ABSTRACT
Objective To understand the genotype distribution of Mycobacterium tuberculosis and the drug susceptibility of M.tuberculosis with different genotypes in Changping district of Beijing and evaluate the application of genotyping of M.tuberculosis in local tuberculosis (TB) prevention and control.Methods A total of 1 099 M.tuberculosis strains isolated in Changping from 2011 to 2015 were used.Spoligotyping and 12-locus VNTR recommended by Gao were used for the genotyping of these isolates.In addition,the susceptibility of the M.tuberculosis isolates to rifampin (RFP),isoniazid (INH),ethambutol (EMB),streptomycin (SM),amikacin (AMK) and ofloxcin (OFX) were detected by using conventional drug susceptibility test.Results From 2011 to 2015,the detection rate of OFX-resistance increased from 2.9％ to 8.9％ (P=0.01).Of all the M.tuberculosis isolatcs,976 belonged to Beijing genotype (88.8％),and the other 123 belonged to non-Beijing genotype (11.2％).In addition,there were 189 ancient Beijing genotype isolates and 787 modern Beijing genotype isolates,respectively.The proportion of Beijing genotype strains showed no significant increase in the past five years (81.1％ in 2011 vs.82.0％ in 2015).On the basis of VTNR genotyping,only 2 isolates belonged to one cluster (0.1％).In addition,the AMK resistant rate of Beijing genotype strains (1.7％)was significantly lower than that of non-Beijing genotype strains (4.9％,P=0.02).Compared with modern Beijing genotype strains,the SM resistant rate of ancient Beijing genotype strains was significantly higher (28.0％ vs.15.7％,P=0.01).Conclusions In the past five years,the OFX-resistant rate of M.tuberculosis in Changping was in increase.There was no significant difference in the detection of Beijing genotype strains during this period.In addition,the low clustering rate indicated that the TB transmission rate was low in Changping.
ABSTRACT
Objective To understand the genotype distribution of Mycobacterium tuberculosis and the drug susceptibility of M.tuberculosis with different genotypes in Changping district of Beijing and evaluate the application of genotyping of M.tuberculosis in local tuberculosis (TB) prevention and control.Methods A total of 1 099 M.tuberculosis strains isolated in Changping from 2011 to 2015 were used.Spoligotyping and 12-locus VNTR recommended by Gao were used for the genotyping of these isolates.In addition,the susceptibility of the M.tuberculosis isolates to rifampin (RFP),isoniazid (INH),ethambutol (EMB),streptomycin (SM),amikacin (AMK) and ofloxcin (OFX) were detected by using conventional drug susceptibility test.Results From 2011 to 2015,the detection rate of OFX-resistance increased from 2.9％ to 8.9％ (P=0.01).Of all the M.tuberculosis isolatcs,976 belonged to Beijing genotype (88.8％),and the other 123 belonged to non-Beijing genotype (11.2％).In addition,there were 189 ancient Beijing genotype isolates and 787 modern Beijing genotype isolates,respectively.The proportion of Beijing genotype strains showed no significant increase in the past five years (81.1％ in 2011 vs.82.0％ in 2015).On the basis of VTNR genotyping,only 2 isolates belonged to one cluster (0.1％).In addition,the AMK resistant rate of Beijing genotype strains (1.7％)was significantly lower than that of non-Beijing genotype strains (4.9％,P=0.02).Compared with modern Beijing genotype strains,the SM resistant rate of ancient Beijing genotype strains was significantly higher (28.0％ vs.15.7％,P=0.01).Conclusions In the past five years,the OFX-resistant rate of M.tuberculosis in Changping was in increase.There was no significant difference in the detection of Beijing genotype strains during this period.In addition,the low clustering rate indicated that the TB transmission rate was low in Changping.
ABSTRACT
Objective To establish a rapid method to detect mutations in rpoB genes of rifampin-resistant Mycobacterium tubereulosis in dinical specimens using Real-time fluorescence PCR molecular beacon assay.Methods 174 strains of Mvcobacterium tuberculosis clinical isolates were analyzed using real-time fluorescence PCR molecular beacon assay foilowed with DNA sequencing while 12 strains of NTM and 4 strains of bacteria other than Mycobacterium tuberculosis were used as the contrast.Results Eighty-two 89.1 of 92 rifampin (RIF)-resistant strains and 3 of 82 RIF-sensitive strains were found to harbor mutation in the rpoB gene using real-time fluorescence PCR-molecular beacon assay.The specificity, sensitivity,and accuracy of this assay were 96.3%,89.1%,and 92.5%,respectively-Eithty-three of 92 RIF-resistant strains and 1 of 82 RIF-sensitive strains were found to harbor mutation in the rpoB gene using the direct DNA sequencing.The specificity,sensitivity,and accuracy of the direct DNA sequencing were 98.8,90.2%,and 94.2%,respectively.As compared with real-time PCR molecular beacon assay,171 of 174(98.3%)strains of myeobactefium tuberculosis clinical isolates had the salne results.Conclusion Real-time fluorescence PCR-molecular beacon assay can be used as a rapid screen method to detect RIF-resistant isolates.