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Current status of drug-resistant tuberculosis infection |
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According to the World Health Organization (WHO) Global Tuberculosis Report 2023 , the expert group of the World Health Organization and the Tuberculosis Prevention and Control Center of the Chinese Center for Disease Control and Prevention jointly calculated and analyzed: The estimated number of new tuberculosis patients in my country in 2022 is 748,000 (780,000 in 2021), and the estimated tuberculosis incidence rate is 52/100,000 (55/100,000 in 2021). The estimated number of multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) cases is 30,000 It is estimated that there will be 10.6 million new cases of tuberculosis in the world in 2022, with an incidence rate of 133/100,000. It is estimated that there will be 10.6 million new cases of tuberculosis in the world in 2022, with an incidence rate of 133/100,000. . Among all new patients, 410,000 (3.9%) were patients with multidrug-resistant/rifampicin-resistant tuberculosis. The proportion of multidrug-resistant/rifampicin-resistant patients was 3.3% among new patients and 17% among retreated patients. Thus, multidrug-resistant tuberculosis Multidrug-resistant tuberculosis (MDR-TB) and rifampicin-resistant tuberculosis (RR-TB) remain serious problems facing global tuberculosis control. Therefore, rapid diagnosis of tuberculosis and drug-resistant tuberculosis is urgent. |
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Methods for drug resistance testing |
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Currently, Mycobacterium tuberculosis MTB Proportional susceptibility testing It is the gold standard for drug resistance detection, but the test report time is long, ranging from 4 to 8 weeks, which limits the diagnosis and treatment of the disease. GeneXpert MTB/RIF and Linear Probe Assays (LPAs) There are also problems such as expensive instruments and reagents, and the fact that the tested drugs are only first-line anti-tuberculosis drugs. Multicolor probe melting curve analysis (multicolor melting curve analysis, MMCA) MTB resistance detection technology, which has obtained many patent technologies. |
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MMCA's MTB resistance detection technology principle |
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MMCA's MTB resistance detection technology is based on the different GC contents of wild-type DNA molecules and mutant DNA molecules. Probes labeled with fluorescent groups and quenching groups at both ends are added to the PCR system. During the PCR process, a single-stranded nucleotide sequence that is complementary to the probe sequence is amplified. After the amplification is completed, a melting curve analysis process is added, and the changes in the fluorescence value are monitored in real time. By calculating the negative derivative of the fluorescence value and the temperature, the melting curve of the hybridization product of the probe and the sequence can be obtained, and the melting point (Tm value) can be obtained, thereby inferring the sequence mutation information. This method can detect four first-line anti-tuberculosis drugs and second-line fluoroquinolone (FQ) drugs, is easy to operate, has a reporting time of 3 to 4 hours, and shows high Sensitivity and Specificity . |
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Literature support In the literature referenced in this paper, the morning sputum of the same patient was cultured using BACTEC MGIT960. Proportional method and MMCA Act The drug resistance of five anti-tuberculosis drugs was detected simultaneously. For specimens with inconsistent test results by the two methods, the reference standard with the highest resolution and the most reliable results, gene sequencing, was used for verification. Finally, the clinical application value of MMCA detection in the rapid diagnosis of drug-resistant tuberculosis was evaluated. The following are some data from the literature. Based on the comprehensive test data, the sputum MMCA method directly detects the drug resistance of MTB in patients. It has good consistency with the gold standard proportional drug sensitivity test and the reference method gene sequencing technology, fast speed, high sensitivity, good repeatability, easy interpretation of results, coverage of multiple drug-resistant sites, and closed-tube operation that can greatly reduce the risk of PCR product contamination. These characteristics show that its rapid detection of drug-resistant MTB is effective and feasible, and will play an important role in the early detection, diagnosis, intervention, control of transmission, and protection of susceptible populations of tuberculosis, especially drug-resistant tuberculosis. |
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Table 1 Comparison of MMCA test of 235 morning specimens and proportional drug susceptibility test of 235 MTB isolates [1]
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It can be seen from this that Multicolor probe melting curve method Application in the detection of drug-resistant mutations in Mycobacterium tuberculosis good . |
| Products in the field of Mycobacterium tuberculosis drug resistance mutation detection |
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Products that use the multicolor probe melting curve method in the field of drug-resistant mutation detection of Mycobacterium tuberculosis in the National Medical Products Administration are mainly concentrated in Xiamen Zhishan Biotechnology Co., Ltd. Drug detection includes ethambutol, isoniazid, fluoroquinolone, streptomycin, rifampicin and related gene mutation detection. The details are as follows: |
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Qihengxing Probe Method qPCR Mix Product List |
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