| Objective To rapidly identify drug-resistant Mycobacterium tuberculosis using phenotypic and genotypic methods and to evaluate the clinical significance of rapid phenotypic susceptibility test by PhaB assay .Methods (1) We tested 90 INH-resistant strains,62 INH-susceptible strains;91 RFP-resistant strains ,50 RFP-susceptible strains;75 OFLX-resistant strains and 58 OFLX-susceptible strains by PhaB assay.(2) DNA sequencing , PCR-SSCP and PhaB were performed on the 91 RFP-resistant strains(including 82 MDR-TB strains) , 42 RFP-susceptible strains,75 OFLX-resistant strains and 40 OFLX-susceptible strains. Results (1) For the detection of INH susceptibility by PhaB assay, the accordance of PhaB with absolute concentration method was 93% (141/152), the sensitivity of PhaB assay was 92%(83/90) and the speciality of PhaB assay was 94%(58/62); For the detection of RFP susceptibility, the accordance ,sensitivity and speciality were 93 %(131/141), 92 % (84/91) and 94%(47/50) respectively; For the detection of OFLX susceptibility, the accordance ,sensitivity, speciality were 94%(125/133), 95%(71/75) and 93%(54/58) respectively. (2) The results obtained using DNA sequencing,PCR-SSCP and PhaB assay were compared with the absolute concentration method. For detecton RFP,the accordance,sensitivity and speiciality of PhaB were 93%,92% and 95%; ,the accordance,sensitivity and speiciality of DNA sequencing were 93%,87% and 100%; ,the accordance,sensitivity and speiciality of PCR-SSCP were9n%,86% and 100%.For detection OFLX, ,the accordance,sensitivity and speiciality of PhaB assay were 95%,95% and 95 %; ,the accordance,sensitivityand speiciality of DNA sequencing were 80%,71% and 98 % ,the accordance,sensitivity and speiciality of PCR-SSCP were 75%,63% and98%. Conclusion PhaB assay is a low-cost, rapid, sensitive method and has high accordance with absolute concentration technology. It can obtain the drug susceptibility tests results within 48-96h ,and have a good perspective in clinical laboratory.
|
PDF Full Text Request