ABSTRACT
ObjectiveTo analyze the characterstics of phenotype and genotype of multidrug resistant tuberculosis (MDR-TB) and extensively drug resistant tuberculosis (XDR-TB) by molecular line probe assay and liquid culture with MGIT960.MethodsGenoType MTBDR Kits were used for identifying the types of the first-line and second-line antituberculosis drug resistant genes partly and BD MGIT960 was used for detecting the chug susceptibility.Results( 1 ) Out of 94 MDR-TB strains,the rate of drug resistant to EMB,AMK,OFX and MFX by BD MGIT960 assay were 36.2%,17.0%,54.3% and 55.3%,respectively.Among these isolates,13 were extensively drug resistant tuberculosis (XDR-TB).(2) Compared with MGIT960,the concordance rate of GenoType MTBDRplus was 86.2% and 95.7% respectively.Taking MGIT960 results as reference,the sensitivity of GenoType MTBDRsl detecting the susceptibility of EMB,AMK,OFX and MFX to 94 isolates were 47.1%,81.3%,94.1%,94.2%,respectively.The specificity were 75.0%,98.7%,90.7%,92.9%,respectively.(3) Among the rpoB mutation categories,S531L accounts for most.MTB resistant to IFN caused by the mutation of katG chiefly and the S315T1 was in the majority.The gyrA mutation sites located at the ninety-fourth codon most.Out of 94 strains,23 were mixed with 2 kindsof Mycobacterium tuberculosis at least and 7 were undetectable mutations.Conclusion Among the M/XDR-TB,the strains resistant to INH,RFP,AMK,OFX and MFX were caused most by the mutation of katG,rpoB,rrs and gyrA,respectively.The relationship between EMB and embB was not so clear relatively.As a fast detecting drug susceptibility test kit,GenoType MTBDR possess good sensitivity and specificity.So,it could be as an assistant method to guide the therapy on clinic.