title: [Quantitative analysis of mRNA as a marker for viability of Mycobacterium tuberculosis].
abstract: OBJECTIVE
  To study whether quantitative analysis of M. tuberculosis mRNA could be used to assess bacterial viability.
  
  
  METHODS
  The levels of M. tuberculosis mRNA were compared 24, 48, and 72 hours after M. tuberculosis H(37)R(V) was treated with no drug, 1.0 micro g/ml and 10.0 micro g/ml rifampicin, 0.2 micro g/ml and 1.0 micro g/ml isoniazid, 2 micro g/ml and 4 micro g/ml ethambutol, 2 micro g/ml and 4 micro g/ml streptomycin, 1.25 micro g/ml and 5.00 micro g/ml ofloxacin. The levels of mRNA were determined by quantitative PCR.
  
  
  RESULTS
  After exposure to isoniazid, rifampicin, and streptomycin for 24 h, the level of M. tuberculosis H(37)R(V) was reduced markedly. Similarly, after exposure to isoniazid, streptomycin, ethambutol, and ofloxacin for 72 h, the level of M. tuberculosis H(37)R(V) was identical, but higher than that after exposure to rifampicin. Exposure of M. tuberculosis H(37)R(V) to rifampicin for 24 h reduced the levels of 85B mRNA to 0.02% of the control; exposure to other drugs for 24 h reduced the levels to 1% approximately 10% of the control, and for 72 h to less than 1% of the control.
  
  
  CONCLUSIONS
  The levels of mRNA can show the difference between M. tuberculosis H(37)R(V) exposed and unexposed to drugs, and are consistent with colony forming unit. mRNA could be used as a marker for assessing the viability of M. tuberculosis.
authors.affiliation: 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: Lian-shan
authors.initials: LS
authors.lastname: Duan
authors.forename: Gui-fang
authors.initials: GF
authors.lastname: Liang
authors.forename: Miao
authors.initials: M
authors.lastname: Tian
mesh_terms: D015415:Biomarkers; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D016133:Polymerase Chain Reaction; D012329:RNA, Bacterial / Q000032:analysis*; D012333:RNA, Messenger / Q000032:analysis*; D012293:Rifampin / Q000494:pharmacology; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012293:Rifampin