Line probe assay for detection of katG gene mutations associated with Mycobacterium tuberculosis resistance to INH

Objective To detect the katG gene resistant to isoniazid in Mycobacterium tuberculosis by LiPA and evaluate the feasibility of clinical application of the LiPA technique.Methods There 80 clinical isolates was detected by L-J cultivation to determine drug resistance and the PCR amplified katG genes by DNA sequence.Simultaneously,LiPA was detected the mutation of katG in Mycobacterium tuberculosis isolates.These three assays were compared to evaluate the accuracy of LiPA technique.Results The 80 clinical isolates including 35 strains sensitive to INH and 45 strains resistant to INH.katG was successfully amplified from 100% of the susceptible strains and 91.1%(41/45)resistant strains.4 of 45 INH resistant isolates katG was deleted.katG 315 codon mutations were observed in 26 of 41 katG at sites of 315 ACC(Thr,25/41),ATC(Ile,1/41).The mechanisms of katG analyzed by LiPA we prepared were identical to katG sequencing.Conclusion The LiPA technique for determination of Mycobacterium tuberculosis resistant to INH is specific,sensitive and can be used as a routine in clinical laboratory.