To Study The Relationship Between Drug-resistance Gene Mutation And Drug-resistance Level In M. Tuberculosis Isolated From Yantai Region

Objective: The present study is to report the KatG, rpoB, rpsL genes mutation in 71clinical isolatedstrains of MTB in Yantai, and to analyze the relationship of genemutation and drug resistance inmycobacterium tuberculosis(MTB)., and to evaluate its clinical significance. Methods: 71 M.tuberculosis clinical isolated strains from sputum specimens of 71 lung tuberculosis patientsfrom2004.3to2004.9.The reference strain M. t uberculosis H37 Rv from National institute for the controlof pharmaceutical and biological products. sputum specimens was grown with Bactec-960.some culturefor traditional drug susceptibility tests, some culture for DNA extraction. The DNA of M. tuberculosisH37Rv and the 71clinical isolates was amplified by the primers katG, rpsLe and rpoB. The PCRamplification product was analyzed by SSCP(single stranded conformation polymorphism), With thereference of M. tuberculosis strain H37RV was used as control, the type of genemutation can be detected.Results:â‘ In 71 M. t uberculosis clinical isolated strains, SM,INH and RFP resistance isolated strainswere 56, 55 and 58。②The PCR products of katG gene, rpsL gene and rpoB gene presented a clear 282bp band,267 bp band and 213 bp band on 20g/L agarose gel, respectively.â‘¢In 56 SM resistance isolatedstrains, 40 displayed different SSCP patterns from M. tuberculosis H₃₇ Rv strain. In 55 INH resistanceisolated strains, 37 displayed different SSCP patterns from M. tuberculosis H₃₇ Rv strain. In 58 RFPresistance isolated strains, 45 displayed different SSCP patterns from M. tuberculosis H₃₇ Rv strain. Thegenemutation rate of RFP,INH and SM resistance isolated strains were 71.4ï¼…,66.7ï¼…and 77.6ï¼…respectively, and the mutation rate of RFP,INH and SM high concentration resistance isolated strainswas92.5ï¼…,78.7ï¼…and 87.8ï¼…, respectively. But the mutation rate of low level resistance strains was44.4ï¼…,12.5ï¼…and 26.7ï¼….Conclusions In this study, drug resistance of Mycobacterium tuberculosisin yantai Was caused mainlyby gene mutation, the genemutation rate of RFP,INH,SM was in relation with drug resistance level of M.Tuberculosis.The genemutation rate w as higher in high concentration drug resistance isolated strains thanthat in low concentration drug resistance isolated strains.