The Research On Genotyping And Drug Resistance Of Retreated Tuberculosis In Beijing

1.Analysis of drug resistance and mutation profiles in Mycobacterium tuberculosis isolates in a surveillance in BeijingObjective:This study aims to analyze drug resistance and mutations profiles in Mycobacterium tuberculosis(MTB)isolates in a surveillance site in Beijing(Huairou District).Methods:The proportion method was used for determining drug resistance profiles against four first-line and seven second-line anti-TB drugs.Molecular line probe assays were used for rapid detection of resistance to RFP and INH.Results:Among 235 strains of Mycobacterium tuberculosis,79(33.6%)isolates were resistant to one or more drugs.There were 18 mono resistant tuberculosis cases(7.7%),19 poly-resistant cases(8.1%),28 RIF-resistant cases(11.9%),24 MDR cases(10.2%),7 Pre-XDR cases(3.0%)and 2 XDR cases(0.9%).A higher MDR-TB proportion was detected in retreatment cases than in new cases(34.5%vs.6.8%,p<0.05).The majority(62.5%)of RIF resistant isolates exhibited mutation at S531L in the rpoB gene.62.9%INH resistant isolates had mutation at S315T1 in the katG gene.Conclusion:The multidrug resistance(MDR)rate of Mycobacterium tuberculosis isolated from retreated patients in Beijing TB surveillance site was significantly higher than that of newly treated patients.Therefore,detailed drug-testing results are crucial.Detection of common genetic mutations in drug-resistant strains can quickly and accurately diagnose MDR,which will also improve patient treatment outcomes and reduce transmission rates.2.Study on drug resistance of retreated tuberculosis in BeijingObjective:To understand the drug resistance of tuberculosis in retreated patients in Beijing.Methods:An investigation was conducted on retreated pulmonary tuberculosis patients in Beijing from January 2017 to December 2019.Through the comparison of the strain database information,the first and last registered Mycobacterium tuberculosis strains from the same patient were found to be paired.There were 134 pairs of strains in 268 cases,and the molecular line probe method was used to quickly detect the resistance to RFP and INH.Proportional drug sensitivity test was performed on the last isolated strains of retreated patients.Results:The proportion of INH resistant strains in the initial isolates of retreated patients in Beijing was 9.0%,which was higher than the proportion of INH resistant strains in the last isolate(X2=4.254,P<0.05).The MDR rate was 29.9%(40/134)in retreated patients,and 23.1%(18/78)in recurrent patients.Among retreated patients,the MDR rate of non-recurrent patients was higher than that of recurrent patients(X2=4.090,P<0.05).A total of 14 patients(10.4%)had drug resistance changes,of which 10 patients(71.4%)changed from sensitive to resistant,and 4 patients(28.6%)changed from resistant to sensitive.Among the resistant strains,the majority(63.0%)of RIF resistant isolates exhibited mutation at S531L in the rpoB gene.70.5%INH resistant isolates had mutation at S315T1 in the katG gene.The proportional method drug susceptibility results showed that any drug resistance rate in recurrent patients was 57.7%,and any drug resistance rate in non-recurrent patients was 53.1%.Conclusion:The proportion of INH resistant isolates in the initial isolates of retreated patients in Beijing was higher than that of the last isolates,and the MDR rate of non-recurrent retreated patients was higher than that of recurrent patients.Once tuberculosis is diagnosed clinically,it should be taken immediately,multi-drug combination,standardized medication,adherence to treatment.It cannot be interrupted to prevent the development of drug-resistant tuberculosis or even MDR tuberculosis.3.Genotyping analysis of patients with retreated tuberculosis in BeijingObjective:To understand the cause of the disease by comparing the genotype of the strain before and after retreatment of tuberculosis patients in Beijing.Then take the last strain of retreated patients as the research object to understand the strain genotype and clustering characteristics of Mycobacterium tuberculosis in retreated patients in Beijing.Methods:Taking patients with retreated pulmonary tuberculosis in Beijing from January 2017 to December 2019 as the research object,the RD105 gene deletion method and the 15 locus variable number tandem repeat genotyping experiment were used to compare the genotypes of Mycobacterium tuberculosis before and after retreatment of pulmonary tuberculosis patients,so as to determine the cause of tuberculosis recurrence.Taking the last strain of retreated tuberculosis patients as the research object,the genotyping technology was evaluated for the distinguishing ability of Mycobacterium tuberculosis in retreated patients in this area,and the phylogenetic analysis of Mycobacterium tuberculosis prevalent in retreated patients was evaluated.To conduct research to master the genetic characteristics of Mycobacterium tuberculosis in retreated patients.Results:The proportion of relapse in retreated patients was 75.4%(101/134),and the proportion of exogenous reinfection was 24.6%(33/134).The proportion of relapse in recurrent patients with tuberculosis was 65.4%(51/78),the proportion of exogenous reinfection was 34.6%(27/78).The proportion of acquired drug resistance was 60%(6/10),and the proportion of primary drug resistance was 40%(4/10).Among the 134 cases of Mycobacterium tuberculosis strains isolated from retreatment patients,126 cases were Beijing type and 8 cases were non-Beijing type.134 strains of Mycobacterium tuberculosis showed 110 genotypes,including 2 clonal complexes and 25 idiotypes.The 33 strains formed 9 clusters,and the clustering rate was 17.9%.Conclusion:The main reason for the onset of retreatment tuberculosis in Beijing was relapse,and there were also small-scale epidemics,and the main epidemic strains were Beijing genotypes,showing high genetic diversity.4.Application of whole genome sequencing in multidrug-resistant Mycobacterium tuberculosisObjective:To understand the genetic lineage and transmission relationship of clinical isolates from patients with retreatment MDR through whole-genome sequencing(WGS),and to predict the drug resistance of 16 drugs in the whole genome of each MTB strain.Methods:From January 2017 to December 2019 in Beijing,40 cases of MDR strains of retreated patients were detected by molecular drug resistance line probe assay,and the tuberculosis genome were extracted by the improved CTAB method.WGS master the lineage characteristics and transmission relationship of MDR TB.WGS also analyze the mutation of each drug resistance site through the comparison information,and predict the drug resistance based on the mutation and drug resistance relationship in the database.Results:Among 40 strains identified as MDR by the line probe assay,WGS showed that 1 was a rifampicin-sensitive strain.The 40 cases of MTB were all lineage 2,of which there were 33 sub-lineages L2.2.1 and 7 L2.2.2.29(72.5%,29/40)were"modern" Beijing type,and 11(27.5%,11/40)were "old" Beijing type.Two of the 40 MTB cases clustered.A total of 16 genes related to drug resistance were found,and 11 MTB strains had two or more drug resistance genes for the same anti-tuberculosis drug.Conclusion:MDR isolates from retreated tuberculosis patients in Beijing were mainly lineage 2,"modern" Beijing type accounted for the majority.Detection of mutations related to drug resistance can predict drug resistance.