Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or...
Reexamination Certificate
1999-08-23
2001-02-20
Leary, Louise N. (Department: 1623)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
C435S005000, C435S007200, C435S007210, C435S007220, C435S007310, C435S007320, C435S029000, C435S030000, C435S034000, C435S283100, C435S286600, C435S286500, C435S287100, C435S287500
Reexamination Certificate
active
06190858
ABSTRACT:
This invention relates to the detection of conditions, in particular to the detection of conditions in a patient and the detection of microorganisms by analysis of gases or vapors emitted therefrom.
It is known that many gaseous or volatile species can be detected and identified by so-called “electronic noses”, which are usually devices comprising an array of individual gas sensing elements. For example, the present applicants produce such an instrument having up to thirty two gas sensing elements, each element having a different semiconducting polymer. The semiconducting polymers typically display broad and overlapping responses towards gaseous species. However, this is turned to advantage when an array of such polymers is employed. On exposure to a gas or volatile species, the resistances of the semiconducting organic polymer vary—but to different extents. Thus the pattern of resistance variation across the array of sensors is indicative of the species being detected. Further information concerning polymers and the techniques used to interrogate them may be found in International Publication No. WO 96/00384 and references therein.
International Publication No. WO 95/33848 describes a method for detecting bacteria via detection of the characteristic vapors emanating therefrom as a result of bacterial metabolism by an array of gas sensors, in particular an array of semiconducting organic polymers of the type described above. The technique is of potentially wide and significant use in the medical area. However, to date, methods and apparatus suitable for practical, day to day use in a clinical environment have not been available. Furthermore, it would be desirable to detect and monitor a whole range of clinical conditions, which might include bacterial infections, but which might also include other conditions, such as viral or fungal infection.
The present invention addresses these problems and concerns.
According to a first aspect of the invention there is provided a method for monitoring at least one condition in a patient comprising the steps of:
obtaining samples from the patient over a period of time;
flowing the samples, or gases and/or vapors associated with, or produced by the samples, over at least one gas sensor;
measuring the response or responses of the at least one gas sensor as a function of time; and
correlating the response or responses with the occurrence or state of the at least one condition.
In this way, monitoring for the onset of a condition, or monitoring of the progression of a condition is possible, the data being obtained very rapidly, since laborious and time consuming culturing steps are not required.
The samples may comprise respiratory gases.
The samples may comprise swabbed samples obtained from the patient.
The samples may comprise blood.
The condition monitored may be a disease state, and the progression and/or regression of the disease state may be monitored.
The condition may be a bacterial infection.
The condition may be a viral, fungal or parasitic infection.
The response or responses may be correlated with the effectiveness of a course of treatment.
The response or responses may be correlated with the progress of a healing process.
The response or responses may be correlated with the occurrence or state of the condition or conditions by a trained neural network.
An array of gas sensors may be employed. The pattern of responses of the sensors in the array may be correlated with the occurrence of or state of at least one condition.
The samples may be obtained continuously from the patient. The samples, or gas and/or vapor associated with or produced by the samples, may be continuously flowed over the at least one gas sensor. In this way, on-line monitoring of conditions by reference to gases and vapors is possible.
The response or responses of the at least one gas sensor may be measured continuously.
Alternatively, a plurality of measurements may be made over a period of time.
The samples may comprise respiratory gases obtained from a ventilator.
The samples may comprise blood undergoing a dialysis treatment. Gases produced by a waste product containing solution may be measured by the at least one gas sensor. The removal of urea from the blood sample may be monitored by measuring ammonia evolved from the waste product containing solution.
According to a second aspect of the invention there is provided a method for identifying a micro-organism comprising the steps of:
providing at least one gas sensor;
compiling a database of responses to at least one known micro-organism under a variety of culturing conditions;
abstracting gas and/or vapor from a detection region and flowing the same over said the at least one gas sensor and observing the response of the sensor or sensors; and
comparing the response to the database.
The database may comprise responses to at least one known bacterium.
The database may comprise responses to a plurality of different isolates of a single bacterial species.
The mirco-organism may comprise a virus, fungus or parasite.
The database may comprise responses to at least one known micro-organism cultured under a variety of nutrient conditions.
The database may comprise responses to at least one known micro-organism cultured at a variety of temperatures.
The database may comprise responses to at least one known micro-organism obtained at different stages in the life cycle of the micro-organism.
The method may further identify at least one condition in a patient in which gas and/or vapor produced by the patient, or by a sample obtained from the patient, is flowed over the at least one gas sensor. At least a portion of the database may be compiled from responses of at least one gas sensor to gas or vapor produced by a patient, or by a sample obtained from the patient.
The database may comprise responses to at least one known micro-organism obtained at different stages during the course of treatment.
An array of gas sensors may be employed.
The compilation of the database may comprise training a neural network. In other words, the trained neural network is regarded as a “database” for the present purposes, and the pattern recognition processes employed by such networks are similarly regarded as “comparing the response to the database”.
The response of the sensors may be used to provide information about the detection region, such as the nutrient conditions, the nature of the substrate or the location of the detection region.
The gas sensor or sensors may comprise a gas sensitive material. An electrical property of the gas sensitive material may vary on exposure to gases and/or vapors.
The gas sensitive material may comprise semi-conducting polymer.
The gas sensor or sensors may comprise metal oxide semiconductor (MOS), quartz resonator or surface acoustic wave (SAW) devices.
REFERENCES:
patent: 0158497 (1985-10-01), None
patent: WO 94 04705 (1994-03-01), None
patent: WO 95 33848 (1995-12-01), None
patent: 99/09407 A1 (1999-02-01), None
Parry et al, “Leg Ulcer Odour Detection Identifies Beta-Haemolytic Streptococcal Infection”, Journal of Wound Care Oct., vol. 4, No. 9, 1995.
English translation of Berdagué et al, Viandes Prod. Carnés 14 (5) (1993) 135 Sep.-Oct.
S-W Ho, Chinese J. Microbiol Immunol. 19, (1986) 18 “Head-Space Gas-Liquid Chromatographic Analysis for Presumptive Identification of Bacteria in Blood Cultures”.
Shiyouzou, Patent Abstracts of Japan JP 60130398 (Nov. 7, 1985).
Schneider et al, Digestion 32: 86-91 (1985) (14C breath test for intestinal bacterial).
Gardner and Craven “Classification of bacteria age and type using an array of metal oxide sensors & pattern recognition techniques”, 3rdInternational Symposium on Olfaction and Electronic Noses, Nov. 3-6, 1996 (publication date not known).
Rosenberg (Ed) “Bad Breath: Research Perspectives” 1995.
Rossi et al “Rapid discrimination of meat products and bacterial strains using semiconductor gas sensors” Bioflavour Feb. 14-17, 1995.
Parry et al, “Detection of &bgr;-haemolytic streptococcal infection by analysis of leg ulcer odour”, Proc. Annual Conference of W
Persaud Krishna Chandra
Syms Allan John
Leary Louise N.
Osmetech PLC
Renner , Otto, Boisselle & Sklar, LLP
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