Research On Measurement Of Viability, Susceptibility Test To Rifampin And Monitoring Response To Chemotherapy Using By Quantitative Analysis Of Mycobacterium Tuberculosis MRNA

Objective To study whether quantitative analysis of Mycobacterium tuberculosis mRNA could be used to assess bacterial viability, to evaluate the significance of susceptibility of M. tuberculosis strains to rifampin and monitoring response to chemotherapy using by quantitative analysis of M. tuberculosis mRNA.Methods (1) Compared the levels of mRNA after 24, 48, 72 hours that M. tuberculosis H37Rv were treated with no drugs, rifampin isoniazid, ethambutol. streptomycin and ofloxacin. The levels of mRNA were determined by quantitative RT-PCR. (2) 29 rifampin resistant strains and 23 rifampin sensitive strains were test their susceptibility to rifampin by quantitative analysis of M. tuberculosis mRNA. (3) Quantitative measurement of sputum M. tuberculosis mRNA from 15 smear-positive pulmonary tuberculosis patients receiving an optimal drug treatment regimens. Results (1) Exposure of M. tuberculosis H37Rv to rifampin for 24h reduced the levels of 85BmRNA to 0.02%, exposure to other drugs for 24h reduced to 1%-10%, for 72h reduced to < 1%. (2) The agreement of quantitative analysis of M. tuberculosis mRNA with absolute concentration method was 69.8%, 84.9%, 92.5% respectability when rifampin 1μg/ml, 2μg/ml, 4μg/ml and 1% proportion was, 81.1%, 92.5%, 92.5% when 10% proportion was.Compared with absolute concentration method , the sensitivity of quantitative analysis of M. tuberculosis mRNA was >90%,the specialty was 87.5% when rifampin 2μg/ml and 10% proportion was.(3) The rapid decline of mRNA in sputum during the first two days of effective treatment,by day 14 of treatment , 12 of 15 subjects had no detectable mRNA ,by day 60 of treatment ,all subjects had no detectable mRNA in their sputum.Conclusions (1) The levels of mRNA were shown the differences exposure to drugs with no drug , and nearly parallel with CFU. mRNA is a marker for viability of M.tuberculosis. (2) Quantitative analysis of M. tuberculosis mRNA was a rapid, sensitive method in rifampin resistance screening , and showed mRNA declined to 10% of control when rifampin 2μg/ml was as rifampin- sensitive strains, otherwise as rifampin-resistant strains . (3) The rapid disappearance of M.tuberculosis mRNA from sputum suggests that it is a good indicator of microbial viability and a useful marker for rapid assessment of response to chemotherapy.