阅读说明：本技术 一种结核分枝杆菌的药物敏感性检测方法 (Drug sensitivity detection method for mycobacterium tuberculosis ) 是由 杨瑜 李华 刘志辉 刘�文 于 2021-01-27 设计创作，主要内容包括：本发明涉及药物敏感性检测领域,特别是涉及一种结核分枝杆菌的药物敏感性检测方法。本发明的结核分枝杆菌的药物敏感性检测方法,包括：S1：制备结核分枝杆菌菌液；S2：用含药物的培养基对S1中的结核分枝杆菌菌种进行培养；S3：对S2的培养物进行MPT64抗原检测,获得检测结果；S4：对S3的MPT64抗原检测结果进行分析,得出结核分枝杆菌药物敏感性结论。本发明的检测方法通过监测MPT64的分泌情况,反映出结核分枝杆菌在对应的待评估药物作用下的生长状况,最终实现对结核分枝杆菌的耐药性的评估。本发明的检测方法,可以同时检测结核分枝杆菌对多种药物的敏感性检测,不限于本发明所例举的利福平、异烟肼两种药物。(The invention relates to the field of drug sensitivity detection, in particular to a drug sensitivity detection method for mycobacterium tuberculosis. The drug sensitivity detection method of mycobacterium tuberculosis comprises the following steps: s1: preparing mycobacterium tuberculosis bacterial liquid; s2: culturing Mycobacterium tuberculosis strain in S1 with culture medium containing medicine; s3: performing MPT64 antigen detection on the culture of S2 to obtain a detection result; s4: and analyzing the MPT64 antigen detection result of S3 to obtain the result of drug sensitivity of the mycobacterium tuberculosis. The detection method reflects the growth condition of the mycobacterium tuberculosis under the action of the corresponding drug to be evaluated by monitoring the secretion condition of MPT64, and finally realizes the evaluation of the drug resistance of the mycobacterium tuberculosis. The detection method of the present invention can detect the sensitivity of mycobacterium tuberculosis to various drugs simultaneously, and is not limited to rifampicin and isoniazid, which are exemplified in the present invention.)

1. A method for detecting drug sensitivity of Mycobacterium tuberculosis is characterized by comprising the following steps:

s1: preparing mycobacterium tuberculosis bacterial liquid;

s2: culturing Mycobacterium tuberculosis strain in S1 with culture medium containing medicine;

s3: performing MPT64 antigen detection on the culture of S2 to obtain a detection result;

s4: and analyzing the MPT64 antigen detection result of S3 to obtain the result of drug sensitivity of the mycobacterium tuberculosis.

2. The method for drug-sensitive detection of Mycobacterium tuberculosis as set forth in claim 1, wherein the drug contained in the drug-containing medium in S2 comprises rifampicin or isoniazid.

3. The method for drug-sensitive detection of Mycobacterium tuberculosis as set forth in claim 2, wherein when the drug in S2 is rifampicin, the concentration of rifampicin in the drug-containing medium is 1.0 μ g/mL; when the drug in the S2 is isoniazid, the concentration of the isoniazid in the culture medium containing the drug is 0.2 mu g/mL.

4. The method for drug-sensitive detection of Mycobacterium tuberculosis as set forth in any one of claims 1-3, wherein the ratio of S1: the preparation method of the mycobacterium tuberculosis bacterial liquid comprises the following specific operations:

s11: confirming that the bacteria to be detected is mycobacterium tuberculosis;

s12: purifying the mycobacterium tuberculosis flora to be detected, and preparing mycobacterium tuberculosis bacterial liquid.

5. The method for drug-sensitive detection of Mycobacterium tuberculosis as set forth in claim 4, wherein the S12 purging operation comprises: placing the mycobacterium tuberculosis flora to be detected in physiological saline, carrying out ultrasonic homogenization to obtain suspension, transferring the suspension to a centrifugal tube, centrifuging for 10-15min at 10000-14000rpm, and discarding supernatant; repeating the operation for 2-3 times to obtain pure mycobacterium tuberculosis thallus; then the pure mycobacterium tuberculosis thallus is re-suspended to prepare the mycobacterium tuberculosis bacterial liquid with the concentration of 0.1 McLee.

6. The method for drug sensitivity detection of Mycobacterium tuberculosis as set forth in any one of claims 1-3, wherein the Mycobacterium tuberculosis species culturing procedure of S2 comprises:

inoculating the mycobacterium tuberculosis bacterial liquid prepared in the step S1 to a culture medium containing medicaments, wherein the final concentration of the mycobacterium tuberculosis in the culture medium is 0.01 McLee/7 mL, and then culturing for 7-10 days at 37 ℃.

7. The method for drug-sensitive detection of Mycobacterium tuberculosis as set forth in any one of claims 1-3, wherein the ratio of S3: MPT64 antigen detection comprising: centrifuging the culture obtained in step S2; the centrifugation conditions were: centrifuging at 10000-14000rpm for 5-10 min; then taking a supernatant sample, carrying out MPT64 antigen detection on the supernatant sample by adopting a colloidal gold immunochromatography method, and collecting a detection result.

8. The method for drug-sensitive detection of Mycobacterium tuberculosis as set forth in any one of claims 1-3, wherein the S4 includes:

s41: imaging the detection result of the S3, and performing gray level analysis on the strips of the formed image to obtain the gray level value of the sample detection strip and the gray level value of the quality control strip;

s42: calculating a gray ratio and judging a result;

the calculation method of the gray scale ratio comprises the following steps: and setting the gray value of the quality control band as 1, and calculating the gray ratio of the gray value of the sample detection band and the gray value of the quality control band.

9. The method for drug-sensitive detection of Mycobacterium tuberculosis as set forth in claim 8, wherein in S42, the interpretation criteria include:

when the medicament in the culture medium containing the medicament in the S2 is rifampicin, the gray scale ratio is more than 0.23, and the mycobacterium tuberculosis to be detected can be judged to be rifampicin-resistant mycobacterium tuberculosis; if the gray scale ratio is lower than 0.23, the mycobacterium tuberculosis is judged to be rifampicin sensitive;

when the medicine in the culture medium containing the medicine in the S2 is isoniazid, the gray scale ratio is more than 0.2, the mycobacterium tuberculosis to be detected can be judged to be isoniazid-resistant mycobacterium tuberculosis, and the gray scale ratio is less than 0.2, the mycobacterium tuberculosis can be judged to be isoniazid-sensitive mycobacterium tuberculosis.

10. The method for drug-sensitive detection of Mycobacterium tuberculosis as claimed in any one of claims 1-9, wherein the detection method is further applicable to drug-sensitive detection of Mycobacterium tuberculosis for streptomycin, ethambutol or pyrazinamide; the specific operation comprises the following steps: the drug to be evaluated added to the culture medium in step S2 is streptomycin, ethambutol, or pyrazinamide.

Technical Field

The invention relates to the field of drug sensitivity detection, in particular to a drug sensitivity detection method for mycobacterium tuberculosis.

Background

The multi-drug resistant tuberculosis is tuberculosis with drug resistance to two anti-tuberculosis drugs, namely rifampicin and isoniazid, and the confirmation of the diagnosis needs bacteriological confirmation and the rapid detection of the drug resistance. The current techniques applied to the detection of drug sensitivity to tuberculosis are classified into phenotypic method and genetic method. The method has the advantages that the absolute concentration method and the proportional method which are widely used are recommended by the world health organization, the method is simple to operate and economical, the proportional method is considered as a gold standard for detecting the drug sensitivity of the mycobacterium tuberculosis, the consumed time is long, and the drug sensitivity result can be obtained after 4-6 weeks are needed after the isolated strain is obtained. In the current phenotype-based drug sensitivity detection method, BACTECCMGIT is used⁹⁶⁰And3D is the most common, but the former is expensive and the latter has a minimum of 10 days of detection time. In addition, the principle of the two phenotypic detection methods is based on oxygen and carbon dioxide generated by microbial metabolism, and the two phenotypic detection methods have no specificity to mycobacterium tuberculosis and cannot exclude pollution. In recent years, various molecular techniques such as linear probe assay, DNA sequencing, Gene Xpert Mycobacterium tuberculosis/RIF, etc. have been developed as rapid screening methods for mutant genes to detect drug-resistant Mycobacterium tuberculosis faster than conventional phenotypic drug sensitivity detection. The former can only detect the drug sensitivity of rifampicin, while the latter can detect the drug sensitivity of isoniazid, but the sensitivity and specificity of the detection of the drug sensitivity of isoniazid are 84.44% -92.00% and 94.93% -100.00% respectively. Among all anti-mycobacterium tuberculosis drugs, rifampin-resistant genes have been studied most clearly. The molecular method for detecting rifampicin drug sensitivity is mainly based on the mutation of mycobacterium tuberculosis rifampicin resistance gene RpoB, but only 95% of mycobacterium tuberculosis rifampicin resistance is related to the gene mutation.

It can be seen that although these molecular methods are faster than the conventional phenotypic drug susceptibility detection, the molecular-based detection methods can only detect the mutation of drug-resistant genes clearly associated with the phenotype, and cannot identify the undefined drug-resistant genes, resulting in lower accuracy, and secondly, these molecular techniques, apart from requiring special instruments and trainers, cannot be popularized in a comprehensive manner, thus limiting the application of the methods.

Therefore, the research and development of a rapid, accurate and simple drug sensitivity detection method is an important example for preventing and treating drug-resistant tuberculosis. The development of an accurate, timely and direct drug sensitivity test method for the mycobacterium tuberculosis is very important for finding, correctly treating and controlling the spread of drug-resistant tuberculosis.

Disclosure of Invention

Based on the above, the present invention aims to provide a method for detecting drug sensitivity of mycobacterium tuberculosis, which can accurately, timely and directly detect drug sensitivity of rifampicin, isoniazid or other anti-tuberculosis drugs of the mycobacterium tuberculosis.

The technical scheme of the invention is as follows:

a method for drug-sensitive detection of Mycobacterium tuberculosis, comprising:

s1: preparing mycobacterium tuberculosis bacterial liquid;

s2: culturing Mycobacterium tuberculosis strain in S1 with culture medium containing medicine;

s3: performing MPT64 antigen detection on the culture of S2 to obtain a detection result;

s4: and analyzing the MPT64 antigen detection result of S3 to obtain the result of drug sensitivity of the mycobacterium tuberculosis.

Further, the method for detecting drug sensitivity of Mycobacterium tuberculosis of the present invention is used for detecting drug sensitivity of rifampicin and/or isoniazid of Mycobacterium tuberculosis.

Further, the step S1: preparing a mycobacterium tuberculosis bacterial solution, which comprises the following steps:

s11: and (3) confirming the flora to be detected: confirming that the detected flora is mycobacterium tuberculosis;

s12: purifying the mycobacterium tuberculosis flora to be detected, and preparing mycobacterium tuberculosis bacterial liquid.

Preferably, the purification operation of S12 includes: placing the mycobacterium tuberculosis flora to be detected in physiological saline, carrying out ultrasonic homogenization to obtain suspension, transferring the suspension to a centrifugal tube, centrifuging for 10-15min at 10000-; repeating the step for 2-3 times to obtain pure mycobacterium tuberculosis thallus; and then resuspending the pure mycobacterium tuberculosis thallus to prepare the mycobacterium tuberculosis bacterial liquid. The operation can fully remove secretory proteins on the surface of the mycobacterium tuberculosis thallus, such as MPT64 protein, and the like, and avoid influencing the accuracy of the detection result. The centrifugation is preferably carried out at 12000rpm for 10 min.

Preferably, the concentration of the mycobacterium tuberculosis bacterial liquid is 0.1 McLeod.

Further, the mycobacterium tuberculosis strain culturing operation of S2 includes:

and (4) inoculating the mycobacterium tuberculosis bacterial liquid prepared in the step (S1) to a culture medium containing a medicament to be evaluated, and culturing for 7-10 days at 37 ℃. The detection performance is best after the verification and culture for 7-10 days, and the interpretation critical value is unchanged.

Preferably, the final concentration of the Mycobacterium tuberculosis in the culture medium is 0.01M/7 mL.

Further, when the drug to be evaluated is rifampicin, the concentration of rifampicin in the medium is 1.0. mu.g/mL.

Further, when the drug to be evaluated is isoniazid, the concentration of isoniazid in the culture medium is 0.2 μ g/mL.

The initial concentration of the mycobacterium tuberculosis inoculation and the drug addition concentration can influence the concentration of MPT64 antigen protein in the culture after the culture is finished, so that the gray scale ratio is further influenced, and the drug sensitivity conclusion is influenced.

Further, the step S3: MPT64 antigen detection comprising: performing MPT64 antigen detection on the culture of S2 by adopting a colloidal gold immunochromatography method, and collecting a detection result;

preferably, the S3 further includes: centrifuging the culture obtained in step S2 before MPT64 antigen detection; the centrifugation conditions were: centrifuging at 10000-14000rpm for 5-10 min to separate solid from liquid, and clarifying; then taking a supernatant sample for MPT64 antigen detection. The preferred centrifugation conditions are: centrifuge at 12000rpm for 5 min.

Further, the S4 includes:

s41: imaging the detection result of the S3, and performing gray level analysis on the strips of the formed image to obtain the gray level value of the sample detection strip and the gray level value of the quality control strip;

s42: and calculating the gray scale ratio and judging the result.

Preferably, the imaging processing operation includes: and imaging the detection result by adopting a white light mode of the imager. Besides, the scanner can be used to scan and image the detection result.

Preferably, in S42, the gray scale ratio is calculated by: and setting the gray value of the quality control band to be 1, and calculating the gray ratio of the gray value of the sample detection band to the gray value of the quality control band (the gray value of the sample detection band/the gray value of the quality control band).

Preferably, in S42, the interpretation criteria include:

when the drug to be evaluated is rifampicin, if the gray scale ratio is more than 0.23, the mycobacterium tuberculosis to be detected can be judged to be rifampicin-resistant mycobacterium tuberculosis; if the gray scale ratio is less than 0.23, the rifampicin-sensitive mycobacterium tuberculosis can be judged.

Preferably, in S42, the interpretation criteria include:

when the drug to be evaluated is isoniazid, the gray scale ratio is more than 0.2, the mycobacterium tuberculosis to be detected can be judged to be isoniazid drug-resistant mycobacterium tuberculosis, and the gray scale ratio is less than 0.2, the mycobacterium tuberculosis to be detected can be judged to be isoniazid sensitive mycobacterium tuberculosis.

The application of the drug sensitivity detection method of mycobacterium tuberculosis of the present invention includes, but is not limited to, detection of drug sensitivity of mycobacterium tuberculosis to rifampicin and isoniazid, and other drugs, such as streptomycin, ethambutol, pyrazinamide, and the like, are also suitable for the drug sensitivity detection method of mycobacterium tuberculosis of the present invention, and specifically, the rifampicin and isoniazid added into the culture medium in step S2 are replaced by other antitubercular drugs to be evaluated.

The invention has the beneficial effects that:

the detection method reflects the growth condition of the mycobacterium tuberculosis under the action of the corresponding drug to be evaluated by monitoring the secretion condition of MPT64, and finally realizes the evaluation of the drug resistance of the mycobacterium tuberculosis. The detection method of the present invention can detect the sensitivity of mycobacterium tuberculosis to various drugs simultaneously, and is not limited to rifampicin and isoniazid, which are exemplified in the present invention.

As recognized in the art, the time required for the proportional method, the absolute concentration method and the like is about 6 weeks, BACTEC MGIT⁹⁶⁰The sensitivity and specificity of the genotype method for detecting isoniazid are 84.44% -92.00% and 94.93% -100.00% respectively in 10 days. Compared with the prior art, the method takes the content of MPT64 in the culture supernatant of the mycobacterium tuberculosis as a detection index to detect the rifampicin and isoniazid sensitivity of the mycobacterium tuberculosis, the principle is based on phenotype, the mycobacterium tuberculosis specificity is realized, the detection time is greatly shortened, and the method is quicker (7 days) and more efficient (simple to operate) than a proportional method and an absolute concentration method and is quicker (7 days) and more efficient than BACTEC MGIT⁹⁶⁰And3D has good specificity, low price (the cost price is about 35 yuan/reaction), and higher specificity (100 percent) than the genotype method. In addition, the method is based on phenotype detection, and can also be used for detecting the drug sensitivity of other anti-tuberculosis drugs.

Compared with the molecular detection method which only can detect the mutation of the drug-resistant gene which is definitely related to the phenotype but cannot identify the current situation of the undetermined drug-resistant gene, the detection method of the invention reflects the drug-resistant situation which is closer to the actual drug-resistant situation of the pathogenic bacteria and provides more reliable basis for clinic.

The detection method of the invention has no difference (P is less than 0.05) in the detection result of the gold standard ratio method of proofreading and drug sensitivity detection of mycobacterium tuberculosis, has good detection performance and good market value, and can be widely popularized and applied.

Drawings

Figure 1 is a graph of the subject' S working characteristics for rifampicin and isoniazid resistance detection indicated with MPT64, where S: sensitive plants; MDR: drug-resistant strains; *: p is less than 0.05; RFP: rifampin; INH: isoniazid.

Detailed Description

The terms of orientation of up, down, left, right, front, back, top, bottom, and the like, referred to or may be referred to in this specification, are defined relative to their configuration, and are relative concepts. Therefore, it may be changed according to different positions and different use states. Therefore, these and other directional terms should not be construed as limiting terms.

The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

The specific techniques or conditions not indicated in the examples of this application are performed according to the techniques or conditions described in the literature in the field or according to the product description. The reagents or instruments used in the examples of the present application are not indicated by manufacturers, and are all conventional products available from commercial sources and the like.

Example drug sensitive detection of Rifampicin and/or Isoniazid of Mycobacterium tuberculosis

1 apparatus and materials

The mycobacterium tuberculosis strains used in the experiment are all derived from a mycobacterium tuberculosis strain library of a key laboratory tuberculosis research laboratory in respiratory disease countries, are all identified as mycobacterium tuberculosis by biochemical and molecular methods, and the drug sensitivity of the strains is identified by a proportional method.

A mycobacterium tuberculosis antigen detection kit (colloidal gold method) provided by Hangzhou innovative biological detection and control technology, Inc.;

gel imaging system (BioRad);

the bacterial ultrasonic disperser BACSpreaderTM 1100 is produced by Guangdong body Bi kang Biotech limited;

middlebrook 7H10 solid medium and Middlebrook 7H9 liquid medium were purchased from BD corporation, USA.

2 drug susceptibility test

The method comprises the following specific operation steps:

s1: after confirming the mycobacterium tuberculosis, putting the mycobacterium tuberculosis into physiological saline, ultrasonically homogenizing the mycobacterium tuberculosis into suspension, transferring the suspension to a centrifugal tube, centrifuging the suspension at 12000rpm for 10min, and discarding the supernatant; repeating the step for 2-3 times, and fully removing secreted proteins on the surfaces of the thalli, particularly MPT64 antigen protein generated before the step to obtain pure thalli; then, the pure bacteria is re-suspended by normal saline and the concentration of the bacteria is adjusted to be 0.1 McLeod, so as to obtain the mycobacterium tuberculosis bacterial liquid.

In this step, the antigen detection kit can be used to check whether the MPT64 antigen protein is completely removed after washing with physiological saline.

S2: the bacterial liquid is sucked and inoculated in a drug culture medium, the final concentration of the mycobacterium tuberculosis is 0.01 McLee/7 mL, the final concentration of the drug culture medium rifampicin and isoniazid is 1.0 mu g/mL and 0.2 mu g/mL respectively, and the mycobacterium tuberculosis is cultured for 7 days at 37 ℃.

S3: detecting MPT64 antigen by colloidal gold method: and (3) centrifuging the culture of S2 at 12000rpm for 5min, adding 100 mu L of supernatant into a sample hole of a detection plate of the mycobacterium tuberculosis antigen detection kit according to the instruction of a product specification, standing at room temperature for 15min, and observing the result. The result is effective when the quality control band appears, and the reagent is invalid when no quality control band appears, and the reagent needs to be replaced for retesting; wherein the presence of both the control band and the test band is indicative of a positive MPT64 test; only the quality control band indicates negative detection.

S4: respectively imaging each group of detection plates with effective detection results in S3 by using a BioRad imager in a white light mode, and then performing stripe gray scale analysis (software name: Image lab)^TM3.0) to obtain the strip gray value; setting the gray value of the quality control band as 1, calculating the gray ratio in a mode of 'the gray value of the sample detection band/the gray value of the quality control band', and then obtaining the conclusion of the drug sensitivity of the mycobacterium tuberculosis according to the gray ratio and the interpretation standard.

Interpretation criteria:

when the gray ratio of MPT64 of the rifampicin drug-added culture medium supernatant is larger than 0.23, the mycobacterium tuberculosis to be detected is judged to be rifampicin-resistant mycobacterium tuberculosis, and when the gray ratio is lower than the value, the mycobacterium tuberculosis is judged to be rifampicin-sensitive bacteria.

When the MPT64 gray scale ratio of the isoniazid dosing culture medium supernatant is larger than 0.2, the mycobacterium tuberculosis to be detected is judged to be isoniazid drug-resistant mycobacterium tuberculosis, and when the MPT64 gray scale ratio is lower than the value, the mycobacterium tuberculosis is judged to be isoniazid sensitive bacteria.

EXAMPLE two evaluation of detection Performance of the drug sensitivity detection method for Mycobacterium tuberculosis of the present invention

The procedure for drug-sensitive detection of Mycobacterium tuberculosis in this example is the same as that in example 1.

When the drugs act for 7 days, the rifampicin and isoniazid drug sensitivity of mycobacterium tuberculosis can be accurately identified by a colloidal gold method based on MPT64 antigen, and the areas under ROC curves for detecting rifampicin resistance and isoniazid resistance are all 1 according to the analysis of a receiver operating characteristic curve (ROC). The chi-square test shows that the detection result of the method is not different from that of the gold standard proportion method for detecting the drug sensitivity of the mycobacterium tuberculosis (P is less than 0.05), the detection performance is good, the market value is good, and the method can be widely popularized and applied.

The detection method is rapid and high in accuracy, can be used for simultaneously detecting the sensitivity of the mycobacterium tuberculosis to various drugs, is not limited to two drugs of rifampicin and isoniazid exemplified by the invention, and other drugs such as streptomycin, ethambutol and pyrazinamide are also suitable for the drug sensitivity detection method of the mycobacterium tuberculosis, and particularly only needs to replace the rifampicin and isoniazid added into the culture medium in the step S2 with other antituberculosis drugs to be evaluated.

Example three drug treatment time validation

Drug sensitivity detection of rifampicin and/or isoniazid of Mycobacterium tuberculosis was performed separately, 3 sets of detection were performed for each drug, the culture time in step S2 was selected to be 3 days, 7 days, and 10 days, respectively, and the other was performed according to the procedure of example one.

The gray scale ratio of the MPT64 detection band at each time point and each strain at 3, 7 and 10 days after the treatment of each drug is respectively detected, and the working characteristic curve of the subject for the rifampicin and isoniazid resistance detection indicated by MPT64 is respectively drawn according to the gray scale ratio, as shown in figure 1.

The results show that: for rifampicin and isoniazid, the area under the working characteristic curve line of the subject at 3 days was 0.84 and 0.77, respectively; and when 7 days and 10 days, the area under the working characteristic curve line of the subject is 1, and the method has the best detection performance when the medicine is treated for 7-10 days.

Example four verification of critical value

Selecting 12 mycobacterium tuberculosis sensitive strains and 11 multi-drug resistant strains, carrying out experiments according to the operation steps in the first embodiment, analyzing the gray scale of MPT64 detection bands after 3 days, 7 days and 10 days of drug treatment, calculating the detection performance of the method on drug sensitivity detection of mycobacterium tuberculosis through a test subject working curve, and displaying that when the drug to be evaluated is rifampicin, the drug treatment is carried out for 7 days, and the optimal detection threshold value is 0.23. The method is verified in 34 strains of mycobacterium tuberculosis with definite drug sensitivity results (ratio method), the detection sensitivity is 92.9 percent, and the specificity is 100.0 percent. Based on the above, 0.23 is used as the interpretation critical value for detecting the sensitivity of the mycobacterium tuberculosis to rifampicin, namely, the gray scale ratio is more than 0.23, and the mycobacterium tuberculosis to be detected can be judged to be rifampicin drug-resistant mycobacterium tuberculosis; if the gray scale ratio is less than 0.23, the rifampicin-sensitive mycobacterium tuberculosis can be judged.

The verification process is the same as above, when the drug to be evaluated is isoniazid, the drug is treated for 7 days, and the optimal detection threshold value is 0.2. The method is verified in 34 mycobacterium tuberculosis strains with definite drug sensitivity results (ratio method), the detection sensitivity is 87.5 percent, and the specificity is 100.0 percent. Based on the above, 0.2 is used as an interpretation critical value for detecting the sensitivity of the mycobacterium tuberculosis to isoniazid, namely, the gray scale ratio is more than 0.2, the mycobacterium tuberculosis to be detected can be judged to be isoniazid drug-resistant mycobacterium tuberculosis, and the gray scale ratio is less than 0.2, the mycobacterium tuberculosis can be judged to be isoniazid sensitive mycobacterium tuberculosis.

Analysis of other conditions

MPT64 is a protein secreted in large amount in the process of growth and reproduction of Mycobacterium tuberculosis in early and middle stages, does not exist in nontuberculous mycobacteria and BCG strains, and is an important antigen capable of rapidly identifying Mycobacterium tuberculosis. MPT64 is highly related to growth of mycobacterium tuberculosis, theoretically, when the mycobacterium tuberculosis is cultured in vitro liquid for drug sensitivity test, if the mycobacterium tuberculosis is a sensitive strain, the growth of the mycobacterium tuberculosis is inhibited after the drug is added for treatment, and the secretion of MPT64 is reduced; on the contrary, in the case of the drug-resistant strain, the secretion of MPT64 was not affected after the drug treatment. This is also the theoretical basis of the present invention.

The scholars of He Xia et al (research on rapid detection of growth of Mycobacterium tuberculosis by using MPT64 as a target, 2010) discussed the possibility of using MPT64 as a rapid detection indication of growth of Mycobacterium tuberculosis and established an accurate, rapid, simple and convenient method for detecting growth of Mycobacterium tuberculosis (hereinafter referred to as "research on what"). The result proves that the MPT64 is used as the target to rapidly detect the growth of the mycobacterium tuberculosis, the result is accurate and rapid, and the operation is simple and convenient. From this point on, MPT64 has been widely accepted by the academia as an index for evaluating the growth status of Mycobacterium tuberculosis.

Then, schwann et al (study on suitable detection time points for using MPT64 secretion as an indication of growth of mycobacterium tuberculosis, journal of practical medicine, 2012) studied on suitable detection time for using an immunocolloidal gold method to detect mycobacterium tuberculosis complex specific secretory protein MPT64 for indicating growth of mycobacterium tuberculosis (hereinafter, referred to as "a study"). The result shows that 60 percent and more than 95 percent of MPT64 positive samples can be detected respectively at the end of 2 and 4 weeks and can be respectively regarded as suitable time points for rapid detection and culture end point detection, which provides scientific basis for creating a novel and practical tubercle bacillus isolation culture method. In the scheme of the invention, the detection time point is advanced from the 2 nd week of the previously disclosed and licensed research to the 7 th to 10 th days of the drug culture by optimizing and accurately controlling parameters such as strain concentration, drug concentration and the like and parameter relations, and some specific auxiliary treatment modes of the experimental process, such as flora purification operation, culture detection pretreatment and the like.

Yuer et al (research on three genes of isoniazid-resistant strain and sensitive strain MTB and their expression differences, 2014) compared the differences in DNA, mRNA and protein levels of Mycobacterium tuberculosis isoniazid-resistant strain and sensitive strains fbpB, MPT64 and psts1 and screened proteins related to the production of Mycobacterium tuberculosis isoniazid resistance by isolated culture and examination of sputum collected from Sinkiang region from tuberculosis patients (hereinafter "research on Yuan"). The expression levels of mRNA of 3 genes of the isoniazid drug-resistant strain and the sensitive strain after the isoniazid induction treatment are detected, the difference of mRNA levels of MPT64 genes in the mycobacterium tuberculosis drug-resistant strain and the sensitive strain is found to have no statistical significance (P is more than 0.05), and the conclusion that MPT64 is irrelevant to isoniazid drug resistance generated by mycobacterium tuberculosis is obtained. This seems to be contrary to the results of the present invention, which are not true. The analysis of the table was believed to lead to a conclusion corresponding to the experimental design used, which is different from the previous findings, mainly because the induction treatment time of the strain with isoniazid in the table study was only 72 hours, whereas the secretion of MPT64 from the M.tuberculosis strain at 72 hours was lower and could not be detected according to the previous studies, as in the many studies, and of course, it was much less likely to show the difference between the drug-resistant strain and the sensitive strain. Therefore, the invention also performs corresponding experimental verification aiming at the drug treatment time, and the results are shown in the third embodiment, and the results show that the drug treatment for 3 days is still not the optimal detection time after strictly controlling the operation and parameter accuracy of each step according to the optimized treatment method operation of the invention. This also corresponds to some extent to the findings of many studies.

In addition, in the studies of the drug concentration, the strain was treated with isoniazid in order to induce changes in its MPT64 gene, and then the mutation of MPT64 gene under isoniazid induction was determined by measuring the mRNA expression level. On the basis of the theory disclosed in detail in what, many, etc. of the present invention, the purpose of treating the strain with a drug is to kill the strain sensitive to the drug, based on the purpose as a reference for clinical application. Although the Table study does not disclose the concentration of isoniazid drug, the concentration of the drug induced by the induction treatment is necessarily different from that of the bactericidal drug, which is a conclusion that can be obviously drawn by those skilled in the art.

The kit is used for detecting MPT64, and as shown by researches of scholars of vengeant and the like (polymorphism of MPT64 protein of Mycobacterium tuberculosis in China and sensitivity influence on MPT64 antigen detection kit, 2015), the polymorphism of MPT64 protein of Mycobacterium tuberculosis in China can cause false negative of the MPT64 antigen detection kit due to 63bp deletion (wherein the total number of 180 strains, 8 strains have 63bp deletion, and the false negative rate is about 4.4 percent), and certain single-site mutations have no influence on the detection efficiency. The MPT64 protein is used as an important detection index, the application prospect of later research is wide to be expected, and some basic conditions of the MPT64 protein polymorphism need to be clarified before further research. Based on this, the Munichi et al (Mycobacteria tuberculosis MPT64 gene mutation research 2016) further made statistics and analysis on the polymorphism of MPT64 protein, and the results showed that the mutation frequency of Mycobacterium tuberculosis MPT64 gene is very low (45 clinical strains in total, 63bp gene deletion mutation exists in 1 strain, and the mutation probability is about 2.2%). The influence of the low incidence of the MPT64 protein polymorphism of the Mycobacterium tuberculosis in China on the detection method can be ignored, and the universal applicability of the drug sensitivity detection method of the Mycobacterium tuberculosis in the invention is not influenced.

The detection method reflects the growth condition of the mycobacterium tuberculosis in the corresponding drug culture medium to be evaluated by monitoring the secretion condition of MPT64, and finally realizes the evaluation of the drug resistance of the mycobacterium tuberculosis. The detection method of the present invention can detect the sensitivity of mycobacterium tuberculosis to various drugs simultaneously, and is not limited to rifampicin and isoniazid, which are exemplified in the present invention.

Compared with the prior art, the method takes the content of MPT64 in the culture supernatant of the mycobacterium tuberculosis as a detection index to detect the rifampicin and isoniazid sensitivity of the mycobacterium tuberculosis, the principle is based on phenotype, the mycobacterium tuberculosis specificity is realized, the detection time is greatly shortened, and the method is quicker (7 days) and more efficient (simple to operate) than a proportional method and an absolute concentration method and is quicker (7 days) and more efficient than BACTEC MGIT⁹⁶⁰And3D has good specificity, low price (the cost price is about 35 yuan/reaction), and higher specificity (100 percent) than the genotype method. The detection method provided by the invention integrates the advantages of various prior arts, and solves the problems of detection accuracy, detection efficiency, detection cost and the like. In addition, the method is based on phenotype detection, and can also be used for detecting the drug sensitivity of other anti-tuberculosis drugs.

Compared with the molecular detection method which only can detect the mutation of the drug-resistant gene which is definitely related to the phenotype but cannot identify the current situation of the undetermined drug-resistant gene, the detection method of the invention reflects the drug-resistant situation which is closer to the actual drug-resistant situation of the pathogenic bacteria and provides more reliable basis for clinic.

The detection method of the invention has no difference (P is less than 0.05) in the detection result of the gold standard ratio method of proofreading and drug sensitivity detection of mycobacterium tuberculosis, has good detection performance and good market value, and can be widely popularized and applied.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.