US4250256A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microbiological test device
Assignee: Roche Diagnostics GmbH
•
Filing: 1979-06-01
•
Granted: 1981-02-10
•
Expires: 1999-06-01
Abstract
Abstract Microbiological test device having a nutrient card or cards and a covering layer thereover which is permeable to nutrients but impermeable to bacteria. The covering layer is made from an aqueous dispersion of a water insoluble resin and a pore former.
Inventors
- 👤 Hans Wielinger
- 👤 Walter Rittersdorf
- 👤 Manfred Bleisteiner
- 👤 Gerd Zimmermann
- 👤 Wolfgang Werner
- 👤 Wolfgang Vomel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:20
CPC Classifications
C; C12; C12M; C12M41/00; C12M41/30; C12M41/36; C12M23/00; C12M23/02; C12M23/14; Y; Y10; Y10S; Y10S435/00; Y10S435/805; Y10S435/81
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
69 words
Microbiological test device comprising a nutrient card and a covering layer which is impermeable to bacteria but permeable to nutrients, said covering layer comprising a water-insoluble synthetic resin film modified with a pore former which is a water-soluble or water-swellable compound, said film having been produced from an aqueous dispersion of the synthetic resin and wherein the pore former and resin film have no negative effect on bacterial growth.
Claim 2
Dependent Claim
69 words
Microbiological test device comprising a nutrient card and a covering layer which is impermeable to bacteria but permeable to nutrients, said covering layer comprising a water-insoluble synthetic resin film modified with a pore former which is a water-soluble or water-swellable compound, said film having been produced from an aqueous dispersion of the synthetic resin and wherein the pore former and resin film have no negative effect on bacterial growth.
Claim 3
Dependent Claim
34 words
Test device of claim 1 wherein the pore former is a polyethylene glycol, polyethylene oxide, polyvinylpyrrolidone, polyvinyl alcohol, partly saponified polyvinyl ester, a copolymer of vinylpyrrolidone and a vinyl ester or a cellulose derivative.
Claim 4
Dependent Claim
17 words
Test device of claim 2 wherein the cellulose derivative used as a pore former is a hydroxyalkylcellulose.
Claim 5
Dependent Claim
55 words
Test device of claim 1 wherein the synthetic resin film is a homopolymer of vinyl acetate or of an acrylic acid ester, a co-polymer of vinyl propionate and vinyl acetate, vinyl propionate and vinyl chloride, vinyl acetate and a maleic acid ester, an acrylic acid ester with acrylonitrile and vinyl propionate and butadiene and styrene.
Claim 6
Dependent Claim
18 words
Test device of claim 1 wherein the synthetic resin film has a thickness of from 10 to 1000μ.
Claim 7
Dependent Claim
20 words
Test device of claim 1 wherein the weight ratio of pore former to synthetic resin is from 5:1 to 1:50.
Claim 8
Dependent Claim
13 words
Test device of claim 1 wherein the film contains a synthetic resin mesh.
Claim 9
Dependent Claim
18 words
Test device of claim 7 wherein the synthetic resin mesh has a thickness of from 10 to 200μ.
Claim 10
Dependent Claim
19 words
Test device of claim 7 wherein the synthetic resin mesh is provided with colored markings at definite distances apart.
Claim 11
Dependent Claim
19 words
Test device of claim 1 wherein the covering layer contains at least one wetting agent, buffer, salt and/or nutrient.
Claim 12
Dependent Claim
22 words
Test device of claim 10 wherein the additional materials in the covering layer account for 0 to 15% of the weight thereof.
Claim 13
Dependent Claim
23 words
Test device of claim 1 wherein the covering layer contains at least one substance which inhibits and/or promotes the growth of particular micro-organisms.
Claim 14
Dependent Claim
12 words
Test device of claim 12 wherein the covering layer contains an antibiotic.
Claim 15
Dependent Claim
22 words
Test device of claim 1 wherein the nutrient card is a filtered paper impregnated with a nutrient solution conventionally used in microbiology.
Claim 16
Dependent Claim
23 words
Test device of claim 1 wherein the nutrient card contains at least one wetting agent, moisture-retaining agent, swelling agent, buffer, salt and/or antibiotic.
Claim 17
Dependent Claim
15 words
Test device of claim 1 wherein the nutrient card is attached to a water-resistant support.
Claim 18
Dependent Claim
22 words
Test device of claim 16 wherein the nutrient card is fixed in a pocket formed by the support and the covering layer.
Claim 19
Dependent Claim
28 words
Test device of claim 17 wherein the pocket is formed by adhering or sealing projecting edges of the covering layer adjacent to the nutrient card onto the support.
Claim 20
Dependent Claim
18 words
Test device of claim 16 wherein the support is provided with an elongation which serves as a handle.
Claim 21
Dependent Claim
15 words
Test device of claim 16 wherein the support is made of a synthetic resin foil.
Claim 22
Dependent Claim
22 words
Test device of claim 16 wherein a plurality of covering layers and/or nutrient cards of different composition are fixed to the support.
Claim 23
Dependent Claim
15 words
Test device of claim 21 wherein the compositions differ in the concentration of an antibiotic.
Claim 24
Dependent Claim
54 words
Method for determining micro-organism counts and for the differentiation of micro-organisms which comprises dipping a test device of claim 1 into a liquid to be investigated, wiping off excess liquid, incubating the device and counting the colonies of micro-organisms formed or differentiating the types of micro-organisms by the growth behavior thereof on various media.
Claim 25
Dependent Claim
34 words
Method of producing an antibiogram which comprises moistening a test device of claim 1 with a suspension of micro-organisms, depositing an antibiotic test leaflet thereon, incubating the device and thereafter determining the resistance behavior.
Claim 26
Dependent Claim
57 words
Method for the determination of the minimum inhibiting concentration of an antibiotic using a test device of claim 1, wherein the covering layer and/or nutrient card contains definite concentrations of the antibiotic, dipping the test device into a suspension of microorganisms, incubating the device and determining, the minimum inhibitor concentration which prevents the growth of the microorganisms.
References Cited (Backward Citations)
US2904474A
Cited
US3000706A
Cited
US3881993A
Cited
US3802842A
Cited
US3814670A
Cited
US4066511A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-10 | 1984-08-11 | 1985-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-10 | 1988-08-11 | 1989-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-10 | 1992-08-11 | 1993-02-10 | $7700.00 | Window Closed / Lapsed |