DETECTING MICROORGANISMS IN BLOOD UTILIZING PHYSICAL AND CHEMICAL CHANGES IN BLOOD

• US 20090115996A1
• Filed: 11/03/2008
• Published: 05/07/2009
• Est. Priority Date: 11/06/2007
• Status: Active Grant

• Current Assignee: Claro Scientific, LLC
• Original Assignee: Claro Scientific, LLC
• Inventors: Leparc, German F., SEREBRENNIKOVA, Yulia M., Smith, Jennifer M., Huffman, Debra, Garcia-Rubio, Luis H.
• Granted Patent: US 7,952,693 B2
• Time in Patent Office: Days
• US Class Current: 356/39
• CPC Class Codes: C12Q 1/04 Determining presence or kind of microorganism; Use of selective media for testing antibiotics or bacteriocides; Compositions containing a chemical indicator therefor C12Q1/6897 takes precedence
• CPC Class Codes: G01N 2021/3144 for oxymetry
• CPC Class Codes: G01N 2021/3155 Measuring in two spectral ranges, e.g. UV and visible
• CPC Class Codes: G01N 2021/4747 Concentric bundles
• CPC Class Codes: G01N 21/31 Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry G01N21/72 takes precedence
• CPC Class Codes: G01N 21/474 Details of optical heads therefor, e.g. using optical fibres
• CPC Class Codes: G01N 21/8507 Probe photometers, i.e. with optical measuring part dipped into fluid sample

Abstract

An approach to detecting microorganisms in blood uses the changes of hemoglobin and the physical and chemical properties of blood to detect the presence of microorganisms in blood. Spectrophotometric measurements are taken several wavelengths across the UV-Vis-NIR portion of the electromagnetic spectrum, and a deconvolution is performed quantitatively to interpret distinct spectral characteristics of blood enabling the detection of microorganisms.

Claims

1. A method for assessing the presence of microorganisms in blood, comprising:

(a) emitting electromagnetic radiation into at least one blood sample;

(b) measuring wavelength-dependent spectra of reemitted electromagnetic radiation from said blood sample, wherein said measuring is of one or both of transmittance signals and reflectance signals; and

then

(c) deconvoluting said spectra to assess the presence or absence of microorganisms in blood.

2. A method according to claim 1, wherein said spectra is quantitatively interpreted in terms of the physical and chemical properties of blood.

3. A method according to claim 1, wherein said deconvoluting determines the presence or absence of multiple types of microorganisms in blood.

4. A method according to claim 2, wherein said spectra can be measured as a function of time or at any discrete time point.

5. A method according to claim 1, wherein said measuring is of diffuse transmittance signals.

6. A method according to claim 1, wherein said measuring is of diffuse reflectance signals.

7. A method according to claim 1, wherein said measuring is of angular transmittance signals.

8. A method according to claim 1, wherein said measuring is of angular reflectance signals.

9. A method according to claim 1, wherein said re-emitted electromagnetic radiation comprises wavelengths in the ultraviolet range, the visible range, and/or the near-infrared range.

10. A method according to claim 1, wherein said deconvoluting step quantifies the physical properties of blood components.

11. A method according to claim 1, wherein said deconvoluting step (i) comprises at least one of linear or non-linear models and (ii) resolves said spectra into a particle-related physical characterization.

12. A method according to claim 1, wherein said deconvoluting step identifies and quantifies at least one form of hemoglobin.

13. A method according to claim 12, wherein said deconvolution (i) comprises at least one of a linear model and a non-linear model and (ii) resolves said spectra into said hemoglobin form.

14. A method according to claim 1, wherein said assessing comprises detecting the presence or absence of microorganisms.

15. A method according to claim 1, further comprising extracting identifying characteristics of the microorganisms from the spectra.

16. A method according to claim 15, wherein the identifying characteristics are selected from the group comprising kinetic growth parameters and physical characteristics.

17. A method according to claim 15, wherein the growth parameters include doubling times and respiration rates.

18. A method according to claim 15, wherein the physical characteristics include size and shape.

24. A method according to claim 1, wherein partial pressure values associated with at least one of oxygen and carbon dioxide are determined from the deconvoluted spectra.

25. The method of claim 1, wherein the presence or absence of microorganisms is assessed in accordance with changes in properties of blood induced by one or more microbial metabolites.

27. A method according to claim 25, further comprising identifying the at least one microorganism.

28. A method according to claim 25, wherein said assessing comprises detecting the presence of said microorganisms.

19. An apparatus configured to assess the presence of microorganisms, comprising:

(a) a spectrometer configured to measure spectra of a plurality of wavelengths emitting from a sample of blood;

(b) a transmission cell and/or a reflectance probe operably connected to said spectrometer; and

(c) a computer that (i) is connected operationally to said spectrometer and (ii) is configured to perform deconvolution on said spectra, thereby to assess the presence or absence of microorganisms in said sample.

20. An apparatus according to claim 19, wherein said deconvolution (i) comprises at least one of linear or non-linear regression techniques and (ii) can resolve said spectra into at least one form of hemoglobin.

21. An apparatus according to claim 19, wherein at least one of a reflectance probe and a transmission cell are operably connected to said spectrometer.

22. An apparatus according to claim 19, wherein said spectrometer includes a diode array.

23. An apparatus according to claim 21, wherein a reflectance probe is operably connected to said spectrometer and is configured to operate without making contact with a container in which said sample is located.

26. A method of assessing the presence of at least one microorganism in blood, comprising:

(a) emitting electromagnetic radiation into at least one blood sample in a closed container;

(b) measuring wavelength-dependent spectra of re-emitted electromagnetic radiation from said blood sample, wherein said measuring is of one or both of transmittance signals and reflectance signals;

(c) deconvoluting said spectra;

(d) determining partial pressure values associated with at least one of oxygen and carbon dioxide in a headspace above said blood sample; and

(e) assessing the presence or absence of microorganisms in accordance with said partial pressure values.

29. A method of assessing the presence of at least one microorganism in blood, comprising:

(a) emitting electromagnetic radiation into at least one blood sample in a thermodynamically closed container;

(b) measuring wavelength-dependent spectra of re-emitted electromagnetic radiation from said blood sample to obtain measured spectral values, wherein said measuring is of one or both of transmittance signals and reflectance signals;

(c) measuring partial pressure values associated with at least one of oxygen and carbon dioxide in a headspace above said blood sample to obtain measured partial pressure values;

(d) deconvoluting said spectra in accordance with said measured spectral values and said measured partial pressure values; and

(e) assessing the presence or absence of microorganisms in accordance with said deconvoluting.