JPWO2020026353A1 - Mass spectrometer, mass spectrometry method and mass spectrometry program - Google Patents

Abstract

Analysis data is acquired by the data acquisition unit for each of the plurality of samples. Multiple samples are classified into multiple basic groups by the classification department, and a phylogenetic tree is created by the phylogenetic tree creation department based on the similarity of drug resistance patterns including resistance to multiple specific drugs for the multiple basic groups. .. One of the multiple nodes in the phylogenetic tree is designated as the node of interest. A plurality of basic groups belonging to a plurality of child nodes for the node of interest are reorganized into a plurality of reorganization groups corresponding to the plurality of child nodes by the reorganization unit. By analyzing the difference in the analysis data among the plurality of reorganization groups, the analysis unit searches for a marker peak for determining the resistance to the drug corresponding to the node of interest.

Description

The present invention relates to a mass spectrometer, a mass spectrometry method and a mass spectrometry program for analyzing analytical data of a sample.

A mass spectrometer is used to identify samples of various microorganisms and the like. By comparing a plurality of mass spectra obtained for a plurality of samples, a peak that serves as an index for identifying each sample can be detected. In recent years, a microbial identification system by MALDI-MS (matrix-assisted laser desorption / ionization mass spectrometry) has rapidly become widespread (see, for example, Non-Patent Document 1). Non-Patent Document 1 contains a paper entitled "Bacterial Analysis by MALDI-MS". The MALDI-MS system in clinical practice is mainly used for identification of bacterial species.

Kanae Teramoto, "Bacterial Analysis by MALDI-MS", Shimadzu Criticism, September 2017, Vol. 74, Nos. 1 and 2, p. 51-62

In the future, it is desired to determine not only the bacterial species but also the presence or absence of drug resistance by a mass spectrometer. For that purpose, it is necessary to search for biomarkers that contribute to the determination of the presence or absence of drug resistance from a sample of microorganisms.

In order to search for the peak corresponding to the biomarker in the mass spectrum, for example, the following method can be considered. A plurality of samples are classified into a group of samples having drug resistance and a group of samples having no drug resistance, and a mass spectrum of each sample is obtained by a mass spectrometer. By comparing the mass spectra of the samples between the two groups, peaks with significant differences between the two groups are detected. The detected peak is used as a marker peak for determining the presence or absence of drug resistance.

When the number of groups and the number of drugs are small, it is easy to search for marker peaks from the mass spectrum. However, when the number of groups and the number of drugs are large, it is not efficient to search for marker peaks for many combinations of groups and drugs. A similar problem arises when searching for a marker peak for determining the presence or absence of a specific gene, not limited to the presence or absence of resistance to a specific drug.

An object of the present invention is to provide a mass spectrometer, a mass spectrometry method, and a mass spectrometry program capable of efficiently searching for a marker peak for determining resistance to a desired drug.

(1) The mass spectrometer according to one aspect of the present invention is a mass spectrometer that can be connected to a display unit, and is a data acquisition unit that acquires analysis data for each of a plurality of samples, and a plurality of basic samples. A phylogenetic tree creation unit that creates a phylogenetic tree containing multiple nodes based on the similarity of drug resistance patterns that include resistance to multiple specific drugs for multiple basic groups, and a phylogenetic tree creation unit that classifies them into groups. A display control unit that displays the specified phylogenetic tree on the display unit, a node reception unit that accepts the designation of one of a plurality of nodes as the designation of the node of interest, and a plurality of nodes of interest specified in the phylogenetic tree. Corresponds to each of the reorganization unit that generates multiple reorganization groups by reorganizing multiple basic groups belonging to the child nodes into multiple groups corresponding to each of the multiple child nodes, and each of the plurality of reorganization groups. Analysis to search for marker peaks for determining resistance to a drug corresponding to a specified node of interest by analyzing differences in analytical data among multiple reorganization groups based on one or more analytical data. It has a part.

In this mass spectrometer, analytical data is acquired for each of a plurality of samples. In addition, multiple samples are classified into multiple basic groups, and a phylogenetic tree containing multiple nodes is created based on the similarity of drug resistance patterns including resistance to multiple specific drugs for the multiple basic groups. .. The created phylogenetic tree is displayed on the display unit, and the designation of any node among the plurality of nodes is accepted as the designation of the node of interest.

A plurality of reorganization groups are generated by reorganizing a plurality of basic groups belonging to a plurality of child nodes for the node of interest specified in the phylogenetic tree into a plurality of groups corresponding to the plurality of child nodes. Resistance to the drug corresponding to the specified node of interest by analyzing the differences in the analytical data among the multiple reorganization groups based on one or more analysis data corresponding to each of the multiple reorganization groups. The marker peak for determining is searched.

According to this configuration, the user can easily specify the node corresponding to the desired drug in the phylogenetic tree displayed on the display unit as the node of interest even when the number of groups and the number of drugs are large. Further, the user does not need to perform an operation for reconstructing a plurality of groups belonging to the node of interest into one or more groups belonging to each of the plurality of child nodes. This makes it possible to efficiently search for a marker peak for determining resistance to a desired drug.

(2) Each time the node reception unit accepts the designation of the node of interest, the reorganization unit creates a plurality of basic groups belonging to a plurality of child nodes of the specified node of interest, each of which corresponds to a plurality of child nodes. Multiple reorganization groups are generated by reorganizing into groups of, and the analysis unit corresponds to each of the generated reorganization groups each time a plurality of reorganization groups are generated by the reorganization unit. By analyzing the difference in the analysis data among a plurality of reorganization groups based on one or more analysis data, a marker peak for determining the resistance to the drug corresponding to the specified node of interest is searched for. May be good.

In this case, the user can recursively repeat the designation of the node of interest. This makes it possible to efficiently search for a plurality of marker peaks for determining resistance to a plurality of desired drugs.

(3) The display control unit may display information indicating the searched marker peak on the display unit. In this case, the user can easily recognize the information indicating the searched marker peak by visually recognizing the display unit.

(4) The display control unit may display a plurality of reorganization groups on the display unit. In this case, the user can easily recognize the reorganization group by visually recognizing the display unit.

(5) The plurality of analysis data are a plurality of mass spectrum data, the plurality of mass spectrum data includes the mass-to-charge ratio and the detection intensity for the plurality of peaks, and the analysis unit includes a plurality of mass spectrum data acquired by the data acquisition unit. A peak list creation unit that creates a peak list for each sample showing the mass-to-charge ratio of multiple peaks and the detection intensity of each peak based on mass spectrum data, and multiple peak lists and multiple re-lists for multiple samples. Multiple mass-to-charge ratios arranged in the first direction and multiple reorganization group samples arranged in the second direction and multiple mass-to-charge ratios and multiple samples corresponding to the multiple samples based on the knitting group. Marker peaks are obtained by analyzing the differences between multiple reorganization groups based on the multiple detection intensities corresponding to each mass-to-charge ratio of the peak matrix and the peak matrix creation unit that creates the peak matrix including the detection intensities of. It may include a search unit to search. In this case, it is possible to efficiently search for a marker peak for determining the presence or absence of resistance to a predetermined drug in a mass spectrum based on a plurality of mass spectrum data.

(6) The search unit may search for the marker peak corresponding to the designated node of interest by univariate analysis of a plurality of detection intensities corresponding to each mass-to-charge ratio of the peak matrix. In this case, the difference in mass spectrum data among the plurality of reorganization groups can be easily analyzed.

(7) Resistance to a plurality of specific drugs may include the presence or absence of resistance to a plurality of drugs. In this case, a marker peak for determining the presence or absence of a predetermined drug resistance can be efficiently searched.

(8) The pattern of drug resistance may include genetic information, and resistance to a plurality of specific drugs may include a plurality of gene types. In this case, a marker peak for determining the presence or absence of a predetermined gene such as a drug resistance gene can be efficiently searched.

(9) The mass spectrometer further includes a storage device for storing analysis data for each of a plurality of samples, an operation unit operated by the user, and a display unit, and a plurality of data acquisition units are provided from the storage device. The analysis data may be acquired, the display control unit may display the created phylogenetic tree on the display unit, and the analysis unit may search for the marker peak based on the operation of the operation unit by the user.

In this case, the data acquisition unit acquires analysis data for each of the plurality of samples stored in the storage device. In addition, the phylogenetic tree created by the phylogenetic tree creation unit is displayed on the display unit by the display control unit. The marker peak is searched by the analysis unit based on the operation of the operation unit by the user. This makes it possible to efficiently search for a marker peak for determining resistance to a desired drug.

(10) The mass spectrometric method according to another aspect of the present invention is a mass spectrometric method using a display unit, in which a step of acquiring analysis data for each of a plurality of samples and a plurality of samples are divided into a plurality of basic groups. View the steps to create a phylogenetic tree containing multiple nodes and the created phylogenetic tree based on the similarity of the classification steps and the pattern of drug resistance, including resistance to multiple specific drugs for multiple basic groups. A step to display in the unit, a step to accept the designation of one of a plurality of nodes as the designation of the node of interest, and a plurality of basic groups belonging to a plurality of child nodes of the node of interest specified in the phylogenetic tree. Multiple reorganization groups are generated by reorganizing into multiple groups, each corresponding to multiple child nodes, and multiple reorganization groups based on one or more analytical data corresponding to each of the multiple reorganization groups. It includes a step of searching for a marker peak for determining resistance to a drug corresponding to a designated node of interest by analyzing differences in analytical data between reorganization groups.

According to this mass spectrometry method, the user can easily specify the node corresponding to the desired drug in the phylogenetic tree displayed on the display as the node of interest even when the number of groups and the number of drugs are large. can. Further, the user does not need to perform an operation for reconstructing a plurality of groups belonging to the node of interest into one or more groups belonging to each of the plurality of child nodes. This makes it possible to efficiently search for a marker peak for determining resistance to a desired drug.

(11) The mass spectrometric program according to still another aspect of the present invention is a mass spectrometric program that can be executed by a processing device connected to a display unit, and includes a process of acquiring analysis data for each of a plurality of samples and a plurality of processes. A process of classifying a sample into multiple basic groups and a process of creating a phylogenetic tree containing multiple nodes based on the similarity of drug resistance patterns including resistance to multiple specific drugs for multiple basic groups. , The process of displaying the created phylogenetic tree on the display, the process of accepting the designation of one of the multiple nodes as the designation of the node of interest, and the multiple child nodes of the node of interest specified in the phylogenetic tree. A process of generating a plurality of reorganization groups by reorganizing a plurality of basic groups belonging to a plurality of basic groups into a plurality of groups corresponding to a plurality of child nodes, and one or a plurality of groups corresponding to each of the plurality of reorganization groups. A process of searching for a marker peak for determining resistance to a drug corresponding to a specified node of interest by analyzing the difference in the analysis data among a plurality of reorganization groups based on the analysis data. Let the device do it.

According to this mass spectrometry program, the user can easily specify the node corresponding to the desired drug in the phylogenetic tree displayed on the display as the node of interest even when the number of groups and the number of drugs are large. can. Further, the user does not need to perform an operation for reconstructing a plurality of groups belonging to the node of interest into one or more groups belonging to each of the plurality of child nodes. This makes it possible to efficiently search for a marker peak for determining resistance to a desired drug.

According to the present invention, it is possible to efficiently search for a marker peak for determining resistance to a predetermined drug.

FIG. 1 is a diagram showing a configuration of a mass spectrometer according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of a group reception screen. FIG. 3 is a diagram showing an example of a peak matrix. FIG. 4 is a diagram showing an example of the characteristic reception screen. FIG. 5 is a diagram showing an example of the created phylogenetic tree. FIG. 6 is a diagram showing groups before and after reorganization. FIG. 7 is a diagram showing a configuration of a data analysis device. FIG. 8 is a flowchart showing an algorithm of mass spectrometry processing performed by the mass spectrometry program. FIG. 9 is a flowchart showing an algorithm of mass spectrometry processing performed by the mass spectrometry program.

(1) Configuration of Mass Spectrometer The following, the mass spectrometer, the mass spectrometry method, and the mass spectrometry program according to the embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of a mass spectrometer according to an embodiment of the present invention. FIG. 1 mainly shows the hardware configuration of the mass spectrometer 1. As shown in FIG. 1, the mass spectrometer 1 includes an analysis unit 3 and a processing device 10.

The analysis unit 3 uses MALDI (matrix-assisted laser desorption / ionization method) to generate mass spectrum data showing the mass spectra of various samples such as microorganisms. A plurality of samples are classified into a plurality of groups based on a predetermined characteristic. Here, characteristic information including a plurality of characteristic elements is used to specify a predetermined characteristic. In the present embodiment, the plurality of characteristic elements are the presence or absence of resistance to a plurality of drugs, and the characteristic information is a pattern of drug resistance (combination of the presence or absence of resistance to a plurality of drugs).

For example, N _S samples in one of the groups different pattern N _G number of drug resistance is prepared. Further, the N _S mass spectrum data corresponding respectively to the N _S samples are generated. N _G and _{N S} are each a natural number of 2 or more, _{N S} is greater than _{N G.} The characteristic information of the group is not limited to the combination of the presence or absence of resistance to a plurality of drugs, and may be genetic information or the like. For example, a plurality of characteristic elements included in genetic information are a plurality of genes.

Hereinafter, the initial _NG group is referred to as a basic group. Further, a group obtained by reorganizing a basic group by a method described later is called a reorganization group. Both the basic group and the reorganized group are collectively referred to as groups.

The processing device 10 includes a CPU (central processing unit) 11, a RAM (random access memory) 12, a ROM (read-only memory) 13, a storage device 14, an operation unit 15, a display unit 16, and an input / output I / F (interface). It is composed of 17. The CPU 11, RAM 12, ROM 13, storage device 14, operation unit 15, display unit 16, and input / output I / F 17 are connected to the bus 18. The CPU 11, the RAM 12, and the ROM 13 constitute the data analysis device 2.

The RAM 12 is used as a work area of the CPU 11. The system program is stored in the ROM 13. The storage device 14 includes a storage medium such as a hard disk or a semiconductor memory, and stores a mass spectrometry program. When the CPU 11 executes the mass spectrometry program stored in the storage device 14 on the RAM 12, the mass spectrometry processing described later is performed. Further, the storage device 14 stores the mass spectrum data of the sample generated by the analysis unit 3.

The operation unit 15 is an input device such as a keyboard, a mouse, or a touch panel. The display unit 16 is a display device such as a liquid crystal display device. The user can give various instructions to the data analysis device 2 by using the operation unit 15. The display unit 16 can display an image showing the analysis result by the data analysis device 2. The input / output I / F 17 is connected to the analysis unit 3.

The data analysis device 2 searches for a marker peak for determining an arbitrary characteristic element. In the present embodiment, the data analysis device 2 searches for a marker peak for determining the presence or absence of resistance to an arbitrary drug as an arbitrary characteristic element. Hereinafter, the operation of the data analysis device 2 will be described.

(2) Search for Marker Peak A group reception screen for receiving an instruction for creating a basic group and an instruction for classifying a sample into the created basic group is displayed on the display unit 16. The user can give an instruction to create a basic group on the group reception screen using the operation unit 15 and an instruction to classify the sample into the created basic group to the data analysis device 2. Each basic group belongs to one or more samples.

FIG. 2 is a diagram showing an example of a group reception screen. As shown in FIG. 2, the group reception screen 20 includes a group column 21, a sample column 22, a group addition button 23, a group deletion button 24, a sample addition button 25, a sample deletion button 26, and a decision button 27. In the group column 21, a list of group names assigned to the created basic group (in the example of FIG. 2, "Group01", "Group02", ..., "Group06") is displayed.

The user can add a new basic group by inputting a desired group name in the group field 21 and operating the group addition button 23, and the user can add any of the group fields 21. By designating the group name and operating the group delete button 24, the basic group having the designated group name can be deleted.

In the sample column 22, a list of sample names given to the samples belonging to the basic group to which the group name is specified in the group column 21 (in the example of FIG. 2, "Sample 01-1", "Sample 01-2", …, “Sample 02-1”) is displayed. Further, in the sample column 22, a list of data names assigned to the mass spectrum data corresponding to the sample names (in the example of FIG. 2, "Sample_01-1.txt", "Sample_01-2.txt", ..., " Sample_02-1.txt ") is displayed. By operating the scroll bar in the sample column 22, other sample names and data names can be displayed in the sample column 22.

The user specifies a basic group in the group field 21, inputs the sample name given to the desired sample in the designated sample field 22, and operates the sample addition button 25 to add a new basic group to the designated basic group. Samples can be added.

The user specifies the basic group in the group column 21, specifies one of the sample names in the sample column 22, and operates the sample delete button 26 to specify the sample corresponding to the specified sample name. Can be deleted from the basic group. By operating the enter button 27, the basic groups of a plurality of samples are confirmed.

Based on the mass spectrum data, a peak list including a set of the mass-to-charge ratio (m / z) of a plurality of peaks in the mass spectrum and the detection intensity of each peak is created for each sample. Accordingly, in the present embodiment, the N _S peak list corresponding to the N _S samples are created. The the N _S peak list includes N _P-number of mass-to-charge ratio excluding duplicate a mass to charge ratio. N _P number is a natural number of 2 or more. Further, based on the peak list and a plurality of basic groups, the peak matrix indicating a relationship between each and the N _S detected intensity of N _P number of mass-to-charge ratio is created. The created peak matrix is displayed on the display unit 16. Analysis of mass spectrum differences between multiple basic groups is performed based on the peak matrix. Similarly, a peak matrix is created based on the peak list and a plurality of reorganization groups described later, and the difference in mass spectrum among the plurality of reorganization groups is analyzed based on the created peak matrix.

FIG. 3 is a diagram showing an example of a peak matrix. As shown in FIG. 3, the peak matrix has the form of a row number N _P × number of columns N _S. N _P-number of mass-to-charge ratio included in the N _S peak list is assigned respectively to the N _P rows of peaks matrix. In the example of FIG. 3, the mass-to-charge ratios are arranged in ascending order. Further, a plurality of groups (basic group or reorganize groups) to the classified the N _S samples identifier is assigned respectively to the N _S columns of peaks matrix. The arrangement of rows and columns may be reversed. Each element of the peak matrix is assigned a detection intensity at the corresponding sample and at the corresponding mass-to-charge ratio. The detection intensity of any element of the peak matrix may be zero.

Under the null hypothesis that the difference between the groups are present, univariate analysis is performed on the N _S detected intensity for each row of peaks matrix created. As the univariate analysis, a statistical hypothesis test such as the t-test or the Mann-Whitney U test is used, and when the number of groups is 3 or more, analysis of variance (ANOVA) or the like is used. As a result of the univariate analysis, a p-value indicating the statistical reliability of the differences between the groups is calculated row by row.

The p-value in each row is compared to a predetermined significance level α. The significance level α may be, for example, 0.05 or 0.01. As a result of comparison between the p-value and the significance level α, the mass-to-charge ratio of the rows whose p-value is smaller than the significance level α, that is, the rows having a significant difference between the groups is specified. The peak corresponding to the specified mass-to-charge ratio is specified as a marker peak. The analysis result showing the specified mass-to-charge ratio and marker peak is displayed on the display unit 16.

(3) Group Reorganization In the present embodiment, the plurality of basic groups created in FIG. 2 can be reorganized into a small number (for example, two) reorganization groups based on arbitrary characteristics. In this embodiment, a plurality of basic groups can be reorganized into a small number of reorganization groups based on the pattern of drug resistance. Also, the reorganization group can be reorganized into another reorganization group. This makes it possible to search for a marker peak that determines the presence or absence of resistance to one or a small number of drugs. The method will be described below.

A characteristic reception screen for setting characteristic elements in a plurality of basic groups is displayed on the display unit 16. FIG. 4 is a diagram showing an example of the characteristic reception screen. As shown in FIG. 4, characteristic acceptance screen 30 is a table having the form of a row number N _G × number of columns N _D, shows the relationship between the basic group and the characteristic element. In the present embodiment, characteristic information, a pattern of drug resistance, in particular a combination of the presence or absence of resistance to the N _D drugs. The characteristic factor is the presence or absence of resistance to each drug. The N _G rows characteristics reception screen 30, N _G number of basic groups are allocated. The N _D columns of characteristic reception screen 30, the N _D drug is assigned. N _D is a natural number of 2 or more.

The user, using the operation unit 15, to each of the N _D columns for each row "+" sign or a "-" by entering a symbol, and sets the pattern of drug resistance for each Basic Group be able to. The "+" symbol means that the basic group has resistance to the corresponding drug. The "-" symbol means that the basic group is not resistant to the corresponding drug. A pattern of drug resistance is set for each of the _{NG basic groups.} In the present embodiment, the user sets the drug resistance pattern for a plurality of basic groups, but the relationship between the plurality of basic groups and the drug resistance pattern may be stored in advance.

In the _NG basic group, the similarity of drug resistance patterns is different. The similarity between multiple basic groups is represented by a phylogenetic tree (dendrogram). The phylogenetic tree is represented as a result of hierarchical cluster analysis.

FIG. 5 is a diagram showing an example of a phylogenetic tree showing the relationship of similarity between a plurality of basic groups for a pattern of drug resistance. In the example of FIG. 5, the number _{NG of the} basic group is 6. In the phylogenetic tree of FIG. 5, the horizontal axis represents the basic group and the vertical axis represents the similarity. The phylogenetic tree is composed of a plurality of nodes n1 to n10 and a plurality of branches connecting them. The smaller the value on the vertical axis, the higher the similarity, and the larger the value on the vertical axis, the lower the similarity. The top node n0 is called the root node, and the bottom nodes n5 to n10 are called leaf nodes. Nodes n1 to n4 exist between the uppermost node n0 and the lowermost nodes n5 to n10.

In the example of FIG. 5, "Group01", "Group05", "Group02", "Group04", "Group03" and "Group06" belong to the nodes n5 to n10, respectively. Node n5 and node n6 are connected by node n4. This means that the drug resistance pattern of "Group 01" and the drug resistance pattern of "Group 05" are most similar. Node n4 and node n7 are connected by node n3. This means that the pattern of drug resistance of "Group 02" is next similar to the pattern of drug resistance of "Group 01" and "Group 05". For example, "Group 01" and "Group 05" differ in the presence or absence of resistance to one drug, and are the same in the presence or absence of resistance to a plurality of other drugs. For example, "Group 02" differs in the presence or absence of drug resistance to two drugs and is the same in the presence or absence of resistance to a plurality of other drugs. The pattern of drug resistance of "Group 06" is the most different from the pattern of drug resistance of "Group 01", "Group 05", "Group 02", "Group 04" and "Group 03".

"Group01" and "Group05" belong to node n4, "Group01", "Group05" and "Group02" belong to node n3, and "Group01", "Group05", "Group02" and "Group04" belong to node n2. , And node n1 belongs to "Group01", "Group05", "Group02", "Group04" and "Group03". The phylogenetic tree of FIG. 5 is displayed on the display unit 16.

By operating the operation unit 15, the user can specify a desired node ni in the phylogenetic tree displayed on the display unit 16. Here, i is any of 1 to 10. The specified node ni referred to as the attention node N _0. When the node N _{0 of interest} is specified, the child nodes N ₁ and N _{2 immediately below the node N 0} of interest are specified. In the example of FIG. 5, node n0 is designated as the target node N _0. Thereby, the node n1, n10 is identified as child nodes _N 1, _{N 2.} In this case, the base group "Group01" belonging to the child node N _1, "Group05", "Group02", "Group04" and "Group03" is reorganized reorganized group "GR01". In addition, the basic group "Group06" belonging to the child node N ₁ is re-organized into reorganization group "GR02".

The groups before and after the reorganization are displayed on the display unit 16. 6 (a) and 6 (b) are diagrams showing the groups before and after the reorganization, respectively. As shown in FIG. 6A, before the reorganization of the groups, a plurality of samples are classified into six basic groups “Group01” to “Group06”. Sample of After the reorganization of the group by the specified node of interest N _0, a sample of the basic group in the reorganization group "GR01", "Group01" - "Group05" belong, basic groups in the reorganization group "GR02", "Group06" Belongs to.

The reorganization group "GR01" and the reorganization group "GR02" differ in their resistance to one or a few specific drugs. The peak matrix of FIG. 3 is created for the reorganization groups "GR01" and "GR02". Based on the created peak matrix, the difference analysis is performed on the mass spectra corresponding to the samples belonging to the reorganization groups "GR01" and "GR02". Thereby, a marker peak for determining the presence or absence of resistance to a specific one or a small number of drugs is searched for.

Similarly, the user, by specifying any other node ni as the target node N _0, reorganized group "GR01" and "GR02" can be further reorganized into multiple other reorganization Group .. That is, by changing the aimed node N _0, it can be re-organized into a plurality of different reorganization group and the plurality of base group "Group01" - "Group06" Reorganization Group "GR01" and, and "GR02". Thereby, a marker peak for determining the presence or absence of resistance to one or a few other specific drugs is searched for.

As shown in FIG. 6, the display unit 16 displays check boxes corresponding to the groups before and after the reorganization, and also displays check boxes corresponding to the plurality of samples. The user can manually remove some groups or some samples from the mass spectrum difference analysis by manipulating these check boxes using the control unit 15. It can be added to the analysis of the difference due to. Thereby, it is also possible to manually reorganize the reorganization group.

By sequentially changing the node N ₀ of interest and repeating the same analysis, it is possible to efficiently search for a marker peak for determining the presence or absence of resistance to a desired drug even when the number of basic groups or the number of drugs is large. Can be done.

(4) Mass Spectrometry FIG. 7 is a diagram showing the configuration of the data analysis device 2. 8 and 9 are flowcharts showing an algorithm of mass spectrometry processing performed by a mass spectrometry program. As shown in FIG. 7, the data analysis device 2 has, as functional units, a data acquisition unit A, a peak list creation unit B, a group reception unit C, a classification unit D, a characteristic reception unit E, a phylogenetic tree creation unit F, and a peak matrix. It includes a creation unit G, a search unit H, a node reception unit I, a reorganization unit J, and a display control unit K. The peak list creation unit B, the peak matrix creation unit G, and the search unit H constitute the analysis unit L.

The functional unit of the data analysis device 2 is realized by the CPU 11 of FIG. 1 executing the mass spectrometry program stored in the storage device 14. A part or all of the functional parts of the data analysis device 2 may be realized by hardware such as an electronic circuit. Hereinafter, the mass spectrometry process will be described with reference to the data analysis apparatus 2 of FIG. 7 and the flowcharts of FIGS. 8 and 9.

First, the data acquisition unit A determines whether or not the mass spectrum data is designated by the operation unit 15 (step S1). By operating the operation unit 15, the user can specify the desired mass spectrum data among the plurality of mass spectrum data stored in the storage device 14. If the mass spectrum data is not specified, the data acquisition unit A waits until the mass spectrum data is specified. When the mass spectrum data is designated, the data acquisition unit A acquires the designated mass spectrum data from the storage device 14 (step S2). The peak list creation unit B creates a peak list based on the acquired mass spectrum data (step S3).

Next, the data acquisition unit A determines whether or not the end of the designation of the mass spectrum data is instructed (step S4). The user can instruct the end of the designation of the mass spectrum data by operating the operation unit 15. When the end of the designation of the mass spectrum data is not instructed, the data acquisition unit A determines whether or not the mass spectrum data is further designated by the operation unit 15 (step S5). If the mass spectrum data is further specified, the data acquisition unit A returns to step S2. If no further mass spectrum data is specified, the data acquisition unit A returns to step S4. Steps S2 to S5 are repeated until the end of the designation of the mass spectrum data is instructed.

When the end of the designation of the mass spectrum data is instructed, the display control unit K causes the group reception screen 20 of FIG. 2 to be displayed on the display unit 16 (step S6). The group reception unit C determines whether or not the operation unit 15 has received an instruction for classifying the sample into a basic group through the group reception screen 20 displayed in step S6 (step S7). If the instruction is not accepted, the group reception unit C waits until the instruction is accepted. When the instruction is received, the classification unit D creates a plurality of basic groups based on the received instruction and classifies the sample into one of the created basic groups (step S8). The display control unit K causes the display unit 16 to display the basic group (see FIG. 6A) classified in step S8 (step S9).

After that, the peak matrix creation unit G creates a peak matrix based on the peak list created in step S3 and the basic group classified in step S8 (step S10). The display control unit K causes the display unit 16 to display the created peak matrix (step S11). The search unit H analyzes the differences of the plurality of basic groups based on the created peak matrix (step S12), and searches for the marker peaks based on the analysis results of the differences (step S13). The display control unit K causes the display unit 16 to display the analysis result of the difference including the searched marker peak (step S14).

Subsequently, the display control unit K causes the display unit 16 to display the characteristic reception screen 30 of FIG. 4 (step S15). The characteristic reception unit E determines whether or not the characteristic information has been set by the operation unit 15 on the displayed characteristic reception screen 30 (step S16). If the characteristic information is not set, the group reception unit C waits until the characteristic information is set. When the characteristic information is set, the phylogenetic tree creation unit F creates a phylogenetic tree based on the similarity of the set characteristic information (step S17). The display control unit K causes the display unit 16 to display the created phylogenetic tree (see FIG. 5) (step S18). In step S18, a screen showing the pattern of drug resistance for the plurality of set basic groups may be displayed together with the phylogenetic tree.

The node reception unit I determines whether or not the operation unit 15 has accepted the designation of the node of interest in the phylogenetic tree displayed on the display unit 16 (step S19). When the designation of the node of interest is accepted, the reorganization unit J reorganizes the group based on the node of interest (step S20). The display control unit K causes the display unit 16 to display the reorganization group (see FIG. 6B) (step S21). In this case, a plurality of basic groups are reorganized into a plurality of reorganization groups.

After that, the peak matrix creation unit G creates a peak matrix based on the peak list created in step S3 and the plurality of reorganized groups reorganized in step S20 (step S22). The display control unit K causes the display unit 16 to display the created peak matrix (step S23). The search unit H analyzes the differences of the plurality of reorganized groups based on the created peak matrix (step S24), and searches for the marker peak based on the difference analysis result (step S25). The display control unit K causes the display unit 16 to display the analysis result of the difference including the searched marker peak (step S26). After that, the display control unit K returns to step S19.

When the designation of the node of interest is accepted in step S19, the processes of steps S20 to S26 are performed for the designated node of interest. If the designation of the node of interest is not accepted in step S19, the node reception unit I determines whether or not the end of the designation of the node of interest is instructed (step S27). If the end of the designation of the node of interest is not instructed, the node reception unit I returns to step S19. When the end of the designation of the node of interest is instructed, the node reception unit I ends the mass spectrometry process.

In the above mass spectrometry process, some processes may be omitted. For example, a part or all of the display processing of steps S9, S11, S14, S21, S26 and the like may be omitted. Further, steps S10 to S14 before the basic group is reorganized may be omitted. The designation of the node of interest in step S19 includes the designation of canceling the node of interest. When the cancellation of the node of interest is specified, the reorganization group is reorganized into the basic group in step S20. That is, the classification of the samples into groups is returned to the initial classification into basic groups.

(5) Effect In the mass spectrometer 1 according to the present embodiment, the user can use the node corresponding to the desired drug in the phylogenetic tree displayed on the display unit 16 even when the number of groups and the number of drugs are large. Can be easily specified as the node of interest. Further, the user does not need to perform an operation for reconstructing a plurality of groups belonging to the node of interest into one or more groups belonging to each of the plurality of child nodes. Further, the user can recursively repeat the designation of the node of interest. As a result, it is possible to efficiently search for a plurality of marker peaks for determining resistance to a plurality of desired drugs.

(6) Other Embodiments (a) In the above embodiment, the mass spectrometer 1 is a mass spectrometer using MALDI, but the present invention is not limited thereto. The mass spectrometer 1 may be a mass spectrometer using another method, or may be another analyzer such as chromatography.

(B) In the above embodiment, the characteristic information of the group is a combination of the presence or absence of resistance to a plurality of drugs, but the present invention is not limited to this. The characteristic information of the group may be the genetic information of the sample. In this case, a marker peak for determining the presence or absence of a predetermined gene (for example, a drug resistance gene) can be efficiently searched.

Claims (11)

A mass spectrometer that can be connected to the display unit.
A data acquisition unit that acquires analysis data for each of multiple samples,
A classification unit that classifies multiple samples into multiple basic groups,
A phylogenetic tree creation unit that creates a phylogenetic tree containing a plurality of nodes based on the similarity of drug resistance patterns including resistance to a plurality of specific drugs for the plurality of basic groups.
A display control unit that displays the created phylogenetic tree on the display unit,
A node reception unit that accepts the designation of any of the plurality of nodes as the designation of the node of interest, and
A plurality of reorganization groups are generated by reorganizing a plurality of basic groups belonging to a plurality of child nodes for the designated node of interest in the phylogenetic tree into a plurality of groups corresponding to the plurality of child nodes. Reorganization department and
A drug corresponding to the designated node of interest by analyzing the difference in the analysis data among the plurality of reorganization groups based on one or a plurality of analysis data corresponding to each of the plurality of reorganization groups. A mass spectrometer comprising an analysis unit for searching for a marker peak for determining resistance to resistance to. Each time the node reception unit accepts the designation of the node of interest, the reorganization unit corresponds to the plurality of basic groups belonging to the plurality of child nodes of the designated node of interest, respectively, to the plurality of child nodes. Generate multiple reorganization groups by reorganizing into multiple groups,
Each time the reorganization unit generates a plurality of reorganization groups, the analysis unit may perform the plurality of reorganizations based on one or a plurality of analysis data corresponding to each of the generated reorganization groups. The mass spectrometer according to claim 1, wherein a marker peak for determining resistance to a drug corresponding to the designated node of interest is searched for by analyzing a difference in analysis data between groups. The mass spectrometer according to claim 1 or 2, wherein the display control unit displays information indicating the searched marker peak on the display unit. The mass spectrometer according to any one of claims 1 to 3, wherein the display control unit displays the plurality of reorganization groups on the display unit. The plurality of analytical data are a plurality of mass spectrum data, and the plurality of mass spectrum data includes mass-to-charge ratios and detection intensities for the plurality of peaks.
The analysis unit
Based on the plurality of mass spectrum data acquired by the data acquisition unit, a peak list creation unit that creates a peak list showing the mass-to-charge ratio of the plurality of peaks and the detection intensity of each peak for each sample, and a peak list creation unit.
Based on the plurality of peak lists for the plurality of samples and the plurality of rearrangement groups, the plurality of mass-to-charge ratios arranged in the first direction and the plurality of rearrangements arranged in the second direction. A peak matrix creation unit that creates a peak matrix including a group of samples, the plurality of mass-to-charge ratios, and a plurality of detection intensities corresponding to the plurality of samples.
Any of claims 1 to 4, including a search unit that searches for marker peaks by analyzing differences between the plurality of reorganization groups based on a plurality of detection intensities corresponding to each mass-to-charge ratio of the peak matrix. The mass spectrometer according to one item. The mass spectrometer according to claim 5, wherein the search unit searches for a marker peak corresponding to the designated node of interest by univariate analysis of a plurality of detection intensities corresponding to each mass-to-charge ratio of the peak matrix. The mass spectrometer according to any one of claims 1 to 6, wherein the resistance to the plurality of specific agents includes the presence or absence of resistance to the plurality of agents. The drug resistance pattern contains genetic information and
The mass spectrometer according to any one of claims 1 to 6, wherein the resistance to the plurality of specific agents includes a plurality of gene types. A storage device that stores analytical data for each of multiple samples,
The operation unit operated by the user and
With a display unit
The data acquisition unit acquires the plurality of analysis data from the storage device, the display control unit displays the created phylogenetic tree on the display unit, and the analysis unit is the operation unit by the user. The mass spectrometer according to any one of claims 1 to 8, which searches for a marker peak based on an operation. This is a mass spectrometry method using a display unit.
Steps to obtain analytical data for each of multiple samples,
Steps to classify multiple samples into multiple basic groups,
A step of creating a phylogenetic tree containing a plurality of nodes based on the similarity of drug resistance patterns including resistance to a plurality of specific drugs for the plurality of basic groups.
The step of displaying the created phylogenetic tree on the display unit,
A step of accepting the designation of one of the plurality of nodes as the designation of the node of interest, and
A plurality of reorganization groups are generated by reorganizing a plurality of basic groups belonging to a plurality of child nodes for the designated node of interest in the phylogenetic tree into a plurality of groups corresponding to the plurality of child nodes. Steps and
A drug corresponding to the designated node of interest by analyzing the difference in the analysis data among the plurality of reorganization groups based on one or a plurality of analysis data corresponding to each of the plurality of reorganization groups. A mass spectrometric method comprising the step of searching for marker peaks to determine resistance to. A mass spectrometry program that can be executed by a processing device connected to the display unit.
The process of acquiring analysis data for each of multiple samples,
The process of classifying multiple samples into multiple basic groups,
A process of creating a phylogenetic tree containing a plurality of nodes based on the similarity of drug resistance patterns including resistance to a plurality of specific drugs for the plurality of basic groups.
The process of displaying the created phylogenetic tree on the display unit,
The process of accepting the designation of one of the plurality of nodes as the designation of the node of interest, and
A plurality of reorganization groups are generated by reorganizing a plurality of basic groups belonging to a plurality of child nodes for the designated node of interest in the phylogenetic tree into a plurality of groups corresponding to the plurality of child nodes. Processing and
A drug corresponding to the designated node of interest by analyzing the difference in the analysis data among the plurality of reorganization groups based on one or a plurality of analysis data corresponding to each of the plurality of reorganization groups. The process of searching for marker peaks to determine resistance to
A mass spectrometric program to be executed by the processing apparatus.

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