Cat. No. TT139). Liquid media: Todd Hewitt broth (“TH”), which is a media specifically developed to grow Streptococci. TH powder was purchased from Sigma Aldrich (Missouri, USA, Cat. No. T1438-500g). The media was prepared and sterilized by filtration through 0.2 um filtration units. The liquid growth media was prepared with 4.5 times the concentration recommended in the instructions. At this higher concentration, the liquid growth media had the following concentrations: glucose: 9 g/L; nitrogen source: 135 g/L; inorganic molecules: 22.05 g/L; and total solids: 166.5 g/L (as shown in the 4.5 row of Table 11, described hereinbelow.
(182) Bacterial suspensions: Pure GAS bacterial suspensions were made by transferring GAS colonies from culture into sterile Phosphate Buffer Saline (“PBS”).
(183) Bacterial counts: 0.05 mL or 0.1 mL samples of bacterial suspensions or throat gargles were inoculated onto blood plates without dilution and with using the appropriate limiting dilutions (dilutions of 10-fold to 8000-fold) and beta-hemolytic colonies were counted using a light table.
(184) Throat gargle: Throat gargles were obtained by gargling 10-11 mL PBS for approximately 10 seconds.
(185) Gargle spiked with GAS: Pure GAS liquid suspensions were added to gargle and diluted with gargle as necessary.
(186) RST methods: Lateral flow immuno-assay RST kits were purchased from Moore Medical (Connecticut, USA, Cat. No. 82792). Standard RST: Conducted according to manufacturers' instructions. Swab containing specimen sample was placed into a tube containing 8 drops of RST solutions, agitated slightly, and removed after 1-3 minutes. RST dipstick was then added to tube and removed after 5 minutes. 0.1 mL Sample RST: Similar to standard RST. 0.1 mL of specimen sample was added to tube containing RST solutions instead of a swab. Whole tube RST: 8 drops of RST solutions were added directly into tubes containing liquid culture media (0.4 mL, 0.9 mL, or 3.0 mL) incubated with gargle or simulated gargle, and RST dipstick was added to tube 1-3 minutes after addition of RST solutions. Filter RST: Culture media incubated with gargle or simulated gargle was filtered, membrane filter containing concentrated specimen sample was placed into a tube, 8 drops of RST solutions were added, and tube contents were mixed by a blunt tip for 30-45 seconds. The RST dipstick was added to the filter mixture approximately 3 minutes after addition of RST solutions.
(187) Summary of Results
(188) Of the 28 patients enrolled in phase 2 of the Proof of Concept Clinical Trial, 19 patients had true positive results from Backup Test methods performed using RST methods and 9 patient had true negative results from Backup Test methods performed using RST methods, as displayed in Table 1A-1D of
(189) The data in Table 1B-1D of
(190) Overall, 78 experimental systems containing simulated GAS gargles yielded true positive RST results, as detailed in Table 2 of
(191) Minimum incubation time was 12 hours, as set forth in Table 3 of
(192) The data in Table 4 of
(193) Conclusions
(194) These experimental data support the Backup method for GAS detection in throat gargle that involves the incubation of a sample of unfiltered throat gargle in liquid culture media for 12 to 75 hours followed by lateral flow RST immunoassay. A total of 53 systems from 28 patients enrolled in phase 2 of the Proof of Concept Clinical Trial all yielded either true positive or true negative results. A total of 78 experimental systems yielded positive Backup Test methods performed using RST results in multiple conditions. The Filter RST Backup method is presented as the most sensitive Backup Test method performed using a RST method, but all Backup Test methods performed using RST methods were satisfactory.
(195) Measuring Group a Beta-Hemolytic Streptococcus Bacteria in Saliva Sample:
(196) Results of Overnight Growth in Liquid Media, Assayed by Rapid Strep Test
(197) In some applications of the present invention, group A streptococcus bacteria (GAS) can be detected from saliva swab by Indirect (“Backup”) methods. In a clinical experiment performed by the inventors, Backup methods for GAS detection from saliva swab were tested. The experimental data is based on GAS growth simulations and the Clinical Trial data is based on saliva swabs obtained from patients with GAS pharyngitis who were enrolled in phase 2 of a Proof of Concept Clinical Trial (Protocol Number: STRP.P001, SNIH Clinical Trial Number: NCT03231098, Shaare Zedek Medical Center Helsinki IRB Number: SZMC-0181-17).
(198) Materials and Methods
(199) Bacterial Culture: 10 GAS strains were used: 1 standard control strain and 9 wildtype strains. The control GAS strain was American Type Culture Collection (“ATCC”) 19615, a strain often used for quality control, and the wildtype GAS strains were isolated during Clinical Trials and labeled WT-1 through WT-9. All GAS bacteria used in experiments were taken from 1-7 days old cultures on blood agar plates stored at 4-8° C.
(200) Growth conditions: The bacteria were routinely grown in a 37° C. incubator, without agitation. Liquid cultures were grown in 4 mL plastic test tubes, with liquid volumes of 0.9-1.1 mL after inoculation. Cultures were incubated for 12-75 hours.
(201) Growth media: Blood plate media: Standard 90 mm plate (Petri dishes) containing TSA+5% sheep blood. Blood plates were purchased from Hylabs (Rehovot, Israel, Cat. No. PD-049).
(202) Liquid media: Todd Hewitt broth (“TH”), which is a media specifically developed to grow Streptococci. TH powder was purchased from Sigma Aldrich (Missouri, USA, Cat. No. T1438-500g). The media was prepared and sterilized by filtration through 0.2 um filtration units. The liquid growth media was prepared with 4.5 times the concentration recommended in the instructions. At this higher concentration, the liquid growth media had the following concentrations: glucose: 9 g/L; nitrogen source: 135 g/L; inorganic molecules: 22.05 g/L; and total solids: 166.5 g/L (as shown in the 4.5 row of Table 11, described hereinbelow.
(203) Swabs: Flocked Swabs: Swabs with a tip of short nylon brush-like fibers designed for efficient absorption and elution, purchased from Puritan Diagnostics (Maine, USA, Cat. No. 25-3306-H). Cotton Swabs: Swabs with a tip comprised of a cotton matrix, purchased from Kodan Medicam (Bet Shemesh, Israel, Cat. No. 1102245).
(204) Polyester Swabs: Swabs with a tip comprised of a polyester matrix, manufactured by Puritan Diagnostics (Guilford, Main, USA), Cat. No. 25-806 1PD SOLID).
(205) Bacterial suspensions: Pure GAS bacterial suspensions were made by transferring GAS colonies from culture into sterile Phosphate Buffer Saline (“PBS”).
(206) Gargle spiked with GAS: Throat gargles were obtained by gargling 10-11 mL PBS for approximately 10 seconds and pure GAS suspensions were added to gargle and diluted with gargle as necessary.
(207) Saliva swabs: Saliva swabs were obtained from patients enrolled in the Clinical Trial. Patients were asked to suck on a flocked swab for approximately 10 seconds. Saliva swabs obtained from Clinical Trial subjects were inoculated onto blood plates and beta-hemolytic colonies were counted using a light table. Some saliva swabs were then inoculated into TH culture media and swab was left in culture media during incubation. Both the culture media and the swab were later assayed by Backup methods performed using RST methods.
(208) RST methods: Lateral flow immuno-assay RST kits were purchased from Moore Medical (Connecticut, USA, Cat. No. 82792). Swab sample RST: After incubation, saliva swab was removed from culture media and placed into a tube containing 8 drops of RST solutions, agitated slightly, and removed after 1-3 minutes. RST dipstick was then added to tube and removed after 5 minutes. 0.1 mL sample RST: Similar to swab RST. 0.1 mL of specimen sample was added to tube containing RST solutions instead of a swab. Whole tube RST: In some cases, the 8 drops of RST solutions were added directly into tubes containing GAS in liquid culture media (0.9-1.1 mL) and RST dipstick was added to liquid culture media tube 1-3 minutes after addition of RST solutions. Filter RST: Culture media incubated with saliva swab was filtered, membrane filter was placed into a tube, 8 drops of RST solutions were added, and tube contents were mixed by a blunt tip for 30-45 seconds. The RST dipstick was added to the filter mixture approximately 3 minutes after addition of RST solutions.
(209) Saliva swab simulation 1: Swabs were dipped into tubes containing pure GAS bacteria suspensions and agitated up and down 12-20 times before being removed for testing. Swabs were then inoculated onto blood plates and beta-hemolytic colonies were counted using a light table.
(210) Saliva swab simulation 2: Swabs were dipped 5 times into tubes containing gargle spiked with GAS bacteria and then dipped 5 times into TH culture media to inoculate. Swabs were discarded prior to incubation of the culture media.
(211) Bacterial counts: 0.05 mL or 0.1 mL samples of bacterial suspensions were inoculated onto blood plates using the appropriate limiting dilutions (dilutions of 8,000-fold or 30,000-fold) and beta-hemolytic colonies were counted using a light table.
(212) Summary of Results
(213) GAS was successfully captured from almost all plated saliva swab samples of positive subjects enrolled in phase 2 of the Proof of Concept Clinical Trial, as seen in Table 5 of
(214) As presented in Table 6 of
(215) After performing the experiment reflected in Table 6, the inventors appreciated that the data presented in Table 6 is invalid due to inaccurate testing. Due to the removal of some of the sample (for inoculating onto blood plates) prior to testing, as described above, the Backup methods using RST methods yielded inaccurate results, because the full sample was not tested. Subsequent clinical trial samples were tested properly utilizing the complete saliva sample (Patients 17-34), as described hereinbelow with reference to Table 8 of
(216) Saliva swab simulation 1 shows that flocked swabs are the preferred swab for obtaining a salvia swab sample, as can be seen in Table 7 of
(217) Saliva swab simulation 2 shows that flocked swabs, when used to inoculate a sample into TH culture broth for a Backup Test performed using RST methods, are as efficient as direct liquid transfer, as can be seen in Table 8 of
(218) Almost all saliva swab clinical samples which were inoculated into Todd Hewitt (TH) broth and assayed by Backup methods using RST methods yielded either true positive or true negative results for all subjects enrolled in phase 2 of the Proof of Concept Clinical Trial, seen in Table 9 of
(219) Conclusions
(220) These experimental data support the Backup method for GAS detection using a saliva sample via the incubation of a saliva swab in liquid culture media followed by lateral flow RST immunoassay. Plated clinical saliva swab samples displayed a 94.7% successful capture rate of GAS which confirms that saliva samples are a viable alternative to gargling in cases where gargling is not possible. Saliva swab simulations support the concept that Backup Test methods performed using RST methods of saliva swabs incubated in liquid media is an efficient method for GAS detection. Additional saliva swab simulation data shows that flocked swabs increase the uptake and release of specimen samples compared to other swabs.
(221) Clinical data from 18 samples demonstrates that a saliva swab Backup Test performed using RST methods in liquid media has high sensitivity (90%) and specificity (100%). Furthermore, the Filter Backup Test methods performed using RST methods yielded a higher sensitivity (90%) than the Swab Backup method performed using RST methods (80%).
(222) A liquid growth medium and a method of using the liquid growth medium are provided for testing for the presence of group A streptococcus bacteria (GAS) in a sample of oral fluid obtained from a patient, in accordance with respective applications of the present invention. The liquid growth medium and/or the method may be used in combination with any of the techniques described hereinabove in which growth medium is used for testing for the presence of biological particulate, such as strep, e.g., GAS. Although the liquid growth medium and the method are generally described hereinbelow as being appropriate for testing for the presence of GAS, they may also be used to test for other types of streptococcus bacteria, other types of bacteria, a microorganism, a fungus, a spore, a virus, a mite, a biological cell, a biological antigen, a protein, a protein antigen, or a carbohydrate antigen.
(223) The liquid growth medium has a substantially greater total nitrogen source concentration and a substantially greater total solids concentration than conventional liquid growth media used for incubating GAS. The liquid growth medium has a substantially greater osmotic value (indicative of the total concentration of molecules in the media) than conventional liquid growth media. In particular, the liquid growth medium typically has (a) a total nitrogen source concentration between 75 and 300 g/L and (b) a total solids concentration between 92.5 and 370 g/L.
(224) The high-concentration liquid growth medium may be particularly useful for successfully growing low concentrations (typically between 100 and 500 CFU/ml) of GAS present in samples of oral fluid, such as gargled fluid gargled by the patient or saliva not swabbed from a throat of the patient. These samples of oral fluid typically contain many dozens of types (often over 100) of other types of interfering bacteria. As described below, the inventors have found that the use of conventional, lower concentration liquid growth media for testing for the presence of GAS in samples of oral fluid (rather than samples swabbed from the tonsils, as is conventional in strep testing) results in consumption of most of the nutrients in the liquid growth medium by the interfering bacteria, leaving insufficient nutrients to grow the GAS of interest to an extent adequate for accurate testing.
(225) Many bacterial liquid growth media are used commercially to grow Group A streptococcus bacteria.
(226) They all contain at least 2 of the following three types of components:
(227) a. A sugar, usually glucose, as an energy source.
(228) b. Nitrogen sources as building blocks for nitrogen and carbon.
(229) c. Inorganic salts and molecules that serve as nutrients, as buffers to maintain pH during growth and to maintain osmotic balance.
(230) The table below shows the respective concentrations of the abovementioned three components in some of the widely used, commercially available liquid growth media formulations (which can be obtained from many manufactures all over the world). The following are examples of typical formulations.
(231) TABLE-US-00001 TABLE 10 Nitrogen Inorganic Total Formulation name Glucose Source molecules solids Todd Hewitt Broth 2 g/L 30 g/L 4.9 g/L 37 g/L Brain Heart Infusion 2 g/L 27.5 g/L 7.5 g/L 37 g/L Tryptic Soy Broth 2.5 g/L 20 g/L 7.5 g/L 30 g/L Columbia Broth 2.5 g/L 23.1 g/L 9.41 g/L 35 g/L Nutrient Broth None 20 g/L 5 g/L 25 g/L Thioglycollate broth 5.5 g/L 20.5 g/L 3 g/L 29.75 g/L
(232) Thus, a typical conventional liquid growth media for streptococcal growth will contain=<30 g/L of nitrogen sources, >10 g/L of Inorganic molecules, >40 g/L of total solids. These conventional liquid growth media, having the respective concentrations as shown in Table 10, all enable good growth of GAS in pure form.
(233) Furthermore, the use of a high-concentration liquid growth medium is conventionally believed to depress the growth of GAS. See, for example, Bernheimer, A. W. and Pappenheimer A. M. Jr., “Factors necessary for massive growth of Group A hemolytic Streptococcus”. Journal of Bacteriology, Volume 43(4), pages 481-494 (1941).
(234) As described hereinabove, the liquid growth medium of the present application has a substantially greater osmotic value (indicative of the total concentration of molecules in the media) than conventional liquid growth media. For some applications, the total nitrogen source concentration is between 105 and 180 g/L, such as between 120 and 160 g/L, and/or the total solids concentration is between 130 and 222 g/L, such as between 148 and 193 g/L.
(235) Typically, the liquid growth medium has a pH of between 6 and 8.3, such as between 7.0 and 8.0.
(236) For some applications, the liquid growth medium has a total sugar concentration of between 6 and 20, such as between 6 and 12. For some of these applications, the liquid growth medium has a glucose concentration of between 7 and 10, such as between 8 and 9.5.
(237) For some applications, an assembly is provided that includes the liquid growth medium and a sealed sterile container that contains the liquid growth medium.
(238) For some applications, an assembly is provided that includes the liquid growth medium and a container that contains the liquid growth medium and a sample of oral fluid obtained from a patient, such as described above.
(239) For some applications, a kit is provided that includes the liquid growth medium and a lateral flow strep test strip, one or more extraction reagents, and/or a filter.
(240) In an application of the present invention, a method of preparing the liquid growth medium includes adding a quantity of powdered growth medium to a volume of distilled water, and stirring until the powdered growth medium is dissolved in the distilled water to produce the liquid growth medium. The quantity of powdered growth medium and the volume of the distilled water are typically selected such that the liquid growth medium has (a) a total nitrogen source concentration between 75 and 300 g/L and (b) a total solids concentration between 92.5 and 370 g/L. The liquid growth medium may optionally have any of characteristics described above.
(241) In an application of the present invention, a method is provided for testing for the presence of GAS in a sample of oral fluid obtained from a patient, the method including: generating a biological product by incubating the sample of oral fluid for between 12 and 50 hours in a container that contains a liquid growth medium, the liquid growth medium having (a) a total nitrogen source concentration between 75 and 300 g/L and (b) a total solids concentration between 92.5 and 370 g/L; and thereafter, performing a strep test using a rapid strep test (RST) technique on the biological product.
(242) For some applications, incubating includes incubating for between 16 and 50 hours.
(243) Typically, the container does not contain agar. Alternatively, the container does contain some agar, but it is typically a relatively small amount compared to conventional strep culturing techniques.
(244) For some applications, performing the strep test using the RST technique includes performing a lateral flow test. For some applications, performing the strep test includes applying one or more extraction reagents to the biological product.
(245) Alternatively, for some applications, performing the strep test using the RST technique includes performing an RST technique selected from the group consisting of: an ELISA-based RST, an antibody-coated-beads-based RST, a nucleic-acid-based RST, and a fluorescent immunoassaying (FIA) RST.
(246) Typically, but not necessarily, the sample of oral fluid is selected from the group consisting of: gargled fluid gargled by the patient, and saliva not swabbed from a throat of the patient (e.g., spit by the patient, or sucked onto a swab by the patient).
(247) Alternatively, the sample of oral fluid is saliva swabbed from a tonsil of the patient.
(248) For some applications, generating the biological product further includes filtering the sample of oral fluid and the liquid growth medium after incubating. For some of these applications, performing the strep test using the RST technique includes performing the strep test using the RST technique on the filter. For some of these filtering applications, the sample of oral fluid is saliva swabbed from a tonsil of the patient.
(249) Typically, RST values below 0.25 (average of 5 and 10 minutes readings) are considered to be negative results. An RST value of 0.5 is indicative of a bacteria concentration of at least 10,000 CFU/ml
(250) The inventors performed experimentation where the lateral flow values of pure systems grown in TH-1 and TH-10 were compared with the lateral flow values of TH-1 systems with added salt (NaCl) or sugar (Glucose) at increasing concentrations. The Lateral flow value of TH-10 was similar to the values of TH-1+5% NaCl and 30% glucose.
(251) 5% Nacl and 30% glucose have similar Osmolarities, and inhibited the Strep to the same extent.
(252) From this a value of about 180 MOsmomolar was calculated, and a demonstration of Osmolarity dependent Strep A growth inhibition was shown, in agreement with scientific literature.
(253) A. The following is an experimental setup as performed by the inventors:
(254) 1. Each system consisted of a 5 ml test tube, containing 1.1 ml growth media.
(255) 2. 0.1 ml bacterial suspensions were added to each system and growth was started by incubation at 35.5° C., in air. Termination was done by withdrawal from the incubator and immediate processing, or by storage at 6-8° C. for up to 2 hours before processing.
(256) 3. The 0.1 ml bacterial suspensions were of 3 types: (a) In “pure” systems the bacteria were suspended in sterile Phosphate-Buffered Saline (“PBS”). (b) In “Gargle” systems the bacteria were suspended in a gargle solution. Gargle was obtained by gargling 10-11 ml of sterile PBS for about 10 seconds and then transferring the gargle to a collection cup. (c) In “saliva” systems the bacteria were suspended in saliva. Saliva was obtained by spitting into a collection cup.
(257) 4. Incubation was for a period of at least 4 hours but up to 3 days, depending on the experiment.
(258) 5. Two strains of GAS were used: the well-known “ATCC 19615” strain, which is used as a control strain in many diagnostic applications, and a wild-type strain “WT-9,” which was isolated from a patient in a clinical trial performed on behalf of the inventors.
(259) 6. Bacterial stock suspensions were obtained by resuspending in PBS a 1-4-days-old bacterial colony, grown at 35.5° C. on a blood agar plate for 1-2 days and then stored at 6-8° C. till used. The stock was diluted 10-250,000 fold, depending on the experiment, in either PBS, gargle or saliva. Bacterial dilutions of 4,800-20,000 in PBS were plated (50 microliters), grown at least overnight at 35.5° C., and the beta-hemolytic colonies counted.
(260) 7. Processing the samples involved assaying 0.1 ml of sample in an antigen lateral flow, Rapid Strip Test, for Streptococcus Group A. Test strips were obtained from McKesson company, USA, and used in accordance with the manufacture instructions. Estimation of the strength of the positive line was done visually, by experience lab workers.
Example 1
(261) The following Gargle/Saliva growth Media [GSM] were prepared based on the Todd Hewitt formula, with successively increasing concentrations of Glucose, Nitrogen Sources, and Inorganic molecules, as indicated in Table 11 below:
(262) TABLE-US-00002 TABLE 11 Nitrogen Inorganic Total Formulation name Glucose Source molecules solids Todd Hewitt Broth X 1 2 g/L 30 g/L 4.9 g/L 37 g/L (TH-1) Todd Hewitt Broth X 2.5 5 g/L 75 g/L 12.25 g/L 92.5 g/L (GSM -1) Todd Hewitt Broth X 4.5 9 g/L 135 g/L 22.05 g/L 166.5 g/L (GSM-2) Todd Hewitt Broth X 7 14 g/L 210 g/L 34.3 g/L 259 g/L (GSM-3) Todd Hewitt Broth X 10 20 g/L 300 g/L 49 g/L 370 g/L (GSM-4)
(263) 1.1 ml of each of the above sterile solutions was placed in a tube.
(264) Bacterial suspensions were prepared by spiking even number of bacteria cells in PBS×1, Gargle fluid and saliva.
(265) 0.1 ml of bacterial suspension was added to each of the above growth media shown in Table 11 and incubated at 35.5° C., in air, for 16.5-17.5 hours to obtain cultures.
(266) 0.1 ml of each culture was transferred each to a new tube containing Solution A (2M Sodium nitrite) and Solution B (0.2M Acetic acid) followed by a short mix on a Vortex mixer.
(267) McKesson RSTs were dipped into each solution and results were read after 5 and 10 minutes according to arbitrary test line intensity scale. Results are presented as the average between the 2 readings.
(268) Results
(269) The following Table 12 summarizes test results, which are reflected as well in
(270) TABLE-US-00003 TABLE 12 Growth Test Line intensity Media Pure Gargle Saliva TH-1 4.8 0.4 0.1 GSM-1 4.3 0.5 0.4 GSM-2 4.3 4.3 0.5 GSM-3 0.75 1 1.5 GSM-4 0.5 0.4 0.3
Conclusions
(271) Both gargle and saliva suspensions grow best in a GSM media having a high concentration of solids.
(272) As per the above results, the highest RST readings for gargle suspension growth resulted when GSM-2 was used.
(273) As per the above results, the highest RST readings for saliva suspension growth resulted when GSM-3 was used.
(274) Thus, the inventors have realized that the optimal range of solids concentrations in liquid growth media for growing gargle and saliva suspensions should be between 4.5-7×TH, i.e., 4.5-7 times the solids concentration in conventional Todd Hewitt liquid growth medium.
(275) In contrast to bacteria sourced from gargle fluid and saliva, the growth of pure GAS culture was inhibited by higher solids concentrations.
Example 2
(276) The following Gargle/Saliva growth Media [SPM] (shown in Table 14 below) were prepared based on a mix of several formulas as indicated in Table 13 below with successively increasing concentrations of Glucose, Nitrogen sources, and Inorganic molecules:
(277) TABLE-US-00004 TABLE 13 Brain Tryptic Formulation Todd Heart Soy Beef Yeast name Hewitt Infusion Broth Extract Extract Glucose Percentage of 4.44 g/L 6.66 g/L 3.9 g/L 10g /L 3 g/L 2 g/L total solids for SPMX 1
(278) TABLE-US-00005 TABLE 14 Nitrogen Inorganic Total Formulation name Glucose Source molecules solids SPM X 1 (SPM-1) 2.9 g/L 24.15 g/L 2.9 g/L 30 g/L SPM X 3.5 (SPM-3.5 10.15 85.525 10.15 105 g/L SPM X 4.5 (SPM-4.5) 13.05 108.675 13.05 135 g/L SPM X 6 (SPM-6) 17.4 144.9 17.4 180 g/L SPM X 7 (SPM-7) 20.3 169.05 20.3 210 g/L SPM X 8.5 (SPM-8.5) 24.65 205.275 24.65 255 g/L SPM X 10 (SPM-10) 29 g/L 241.5 g/L 29 g/L 300 g/L
(279) 1.1 ml of each of the above sterile solutions was placed in a tube.
(280) Bacterial suspensions were prepared by spiking even number of bacteria cells in PBS×1, Gargle fluid and saliva.
(281) 0.1 ml of bacterial suspension was added to each of the above growth media shown in Table 14 and incubated at 35.5° C., in air, for 22 hours to obtain cultures.
(282) 0.1 ml of each culture was transferred each to a new tube containing Solution A (2M Sodium nitrite) and Solution B (0.2M Acetic acid) followed by a short mix on a Vortex mixer.
(283) McKesson RSTs were dipped into each solution and results were read after 5 and 10 minutes according to arbitrary test line intensity scale. Results are presented as the average between the 2 readings.
(284) Results
(285) The following Table 15 summarizes test results, which are reflected as well in
(286) TABLE-US-00006 TABLE 15 Growth Media Pure Gargle Saliva SPM-1 4.1 1 0.4 SPM-3.5 3.8 0.6 0.4 SPM-4.5 3.8 1 0.4 SPM-6 4.4 1.6 0.5 SPM-7 1 2.5 1 SPM-8.5 0.5 3 4.4 SPM-10 0.5 0.6 0.25
(287) Thus, increasing the solids concentration in SPM growth media has a similar effect on GAS growth as shown using the GSM media of Example 1.
(288) Solid concentration of growth media has the same effect in both cases (Example 1 and Example 2) regardless of the media nutrient composition.
Example 3
(289) 1.1 ml of the TH-1 and 1.1 ml of GSM-1 growth media were each placed in respective tubes.
(290) Bacterial suspensions were diluted to the final respective cell counts specified in Table 16 below for both growth media formulas.
(291) 0.1 ml of each diluted bacterial suspension was added to a tube of TH-1 growth medium and to a tube of GSM-1 growth medium and incubated at 35.5° C., in air, for 23 hours, to obtain cultures.
(292) 0.1 ml of each culture was each transferred to a new tube containing Solution A (2M Sodium nitrite) and Solution B (0.2M Acetic acid) followed by a short mix on a Vortex mixer.
(293) McKesson RSTs were dipped in the solution and results were read after 5 and 10 minutes according to arbitrary test line intensity scale. Results are presented as the average between the 2 readings.
(294) Results
(295) Lateral flow values of cultures grown at 35.5° C. for 23h
(296) TABLE-US-00007 TABLE 16 CFU per tube Test line intensity Culture CFU per ml TH-1 TH-4.5 Pure 180 4.3 4 920 4 3.5 4590 4.6 4.5 45880 4 3.6 458800 4.2 3.9 Gargle 180 0.1 4.4 920 1 4.4 4590 2.5 4.3 45880 4 3.4 458800 4.6 2.8
Conclusions
(297) The range of cell numbers per ml in the above experiment represents the variability of cell counts in gargle fluids that were collected during clinical study conducted by Hero Scientific.
(298) GAS cells both from pure culture and gargle fluid grow well in TH×4.5 and can be easily detected by the RST.
(299) TH×1 is inferior to the high-solids concentration broth when gargle fluid is present in the broth at lower cell numbers. At higher cell numbers, even though TH-1 resulted in higher RST readings, TH-4.5 still resulted in sufficiently high readings so as to provide unambiguous results.
(300) In an embodiment, the techniques and apparatus described herein are combined with techniques and apparatus described in one or more of the following patent applications, which are assigned to the assignee of the present application and are incorporated herein by reference: International Application PCT/IL2018/050225, filed Feb. 28, 2018, which published as WO 2018/158768 to Fruchter et al.; U.S. Provisional Application 62/727,208, filed Sep. 5, 2018; and/or International Application PCT/IL2019/050994, filed Sep. 5, 2019, entitled, “Strep testing methods,” which published as WO 2020/049566 to Fruchter et al.
(301) It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.