JP2011141183A - Microorganism number measurement apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further enhance measurement accuracy about a microorganism number measurement. <P>SOLUTION: To achieve the purpose, an agitator 4 agitates a measurement liquid 2 at a first rotation number in suspended state. After conductivity change by a conductivity change determination part 21 becomes smaller than a predetermined value, the agitator 4 agitates the measurement liquid 2 at a second rotation number lower than the first rotation number. In the state, a microorganism number calculation part 16 calculates the number of the microorganism. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a microorganism count measuring apparatus.

  A conventional microorganism count measuring apparatus has the following configuration.

  That is, a measurement container in which the measurement electrode and the stirrer are placed in an immersion state in the internal measurement solution, a rotation driving means for rotationally driving the stirrer from the outside of the measurement container, and a collection signal to the measurement electrode A collection signal generation unit for supplying, a measurement signal generation unit for supplying a measurement signal to the measurement electrode, an impedance measurement unit for measuring the impedance of the measurement liquid, and a microorganism count calculation unit connected to the impedance measurement unit; It was the composition with.

  That is, the number of microorganisms is calculated by the microorganism number calculation unit based on the impedance measured by the impedance measurement unit (for example, Patent Document 1 below).

JP 2009-207431 A

  The problem in the above conventional example is to further increase the measurement accuracy.

  That is, in this microorganism count measuring device, when trying to measure the number of microorganisms (bacteria) in the oral cavity, for example, the saliva in the oral cavity is collected with a collecting tool such as a cotton swab and eluted into the measurement liquid. In this state, the number of microorganisms is measured, but the state (time) of elution in the measurement solution varies greatly depending on the condition in the oral cavity. In this case, the measurement accuracy varies.

  Accordingly, the present invention aims to further increase the measurement accuracy.

  In order to achieve this object, the present invention provides a measurement container in which a measurement electrode and a stirring body are immersed in an internal measurement solution, and a rotational drive that rotates the stirring body from the outside of the measurement container. Means, a collection signal generation unit that supplies a collection signal to the measurement electrode, a measurement signal generation unit that supplies a measurement signal to the measurement electrode, an impedance measurement unit that measures the impedance of the measurement solution, and the impedance A microorganism number calculation unit connected to the measurement unit; a solution conductivity calculation unit connected to the impedance measurement unit; and a conductivity change determination unit connected to the solution conductivity calculation unit; Then, after the measurement liquid is stirred in a suspended state at the first rotational speed, and the change in conductivity by the conductivity change determining unit becomes smaller than a predetermined value, the stirring body causes the change from the first rotational speed. Low In the second speed to stir the test solution, by the microbial count calculating portion in this state, a configuration of calculating the number of microorganisms, thereby it is to achieve the intended purpose.

  As described above, the present invention includes a measurement container in which a measurement electrode and a stirring body are immersed in an internal measurement liquid, a rotation driving unit that rotationally drives the stirring body from the outside of the measurement container, and the measurement A collection signal generation unit that supplies a collection signal to the electrode, a measurement signal generation unit that supplies a measurement signal to the measurement electrode, an impedance measurement unit that measures the impedance of the measurement liquid, and the impedance measurement unit A microorganism conductivity calculator, a solution conductivity calculator connected to the impedance measurement unit, and a conductivity change determination unit connected to the solution conductivity calculator. The suspension is stirred in a suspended state at a rotation number of 1, and after the change in conductivity by the conductivity change determination unit becomes smaller than a predetermined value, a second lower than the first rotation number is caused by the stirring body. The number of revolutions Liquid is stirred, by the microbial count calculating unit in this state, since it is obtained by a configuration of calculating the number of microorganisms, it is possible to further increase the measurement accuracy.

  That is, in the present invention, the stirring liquid is stirred in a suspended state at the first rotational speed by the stirring body, and the conductivity change by the conductivity change determination unit is smaller than a predetermined value, that is, It is determined that most of the microorganisms are eluted in the measurement liquid by the change in conductivity of the measurement liquid being smaller than a predetermined value, and after this determination, the second lower than the first rotation speed is determined by the stirrer. The measurement liquid is stirred at the number of rotations of the sample, and the eluted microorganisms are collected on the measurement electrode, whereby the number of microorganisms is calculated by the microorganism number calculation unit, so that the measurement accuracy can be further improved. Is.

Control block diagram of one embodiment of the present invention Operation flowchart Characteristic diagram showing its operating state Characteristic diagram showing comparison between this embodiment and conventional example

(Embodiment 1)
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  In FIG. 1, reference numeral 1 denotes a cylindrical measurement container having an open top surface, and a measurement electrode 3 and a stirring body 4 are disposed in a measurement solution (pure water) 2 placed in the immersion state.

  Note that the measurement electrode 3 is formed by disposing comb-like electrodes facing each other at a predetermined interval, as in Patent Document 1. Further, a sampling part 6 of the sampling tool 5 is inserted into the measurement liquid 2 from the upper surface opening of the measurement container 1.

  The collection tool 5 is for collecting microorganisms by inserting the collection part 6 into, for example, the oral cavity and attaching saliva, and as shown in FIG. Thus, the collected microorganisms are eluted in the measurement liquid 2 by receiving the rotational force and the collision force by the stirring member 4.

  The measurement electrode 3 includes a collection signal generation unit 7 for supplying a collection signal to the measurement electrode 3 and a measurement signal generation unit 8 for supplying a measurement signal to the measurement electrode 3. Are connected via an output amplifier 10. That is, for example, 3 MHz is added from the collected signal generation unit 7, and 800 kHz is added from the measurement signal generation unit 8, for example, by the adder 9, which is supplied to the measurement electrode 3 via the output amplifier 10.

  The measurement electrode 3 is connected to a microorganism count calculation unit 16 via an I / V amplifier 11, a gain switching amplifier 12, an A / D converter 13, an impedance measurement unit 14, and an impedance change detection unit 15. . Note that a low-pass filter (not shown) is interposed between the I / V amplifier 11 and the gain switching amplifier 12, and only the 800 kHz signal is output to the impedance measuring unit 14. ing.

  In addition, a solution conductivity calculation unit 17 is connected to the impedance measurement unit 14, and a storage unit 18 is connected to the solution conductivity calculation unit 17.

  Output from the storage unit 18 is performed in two directions, one of which is output to the conductivity change amount calculation unit 19 and the conductivity change rate calculation unit 20. The output of the conductivity change amount calculation unit 19 is output to the conductivity change rate calculation unit 20, and the output of the conductivity change rate calculation unit 20 is output to the conductivity change determination unit 21. .

  The other output of the storage unit 18 is output to the drift correction unit 22 of the microorganism count calculation unit 16.

  The conductivity change determination unit 21 is output to the motor control unit 23, and the output of the motor control unit 23 is output to the motor drive unit 24. The motor drive unit 24 rotates the magnet plate 26 attached to the motor 25, and rotates the stirrer 4 by a plurality of magnets (not shown) provided on the magnet plate 26.

  On the other hand, the microorganism count calculation section 16 calculates the number of microorganisms by the microorganism count conversion section 27 after performing drift correction by the drift correction section 22, and is a correlation table connected to the microorganism count calculation section 16. 28 is used for conversion of the number of microorganisms. The number of microorganisms calculated by the microorganism number conversion unit 27 of the microorganism number calculation unit 16 is displayed on the display unit 29.

  In the above configuration, FIG. 2 shows a control flow.

  First, the process starts at S1 in FIG. At this time, the motor control unit 23 rotationally drives the motor 25 at 3000 rpm, whereby the stirring member 4 is also rotated at 3000 rpm. Due to the strong rotation of the stirrer 4, the measurement liquid 2 is given a strong rotational turning force, and the sampling unit 6 is also subjected to a strong rotational force, and the collision force of the stirrer 4 is applied. Therefore, microorganisms are gradually eluted in the measuring solution 2 (S2).

  In S2 of FIG. 2, the conductivity of the measurement liquid 2 is measured by S3 in a state where the suspension is performed for 50 seconds. This is performed by measuring the impedance between the measurement electrodes 3 with the impedance measurement unit 14 and measuring the solution conductivity with the solution conductivity calculation unit 17 based on the measurement. The solution conductivity at this time is stored in the storage unit 18 (n-1 times portion in FIG. 3b).

  In addition, since the stirrer 4 is driven at a strong rotational speed of, for example, 3000 rpm, the bacteria eluted from the collection unit 6 cannot remain in the measurement electrode 3 part. 3 measures the electrical conductivity of the measurement liquid 2. Of course, as shown in FIG. 3 (b), as shown in FIG. 3 (a), when the microorganisms are eluted in the measurement liquid 2, the solution conductivity is accordingly increased as shown in FIG. 3 (b). Will rise in the same way.

  Next, in S4 of FIG. 2, the suspension is further performed for 10 seconds, and then the solution conductivity is measured in S5.

  In S6 of FIG. 2, the solution conductivity in S3 and the solution conductivity in S5 stored in the storage unit 18 are supplied to the conductivity change amount calculation unit 19, and the solution conductivity in S3 and the solution conductivity in S5 are The amount of change in solution conductivity that is the difference between the two is calculated.

  Next, in S7 of FIG. 2, the solution conductivity change amount calculated by the conductivity change amount calculation unit 19 and the solution conductivity in S5 are supplied to the conductivity change rate calculation unit 20, and the solution with respect to the solution conductivity of S5 is supplied. Calculate the rate of change of conductivity change.

  Further, in S8 of FIG. 2, the conductivity change rate calculated by the conductivity change rate calculating unit 20 is supplied to the conductivity change determining unit 21, and it is determined whether or not the change rate is smaller than 5%.

  If the change rate is greater than 5% based on the determination result, it is determined that the elution state of the microorganism is still unstable, and the process returns to between S3 and S4 again.

  If it is determined in S8 that the rate of change is smaller than 5%, in S9, the motor control unit 23 reduces the rotational speed of the motor 25 to 1200 rpm. In this state, the microorganisms eluted in the measurement liquid 2 are collected between the measurement electrodes 3 by dielectrophoresis, so that a capacitance value corresponding to the amount of the microorganisms can be obtained (S10).

  Since this capacitance value is a change in impedance, it is measured by the impedance measurement unit 14, and then the impedance change amount is obtained by the impedance change detection unit 15. The slope state of this impedance change and the correlation table 28 are obtained. The number of microorganisms is calculated from the data provided in.

  4 (a) and 4 (b) show the relationship between the bacterial elution amount and the capacitance in the present embodiment, and the slope of capacitance is stable in both the solid line state and the broken line state shown in FIG. 4 (a). It is understood that

  That is, the solid line in FIG. 4A indicates a state where the suspension is late, that is, the number of returns from S8 to S4 in FIG. 2 is large. Further, the broken line in FIG. 4A indicates that the suspension is completed quickly, that is, the number of return from S8 to S4 in FIG. 2 is small.

  In this embodiment, as described above, since the gradient state of the capacitance is stable regardless of whether the suspension is completed early or late, as a conclusion, the measurement accuracy for the microorganism count in the microorganism count calculator 16 can be further increased. Is.

  On the other hand, FIG. 4C shows a conventional example, and the solid line in FIG. Moreover, the broken line of FIG.4 (c) is a case where suspension completion is early.

  Conventionally, as shown in FIG. 4 (c), the suspension completion is set to a constant value regardless of whether the suspension is late or early. In FIG. 4 (c), the suspension is not yet completed. As shown by the solid line in FIG. 4D, the inclined state is smaller than the broken line. That is, as shown in FIG. 4D, the variation in the inclination state of the capacitance leads to the fact that the measurement accuracy cannot be increased.

  Since drift is also present in the tilted state obtained by the impedance change detection unit 15 (for example, as shown in FIG. 4B), this drift correction needs to be performed. In the present embodiment, the storage unit 18 uses the stored solution conductivity at the time of suspension completion in FIG. 4A to drift-correct the tilt state of the impedance change detection unit 15 with the drift correction unit 22, The number of microorganisms is converted by the microorganism number conversion unit 27 from the corrected inclination state and the value of the correlation table 28, and the value is displayed on the display unit 29, for example, “2.5E + 06 CFU / ml” (2.5 X10 6th power CFU / ml: CFU represents the number of microorganisms capable of forming colonies.

  As described above, the present invention includes a measurement container in which a measurement electrode and a stirring body are immersed in an internal measurement liquid, a rotation driving unit that rotationally drives the stirring body from the outside of the measurement container, and the measurement A collection signal generation unit that supplies a collection signal to the electrode, a measurement signal generation unit that supplies a measurement signal to the measurement electrode, an impedance measurement unit that measures the impedance of the measurement liquid, and the impedance measurement unit A microorganism conductivity calculator, a solution conductivity calculator connected to the impedance measurement unit, and a conductivity change determination unit connected to the solution conductivity calculator. The suspension is stirred in a suspended state at a rotation number of 1, and after the change in conductivity by the conductivity change determination unit becomes smaller than a predetermined value, a second lower than the first rotation number is caused by the stirring body. The number of revolutions Liquid is stirred, by the microbial count calculating unit in this state, since it is obtained by a configuration of calculating the number of microorganisms, it is possible to further increase the measurement accuracy.

  That is, in the present invention, the stirring liquid is stirred in a suspended state at the first rotational speed by the stirring body, and the conductivity change by the conductivity change determination unit is smaller than a predetermined value, that is, It is determined that most of the microorganisms are eluted in the measurement liquid by the change in conductivity of the measurement liquid being smaller than a predetermined value, and after this determination, the second lower than the first rotation speed is determined by the stirrer. The measurement liquid is stirred at the number of rotations of the sample, and the eluted microorganisms are collected on the measurement electrode, whereby the number of microorganisms is calculated by the microorganism number calculation unit, so that the measurement accuracy can be further improved. Is.

  Therefore, it is expected to be widely used as a microorganism count measuring device.

DESCRIPTION OF SYMBOLS 1 Measuring container 2 Measuring liquid 3 Measuring electrode 4 Stirring body 5 Sampling tool 6 Sampling part 7 Bacteria collection signal generation part 8 Measurement signal generation part 9 Adder 10 Output amplifier 11 I / V amplifier 12 Gain switching amplifier 13 A / D converter 14 Impedance measurement unit 15 Impedance change detection unit 16 Microorganism count calculation unit 17 Solution conductivity calculation unit 18 Storage unit 19 Conductivity change amount calculation unit 20 Conductivity change rate calculation unit 21 Conductivity change determination unit 22 Drift correction unit 23 Motor control unit 24 Motor Drive Unit 25 Motor 26 Magnet Plate 27 Microorganism Count Conversion Unit 28 Correlation Table 29 Display Unit

Claims (2)

In the internal measurement liquid, a measurement container in which the measurement electrode and the stirring member are placed in an immersed state,
From the outside of the measurement container, rotation driving means for rotating the stirring body,
A collected signal generation unit for supplying a collected signal to the measurement electrode;
A measurement signal generator for supplying a measurement signal to the measurement electrode;
An impedance measuring unit for measuring the impedance of the measuring solution;
A microorganism count calculator connected to the impedance measuring unit;
A solution conductivity calculator connected to the impedance measuring unit;
A conductivity change determination unit connected to the solution conductivity calculation unit;
The measurement liquid is stirred in a suspended state at the first rotation speed by the stirring body, and after the change in conductivity by the conductivity change determination unit becomes smaller than a predetermined value, the first stirring is performed by the stirring body. The microorganism count measuring apparatus configured to agitate the measurement liquid at a second rotation speed lower than the rotation speed of the first and calculate the number of microorganisms by the microorganism count calculation section in this state. A storage unit is connected to the output side of the solution conductivity calculation unit, and a first output of the storage unit is output to the conductivity change amount calculation unit and the conductivity change rate calculation unit, and the conductivity change amount calculation unit The output is output to the conductivity change rate calculation unit, the output of the conductivity change rate calculation unit is output to the conductivity change determination unit, the output of the conductivity change determination unit is output to the rotation drive means, The microorganism count measuring apparatus according to claim 1, wherein the second output of the storage unit is configured to be output to the microorganism count calculating unit.

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