Isolate Of Extensively Drug-Resistant Tuberculosis And The Initial Analysis Of The Durg Resistance Mechanism For These Clinical Isolates

Objective Screen Extensively Drug-Resistant Tuberculosis(XDR-TB) clinical isolates and initial analyse the roles of the two major mechanism for durg resistance of those XDR-TB isolates.Methods Use the Lowenstein-Jensen drug susceptibility technology to detecte drug susceptibility of MTB clinical isolates to screen XDR-TB isolates; Extract the genomic DNA of totally XDR-TB strains isolated from Shanghai Pulmonary Hospital and detect the genetic mutations in the corresponding resistance genes and 15 SNPs uniqued to XDR-TB clinical isolate KZN605 which reported by The Broad Institute in USA with DNA sequencing followed by PCR;Test the changes of Minimal Inhibition Concentration(MIC) of the XDR-TB isolates to durgs after added efflux pump inhibitors (verapamil, CCCP and reserpine).,and comprae the expression of genes coded efflux pump stimulated by drugs with not stimulated.Results The mutation of rpoB, katG and rpsL occurred in all XDR-TB strains. The mutation of gyrA, gyrB, rrs, ahpC, inhA and embB occurred in 9 strains, 2strains, 6strains,2strains, 3strains and 4strains respectively. There is no mutation of tlyA in all strains. Most of SNPs of the KZN-605 strain weren't occurred in all strains. Most of all strains have no significant changes of MICs except for one strain whose MIC of ofloxacin decreased by 16 times after added efflux pump inhibitors. The gene Rv2686 encoding ATP-binding cassette(ABC) transporter over express under the press of OFLX.Conclusions most of the 15 SNPs of the KZN-605 strain may be irrelevant to XDR-MTB,The genetic mutations in the corresponding resistance genes is the key mechanism for the clinical isolated of XDR-TB and the ABC transporter play a role partly in determining the resistance to Fluoroquinolones, the mutations of D500N and A1427G mediated drug resistance to XDR-TB isolates need more study.