Patent US2939861A successfully refreshed from Google Patents.
Patent EP0118274A1 successfully refreshed from Google Patents.
EP0118274A1
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Microbiological test processes
Assignee: Unilever PLC
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Filing: 1984-02-27
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Granted: —
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Expires: 2004-02-27
Abstract
Abstract Microbiological test processes and apparatus for identifying producers of penicillinase, in which a container for test incubation of a microorganism culture suspension with a cell density about 10 8 per ml is provided with penicillin, poor buffering and a fluorescent indicator, e.g. a coumarin such as 4-methyl-umbelliferone, in quantity sufficient to discriminate penicillinase producers and non-producers after incubation times over about one hour, e.g. up to 18 hours. The tests can then be conveniently combined with antibiotic sensitivity testing, e.g. in different microtitre wells of the same microtitre plate.
Inventors
- 👤 Anthony Hugh Carr
- 👤 Ian Jobling
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 00:59
CPC Classifications
C; C12; C12Q; C12Q1/00; C12Q1/34; C12Q1/02; C12Q1/04; C12Q1/18; C12Q2334/00; C12Q2334/20; C12Q2334/22; C12Q2337/00; C12Q2337/20; C12Q2337/22; G; G01; G01N; G01N2415/00
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
109 words
A microbiological test process for identifying microorganisms which are producers of beta-lactamase enzyme (penicillinase), which comprises incubating the microorganism under test with penicillin and an acid-base indicator, characterised in that the test is carried out by incubating an aqueous suspension of microorganisms, preferably containing of the order of 10 8 organisms per millilitre, in a container with a test medium poorly buffered against changes of pH and in the presence of an indicator substance capable of indicating the development of acidity by alteration of fluorescence, for an incubation time generally in excess of about one hour, e. g . 1-4 hours, or about 5 hours, or about 18 hours.
Claim 2
Dependent Claim
109 words
A microbiological test process for identifying microorganisms which are producers of beta-lactamase enzyme (penicillinase), which comprises incubating the microorganism under test with penicillin and an acid-base indicator, characterised in that the test is carried out by incubating an aqueous suspension of microorganisms, preferably containing of the order of 10 8 organisms per millilitre, in a container with a test medium poorly buffered against changes of pH and in the presence of an indicator substance capable of indicating the development of acidity by alteration of fluorescence, for an incubation time generally in excess of about one hour, e. g . 1-4 hours, or about 5 hours, or about 18 hours.
Claim 3
Dependent Claim
36 words
A process according to claim 1, characterised in that the test is carried out in the presence of a fluorophor showing reduced fluorescence in the presence of acid produced by the microorganism by hydrolysis of penicillin.
Claim 4
Dependent Claim
20 words
A process according to claim 2, characterised in that - the fluorophor is a fluorescent coumarin derivative, for example 4-methyl-umbelliferone.
Claim 5
Dependent Claim
41 words
A process according to claims 1, 2 or 3, characterised in that the poor buffering of the medium is sufficient to allow discrimination of lactamase positive and negative microorganisms after incubation times in the range about 5 hours to 18 hours.
Claim 6
Dependent Claim
31 words
A process according to claim 4, characterised in that the test medium contains buffering equivalent to a phosphate concentration in the range about 1-5 millimolar and an initial pH about 9.2.
Claim 7
Dependent Claim
46 words
A process according to any of claims 1-5, characterised in that the microorganism of which a suspension is tested is also subjected to a culture test to determine its antibiotic sensitivity, over a similar period of time as the period used for the test for beta-lactamase.
Claim 8
Dependent Claim
58 words
A process according to any of claim 1-5, characterised in that the test is carried out in a well of a microtitre plate of which other wells are used for carrying out antibiotic sensitivity testing of the same microorganism, and the microorganisms for both tests are sampled from a common suspension to ensure their identity with each other.
Claim 9
Dependent Claim
114 words
A microbiological test apparatus for identifying microorganisms which are producers of beta-lactamase enzyme (penicillinase), which comprises a carrier with penicillin and an acid-base indicator, characterised in that the test apparatus comprises a container for containing a suspension of the microorganism under test, and preserved in dry form in the container reagents for a test medium which is poorly buffered against changes in pE, including penicillin and an indicator capable of indicating the development of acidity by alteration of fluorescence, in quantity sufficient to allow discrimination of lactamase producers and non-producers after incubation times in excess of about one hour, e.g. 1 - 4 hours, or about 5 hours, or up to about 18 hours.
Claim 10
Dependent Claim
114 words
A microbiological test apparatus for identifying microorganisms which are producers of beta-lactamase enzyme (penicillinase), which comprises a carrier with penicillin and an acid-base indicator, characterised in that the test apparatus comprises a container for containing a suspension of the microorganism under test, and preserved in dry form in the container reagents for a test medium which is poorly buffered against changes in pE, including penicillin and an indicator capable of indicating the development of acidity by alteration of fluorescence, in quantity sufficient to allow discrimination of lactamase producers and non-producers after incubation times in excess of about one hour, e.g. 1 - 4 hours, or about 5 hours, or up to about 18 hours.
Claim 11
Dependent Claim
24 words
A microbiological test apparatus according to claim 8, further characterised by any one or more of the features specified in claims 2 to 7.
Claim 12
Dependent Claim
27 words
Microbiological test processes and apparatus according to claims 1 and 8, characterised by any one or more of the several features of the foregoing description and examples.
References Cited (Backward Citations)
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