Microorganism culture detection unit and microorganism culture instrument

Abstract

The utility model discloses a microorganism culture detection unit which comprises a cavity for placing a culture container, and an installation space for installing an optical signal acquisition component is arranged below the cavity; the bottom of the culture container is provided with a sensor which is used for sensing the state of a sample and changing the color along with the change of the state of the sample; the light signal acquisition assembly comprises a light source and a receiver, the light source is used for projecting light to the inductor, and the receiver is used for receiving reflected light reflected by the inductor. The utility model further discloses a microorganism culture instrument which comprises an incubator, and at least one microorganism culture detection unit is arranged in the incubator. The microorganism culture detection unit and the microorganism culture instrument can meet the detection requirements of microorganism infection.

Description

Technical Field

[0001] This invention belongs to the field of in vitro diagnostic technology, specifically a microbial culture and detection unit and a microbial culture instrument. Background Technology

[0002] The principle of blood culture analysis is to qualitatively detect the presence of microorganisms by monitoring changes in turbidity, pH, CO2 concentration of metabolic products, and fluorescently labeled substrates or metabolic products in the culture medium (liquid). Based on different detection principles, it can be divided into four types: colorimetric, fluorescence, barometric, and electrode methods. Currently, the mainstream method is colorimetry. In colorimetry, a sensor is placed at the bottom of each culture bottle, and a semi-permeable silica membrane is placed between the culture medium and the sensor. Only CO2 can pass through this semi-permeable silica membrane. When microorganisms grow in the blood culture bottle, the released CO2 permeates to the sensor. After water saturation, it produces H+, changing the sensor's pH value and causing a color change from blue-green to yellow. As the CO2 concentration increases, the sensor's color becomes lighter, and the reflected light becomes stronger (the lighter the color, the higher the "reflectance unit" value). Therefore, in colorimetry, the presence of microbial growth can be determined by color changes.

[0003] The general method for detecting infection in blood involves culturing the blood and monitoring changes in the culture medium. If the growth of microorganisms in the culture medium exceeds a certain standard, it indicates infection. The monitoring method typically involves an LED light source projecting light onto a sensor, and a photodiode detecting the reflected light. As the CO2 concentration increases, the sensor becomes lighter, the reflected light becomes stronger, and the lighter the color, the higher the reflectance unit value. Different reflectance units are obtained over time. By comparing the initial reflectance units with the current reflectance units, a positive result (i.e., whether the blood sample is infected) is determined. If, after a certain number of days, the CO2 level does not change significantly, the instrument will report the culture bottle as negative.

[0004] However, when the sensor's color change is small, the change in reflectance is small, resulting in low response sensitivity. Clinically, this manifests as poor sensitivity to weakly growing bacteria, leading to false negatives and affecting the accuracy of the positive rate. Furthermore, environmental changes causing curve fluctuations can also impact accuracy. Current technologies typically improve accuracy by increasing response sensitivity, such as enhancing the sensor's sensitivity to CO2 or pH, but none of these methods consider the influence of the light source on accuracy. Summary of the Invention

[0005] Existing technologies all use single-wavelength LED light sources. Experimental verification has revealed two issues: First, when the color change of the sensor is small, the change in reflectance is small, resulting in low response sensitivity. Clinically, this manifests as poor sensitivity to weakly growing bacteria, easily leading to false negatives and affecting the accuracy of positive rate interpretation. Second, when environmental changes cause curve fluctuations, single-wavelength LED light source detection is prone to false positives, also affecting the accuracy of positive rate interpretation. Therefore, single-wavelength LED light source detection cannot adapt to a wide range of reflective substrates, and the reflectance data from a single-wavelength LED light source has limitations for interpretation.

[0006] In view of this, the purpose of this utility model is to provide a microbial culture and detection unit and a microbial culture instrument that can meet the detection requirements of microbial infection.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] This invention first proposes a microbial culture detection unit, including a cavity for placing a culture container, and an installation space for installing a light signal acquisition component below the cavity; the bottom of the culture container is provided with a sensor for sensing the sample state and changing color according to the change of the sample state; the light signal acquisition component includes a light source and a receiver, the light source is used to project light onto the sensor, and the receiver is used to receive the reflected light after being reflected by the sensor.

[0009] Furthermore, the light source is used to project at least two different colors of single wavelength light onto the sensor.

[0010] Furthermore, the light source is a single light source capable of emitting at least two different colors of single wavelength light; or, the light source includes a single light source capable of emitting white light and at least two filters capable of transmitting single wavelength light of different colors; or, the light source includes at least two light-emitting units, and different light-emitting units are capable of emitting single wavelength light of different colors.

[0011] Furthermore, the light source is a ring-shaped light source installed around the installation space, and the ring-shaped light source is provided with at least two light-emitting units, and different light-emitting units can emit single wavelengths of light of different colors.

[0012] Furthermore, at least a portion of the inner surface of the mounting space is a rough surface for eliminating stray light.

[0013] Furthermore, the rough surface is a sawtooth rough surface, a threaded rough surface, or a dotted raised rough surface.

[0014] Furthermore, the installation space includes a first installation area located below the cavity, the inner diameter of the first installation area gradually decreasing from top to bottom, and the light source is installed on the side wall of the first installation area.

[0015] Furthermore, the receiver is installed on the bottom surface of the first mounting area; or, a cylindrical mounting area is provided below the first mounting area, and the receiver is installed in the cylindrical mounting area.

[0016] Furthermore, the inner surface of the first mounting area is a conical or square pyramidal surface with an inner wall size that gradually decreases from top to bottom.

[0017] This invention also proposes a microbial culture instrument, including an incubator, wherein the incubator is provided with at least one microbial culture and detection unit as described above.

[0018] The beneficial effects of this utility model are as follows:

[0019] The microbial culture detection unit of this invention features a cavity for holding a culture container, with an installation space below the cavity where a light signal acquisition component is placed. A sensor is also positioned at the bottom of the culture container. Thus, a light source projects light onto the sensor at the bottom of the culture container; the reflected light is received by a receiver, and the reflected light signal received by the receiver provides a detection result indicating whether the sample is infected. Therefore, the microbial culture detection unit and microbial culture instrument of this invention can meet the requirements for detecting microbial infection.

[0020] This utility model also has the following technical effects:

[0021] By setting the light source to project at least two different colors of single-wavelength light onto the sensor, the reflected light signals of at least two different colors of single-wavelength light can be used to obtain the result indicating whether the sample is infected. This improves detection efficiency and the accuracy of positive rate determination, for the following reasons:

[0022] (1) When the color change of the sensor is small, since at least two different colors of single wavelength light are used, during the sample culture process, as the color of the sensor changes, at least one single wavelength light is close to or even the same as the color of the reactor. Thus, according to the principle of spectral reflection, light of similar or the same color (light with the same or similar wavelength) has a higher reflectance, which can increase the unit change in reflectance and thus improve the response sensitivity. Clinically, this means that it can improve the response sensitivity to weakly growing bacteria. On the one hand, it can improve the efficiency of preliminary positive interpretation, so that patients can receive timely treatment. On the other hand, it can also avoid false negative interpretation and improve the accuracy of positive rate interpretation.

[0023] (2) After obtaining a preliminary positive result, the preliminary positive result can be verified by using single wavelength light of other colors to improve the accuracy of the positive rate. In particular, when the environment changes, the reflected light information curve of a single wavelength light of a certain color may fluctuate, which may lead to a false positive result. However, for single wavelength light of other colors, the environmental change has little effect on the reflected light information curve and will not lead to a false positive result. In this way, by combining the reflected light information of single wavelength light of at least two colors, the influence of environmental change on the accuracy of the positive rate can be avoided.

[0024] In addition, under normal understanding, microbial culture instruments use strong signal detection, meaning the signal received by the receiver is strong enough to make accurate analysis. Therefore, from the perspectives of performance, cost, and difficulty, the interference of stray light is usually not considered and is not necessary. In this invention, the focus is on the time of positive result interpretation, especially the sensitivity for interpreting weakly growing bacteria, which led to the consideration of reducing noise to improve sensitivity. Furthermore, this invention uses a rough surface on the inner surface of the installation space to eliminate stray light, which helps improve sensitivity under specific conditions. In particular, the combination of single-wavelength light of multiple colors greatly shortens the positive result reporting time for weakly growing bacteria. Attached Figure Description

[0025] To make the objectives, technical solutions, and beneficial effects of this utility model clearer, the following drawings are provided for illustration:

[0026] Figure 1 This is a diagram illustrating the principle of spectral reflectance of a red object.

[0027] Figure 2 The spectral reflectance curves of objects of different colors are shown; (a) red object; (b) blue object; (c) green object.

[0028] Figure 3 This is a schematic diagram of the structure of an embodiment of the microbial culture unit of this utility model;

[0029] Figure 4 This is a graph showing how reflectance changes over time.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1-Cultivation container; 2-Installation space; 3-Sensor; 4-Receiver; 5-Light-emitting unit. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0033] Principle of Spectral Reflection: The selective absorption and reflection of light by an object can be expressed by a spectral reflectance curve. The ratio of the luminous flux reflected by the object to the luminous flux incident on the object is the relationship curve between light reflectance and wavelength. The spectral reflectance curve of an object reflects the comprehensive characteristics of that object, including its selective absorption of incident light, light scattering, and specular reflection from its surface. Figure 1 The reason why the red object shown is red is that when light from a light source reaches the object's surface, due to the object's own properties, it absorbs blue, green, and yellow light, but not red light. The unabsorbed red light is reflected back and reaches the observer, so the observer can only see the reflected red light, thus making the object appear red. This is the process by which an object exhibits its surface color.

[0034] Since the property of an object regarding color is the selective absorption of electromagnetic waves of different wavelengths, we use spectral reflectance curves to express this property. For example... Figure 2 As shown, red objects have relatively low reflectivity for short wavelengths, meaning they absorb blue and yellow light; blue objects have relatively low reflectivity for long wavelengths, meaning they absorb yellow and red light; and green objects have relatively low reflectivity for both long wavelengths (red and yellow light) and short wavelengths (blue light). For the same object, the spectral reflectivity curves are different depending on the light source reaching its surface. For example, when a blue object is illuminated by a red light source, its spectral reflectance curve is low across the entire wavelength range; when illuminated by a green light source, its spectral reflectance curve is low across the entire wavelength range; when illuminated by a blue light source, its spectral reflectance curve is high in the short wavelength range; when illuminated by a red light source, its spectral reflectance curve is low across the entire wavelength range; when illuminated by a green light source, its spectral reflectance curve is high in the mid-wavelength range; when illuminated by a blue light source, its spectral reflectance curve is low across the entire wavelength range; when illuminated by an orange light source, its spectral reflectance curve is high in the long wavelength range; when illuminated by a green light source, its spectral reflectance curve is low across the entire wavelength range; when illuminated by a blue light source, its spectral reflectance curve is low across the entire wavelength range.

[0035] Therefore, based on spectral reflectance characteristics, single-wavelength light of multiple colors is used to collect reflectance change data for each band throughout the entire bacterial growth cycle, corresponding to the color changes of the sensor. The final interpretation is then based on the data from multiple bands, providing negative or positive results. This approach addresses the limitations of single-wavelength light source detection in adapting to a wide range of reflective substrates, as well as the limitations of single-wavelength reflectance data for algorithmic interpretation.

[0036] like Figure 3As shown, the microbial culture detection unit of this embodiment includes a cavity for placing a culture container 1, and an installation space 2 for installing a light signal acquisition component is provided below the cavity. Specifically, the bottom of the culture container 1 is provided with a sensor 3 for sensing the sample state and changing color according to changes in the sample state. The light signal acquisition component includes a light source and a receiver 4. The light source is used to project light onto the sensor 3, and the receiver 4 is used to receive the reflected light after being reflected by the sensor 3.

[0037] Specifically, in this embodiment, the light source is used to project at least two different colors of single-wavelength light onto the sensor 3. The light source capable of emitting at least two different colors of single-wavelength light can be implemented in various ways. For example, the light source can be a single light source capable of directly emitting at least two different colors of single-wavelength light, such as a color-changing LED light source; the light source can also include a single light source capable of emitting white light, at least two filters capable of transmitting single-wavelength light of different colors, and a switching mechanism for controlling the filters to pass sequentially through the light source. Since white light contains all visible light bands, specific wavelengths of light can pass through the filters, thereby achieving the technical objective of emitting multiple specific colors of single-wavelength light; of course, the light source can also include at least two light-emitting units 5, each capable of emitting single-wavelength light of different colors. In this embodiment, the light source also includes two light-emitting units 5, each capable of emitting single-wavelength light of different colors. Of course, in some other preferred embodiments, the light source can be configured as a ring-shaped light source installed around the perimeter of the installation space 2, with at least two light-emitting units within the ring-shaped light source, each capable of emitting single-wavelength light of different colors. The ring-shaped light source has the advantage of convenient installation and positioning.

[0038] Specifically, at least part of the inner surface of the mounting space 2 is a rough surface used to eliminate stray light, so as to prevent stray light from interfering with the detection results. The rough surface can take various structural forms, such as a sawtooth rough surface, a threaded rough surface, or a dotted raised rough surface.

[0039] In this embodiment, the mounting space 2 includes a first mounting area 2a located below the cavity, with the light source mounted on the side wall of the first mounting area 2a. By adjusting the tilt angle of the side wall of the first mounting area 2a, the light emitted by the light source mounted on the side wall of the first mounting area 2a can be easily projected onto the sensor 3, and the reflected light after being reflected by the sensor 3 can be received by the receiver 4. In this embodiment, the inner surface of the first mounting area 2a has an inner wall size that gradually decreases from top to bottom. Specifically, the inner surface of the first mounting area 2a can be a conical surface with an inner diameter that gradually decreases from top to bottom, or it can be a square pyramidal surface with an inner wall size that gradually decreases from top to bottom. Specifically, the receiver 4 can be mounted on the bottom surface of the first mounting area 2a; alternatively, a cylindrical mounting area 2b can be provided below the first mounting area 2a, and the receiver 4 can be mounted inside the cylindrical mounting area 2b.

[0040] This embodiment also proposes a microbial culture instrument, including an incubator, which is provided with at least one microbial culture and detection unit as described above in this embodiment.

[0041] The following describes a specific implementation method for the blood culture detection system to perform detection during sample incubation, using the microbial culture detection unit of this embodiment as an example.

[0042] The blood culture detection system of this embodiment includes a microbial culture detection unit, an interpretation module, and a control module. Specifically, the microbial culture detection unit adopts the microbial culture detection unit described above in this embodiment. The interpretation module is used to obtain the interpretation result of whether the reaction sample is infected based on the reflected light signal received by the receiver. The control module is used to control the light source to alternately project single-wavelength light of different colors onto the sensor.

[0043] In some preferred embodiments, the single-wavelength light emitted by the light source can include short-wavelength light (such as blue light), long-wavelength light (such as red light), and single-wavelength light with wavelengths between short and long wavelengths (such as green light), etc. This allows the single-wavelength light of different colors emitted by the light source to cover a wider range of visible light wavelengths. Based on the principle of spectral reflectance, as the color of the sensor changes with the sample state, there will always be a single-wavelength light whose color and wavelength are close to or even equal to the color and wavelength of the reactor. Therefore, for this single-wavelength light, the sensor has a higher reflectivity, improving response sensitivity and thus increasing the accuracy of the positive rate reading. Tables 1-4 show the reflectivity data for single-wavelength light of different colors.

[0044] Table 1. Reflectance data for blue single-wavelength light

[0045]

[0046] Table 2 Reflectance data for green single-wavelength light

[0047]

[0048] Table 3. Reflectance data for orange single-wavelength light.

[0049]

[0050]

[0051] Table 4 Reflectance data for red single-wavelength light

[0052]

[0053] The data above shows that different colors of single-wavelength light have different response sensitivities to the same substrate film; for sensors in aerobic and anaerobic bottles, there is an optimal response spectrum corresponding to different color levels. During the transition from blue-violet to dark green, blue has the optimal response spectrum; during the transition from dark green to yellow, green has the optimal response spectrum. (This refers to different optimal response bands at different stages of the color change process of the sensing film).

[0054] Simultaneously, actual growth curves are collected, selecting only the data from the first 3 hours, as shown in Figure 4. From top to bottom, these represent green single-wavelength light, red single-wavelength light, and orange single-wavelength light. During interpretation in the module, the positive reporting time is first given using the curve with high response sensitivity to improve detection efficiency and ensure timely treatment for patients. Subsequently, the positive reporting results can be verified using curves of other colors of single-wavelength light to improve accuracy. In other words, multi-color single-wavelength light data can simultaneously meet the needs of timely positive reporting and accuracy, truly solving clinical pain points. Specifically, for weakly growing bacteria in clinical practice, the problems of long positive reporting times and misjudgments of positive and negative results can be effectively resolved.

[0055] In this embodiment, the interpretation module outputs a result determining whether a sample is infected based on whether the reflection signal parameter of any single wavelength light reaches a set threshold. If the reflection signal parameter of a single wavelength light reaches the set threshold, a preliminary positive interpretation result is obtained; if, during the sample culture period, the reflection signal parameters of all single wavelength lights do not reach the set threshold, a negative interpretation result is obtained. Thus, among multiple colors of single wavelength light, as long as the reflection signal parameter of any single wavelength light exceeds the set threshold, a preliminary positive interpretation result is obtained. This improves the sensitivity to weakly growing bacteria, avoids false negatives, and increases the accuracy of the positive rate interpretation. Specifically, the reflection signal parameter is a reflection signal parameter that can reflect changes in the sensor state, including but not limited to at least one of the following: intensity of the reflection signal, magnitude of reflectivity, difference in reflectivity changes, and rate of reflectivity change.

[0056] Specifically, when the interpretation module obtains a preliminary positive interpretation result, it records the preliminary positive interpretation time. The preliminary positive interpretation time is the time when the reflection signal parameter of the corresponding single wavelength light reaches a set threshold, or the preliminary positive interpretation time is the time when the interpretation module obtains the preliminary positive interpretation result based on the reflection signal parameter of the corresponding single wavelength light. The preliminary positive interpretation time provides a time reference for the verification procedure. Specifically, after the interpretation module obtains a preliminary positive interpretation result based on the reflection signal parameter of the corresponding single wavelength light, if the culture container has not been removed, the first verification procedure is initiated. In this embodiment, the set time period after the interpretation module obtains the preliminary positive interpretation result is taken as the first verification time period. During the first verification time period, the interpretation module verifies the preliminary positive interpretation result based on whether the reflection signal parameters of other single wavelength lights reach the threshold. If the interpretation module obtains a negative interpretation result based on the reflection signal parameters of all other single wavelength lights, the preliminary positive interpretation result is eliminated. If the interpretation module obtains a preliminary positive interpretation result based on the reflection signal parameter of any other single wavelength light, a positive interpretation result is obtained, and the sample verification ends. In this way, the impact of false positives caused by environmental changes on the final interpretation result can be avoided.

[0057] Furthermore, if the wavelength distribution of the single-wavelength light projected by the optical signal acquisition component to the sensor is uneven, such as consisting of longer-wavelength red light and shorter-wavelength violet light, and the first wavelength light that yields the initial positive reading is red light, it indicates that the sensor is sensitive to red light and has high reflectivity, but may have lower reflectivity for violet light. In the first verification procedure, violet light may consistently result in a negative reading due to its lower reflectivity, leading to false negatives. Therefore, to avoid false negatives in the first verification procedure due to excessive wavelength differences between other single-wavelength lights and the single-wavelength light that yields the initial positive reading, in this embodiment, if the reading module obtains a negative reading based on the reflection signal parameters of all other single-wavelength lights, the second verification procedure is initiated during the continued verification of the sample. In the second verification procedure, a second set time period following the first verification time period is designated as the second verification time period. Within this second verification time period, if a preliminary positive result is obtained again based on the reflection signal parameters of the single wavelength light from which the preliminary positive result was obtained (i.e., the same single wavelength light obtains at least two positive results), then the interpretation module obtains a positive result, and the sample verification ends. Otherwise, the sample verification continues until the end of the second verification time period. Specifically, the end of the second verification time period is the end of the verification procedure. In particular, setting the second verification time period after the first verification time period allows it to be set to a sufficiently long period after the preliminary positive result. If the preliminary positive result is a false positive due to environmental changes, since the second verification time period is sufficiently long after the preliminary positive result, the environmental change factor has been eliminated. Therefore, starting the second verification procedure within the second verification time period can also avoid false positives caused by environmental changes.

[0058] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A microbial culture and detection unit, characterized in that: The device includes a cavity for placing a culture container (1), and an installation space (2) for installing a light signal acquisition component is provided below the cavity; the bottom of the culture container (1) is provided with a sensor (3) for sensing the sample state and changing color according to the change of the sample state; the light signal acquisition component includes a light source and a receiver (4), the light source is used to project light onto the sensor (3), and the receiver (4) is used to receive the reflected light after being reflected by the sensor (3).

2. The microbial culture and detection unit according to claim 1, characterized in that: The light source is used to project at least two different colors of single wavelength light onto the sensor (3).

3. The microbial culture and detection unit according to claim 2, characterized in that: The light source is a single light source capable of emitting at least two different colors of single wavelength light; or, the light source includes a single light source capable of emitting white light and at least two filters capable of transmitting single wavelength light of different colors; or, the light source includes at least two light-emitting units (5), and different light-emitting units (5) are capable of emitting single wavelength light of different colors.

4. The microbial culture and detection unit according to claim 3, characterized in that: The light source is a ring light source installed in the installation space and surrounding the entire ring. The ring light source is provided with at least two light-emitting units (5), and different light-emitting units (5) can emit single wavelength light of different colors.

5. The microbial culture and detection unit according to claim 1, characterized in that: The mounting space (2) has at least a portion of its inner surface as a rough surface for eliminating stray light.

6. The microbial culture and detection unit according to claim 5, characterized in that: The rough surface is a sawtooth rough surface, a threaded rough surface, or a dotted raised rough surface.

7. The microbial culture and detection unit according to any one of claims 1-6, characterized in that: The installation space (2) includes a first installation area (2a) located below the cavity, and the light source is installed on the side wall of the first installation area (2a).

8. The microbial culture and detection unit according to claim 7, characterized in that: The receiver (4) is installed on the bottom surface of the first mounting area (2a); or, a cylindrical mounting area (2b) is provided below the first mounting area (2a), and the receiver (4) is installed in the cylindrical mounting area (2b).

9. The microbial culture and detection unit according to claim 7, characterized in that: The inner surface of the first mounting area (2a) is a conical or square conical surface with an inner wall size that gradually decreases from top to bottom.

10. A microbial culture apparatus, comprising an incubator, characterized in that: The incubator is equipped with at least one microbial culture and detection unit as described in any one of claims 1-9.

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