title: [Susceptibility test to rifampin by using quantitative analysis of Mycobacterium tuberculosis mRNA].
abstract: OBJECTIVE
  To evaluate the significance of quantitative analysis of Mycobacterium tuberculosis mRNA in the test of susceptibility of Mycobacterium tuberculosis strains to rifampin.
  
  
  METHODS
  The susceptibility to rifampin of fifty-three clinical isolated strains was test by the percentage of Mycobacterium tuberculosis 85B mRNA copies before and after the use of rifampin, and 1% and 10% were used as the standards for drug resistance, which was compared with the absolute concentration method. Among them, 29 were rifampin resistant strains and 24 rifampin sensitive strains.
  
  
  RESULTS
  When the concentration of rifampin was 1 micro g/ml, and 1% and 10% were used as the standards, the accuracy of quantitative analysis of Mycobacterium tuberculosis mRNA with the absolute concentration method was 70% and 81% respectively, and the sensitivity of quantitative analysis of Mycobacterium tuberculosis mRNA was 100% and 100% respectively, while the specificity of quantitative analysis of Mycobacterium tuberculosis mRNA was 33% and 58%. When the concentration of rifampin was 2 micro g/ml, the accuracy of quantitative analysis of mRNA with the absolute concentration method was 85% and 93% respectively, and the sensitivity was 100% and 97% respectively, while the specificity was 67% and 88% respectively. When the concentration of rifampin was 4 micro g/ml, the accuracy was 93% and 93%, and the sensitivity was 93% and 93%, while the specificity was 92% and 92%.
  
  
  CONCLUSIONS
  Quantitative analysis of Mycobacterium tuberculosis mRNA was a rapid, sensitive method in rifampin resistance screening. We suggest that the critical concentration of rifampin be 2 micro g/ml, and the critical proportion of mRNA copy be 10%.
authors.affiliation: Department of Basic Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing 101149, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Lu
authors.forename: Li-zhen
authors.initials: LZ
authors.lastname: Zhu
authors.forename: Nai-hui
authors.initials: NH
authors.lastname: Chu
authors.forename: Lian-shan
authors.initials: LS
authors.lastname: Duan
authors.forename: Gui-fang
authors.initials: GF
authors.lastname: Liang
mesh_terms: D000904:Antibiotics, Antitubercular / Q000494:pharmacology*; D015415:Biomarkers; D004351:Drug Resistance / Q000235:genetics*; D008826:Microbial Sensitivity Tests / Q000379:methods; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012293:Rifampin / Q000494:pharmacology*; D012680:Sensitivity and Specificity; D018088:Tuberculosis, Multidrug-Resistant / Q000382:microbiology
chemical_list: D000904:Antibiotics, Antitubercular; D015415:Biomarkers; D012333:RNA, Messenger; D012293:Rifampin