Objective Tuberculosis remains a severe public health issue, and the Beijing family of mycobacterium tuberculosis （M. tuberculosis） is widespread in East Asia, especially in some areas in China, like Beijing and Tia...Objective Tuberculosis remains a severe public health issue, and the Beijing family of mycobacterium tuberculosis （M. tuberculosis） is widespread in East Asia, especially in some areas in China, like Beijing and Tianjin. This study aimed at determining the mutation patterns of drug-resistant Beijing strains of M. tuberculosis isolated from Tianjin, China. Methods A total of 822 M. tuberculosis isolates were screened for drug resistance by an absolute concentration method and the genotype was identified by PCR. 169 drug-resistant isolates of the Beijing family were analyzed for the potential mutations in the rpoB, katG, inhA promoter region and in rpsL, rrs and embB genes, which are associated with resistance to rifampin （RFP）, isoniazid （INH）, streptomycin （SM） and ethambutol （EMB） respectively by PCR and DNA sequencing. Results Fifty-eight out of 63 RFP-resistant isolates were found to carry the mutations within the 81-bp RFP resistance determining region （RRDR） of the rpoB gene and the most frequent mutations occurred at codon 531 （44.4%）, 526 （28.6%）, and 516 （7.9%） respectively. 16 mutation pattems affecting 12 different codons around the RRDR of rpoB were found. Of 116 INH-resistant isolates, 56 （48.3%） had the mutation of katG 315 （AGC→ACC） （Ser→Thr）, 3 （2.6%） carried S315N （AGC→AAC） and 27 （16.0%） had the mutation of inhA-15A→T. 84 out of 122 SM-resistant isolates （68.9%） displayed mutations at the codons 43 or 88 with AAG→AGG （Lys→Arg） of the rpsL gene and 22 （18.0%） with the mutations at positions 513A→C, 516C→T or 905 A→G in the rrs gene. Of 34 EMB-resistant isolates, 6 had mutation with M306V （ATG→GTG）, 3 with M306I （ATG→ATT）, 1 with M306I （ATG→ATA）, 1 with D328Y （GAT→TAT）, 1 with V348L （GTC→CTC）, and 1 with G406S （GGC→AGC） in the embB gene. Conelusion These novel findings extended our understanding of resistance-related mutations in the Beijing strains of M. tuberculosis and may provide a scientific basis for development of new strategies for diagnosis and control of tuberculosis in China and other countries where Beijing strains are prevalent.展开更多
Background:Drug resistant tuberculosis poses a great challenge for tuberculosis control worldwide.Timely determination of drug resistance and effective individual treatment are essential for blocking the transmission ...Background:Drug resistant tuberculosis poses a great challenge for tuberculosis control worldwide.Timely determination of drug resistance and effective individual treatment are essential for blocking the transmission of drug resistant Mycobacterium tuberculosis.We aimed to establish and evaluate the accuracy of a reverse dot blot hybridization(RDBH)assay to simultaneously detect the resistance of four anti-tuberculosis drugs in M tuberculosis isolated in China.Methods:In this study,we applied a RDBH assay to simultaneously detect the resistance of rifampicin(RIF),isoniazid(INH),streptomycin(SM)and ethambutol(EMB)in 320 clinical M.tuberculosis isolates and compared the results to that from phenotypic drug susceptibility testing(DST) and sequencing.The RDBH assay was designed to test up to 42 samples at a time.Pearson's chi-square test was used to compute the statistical measures of the RDBH assay using the phenotypic DST or sequencing as the gold standard method,and Kappa identity test was used to determine the consistency between the RDBH assay and the phenotypic DST or sequencing.Results:The results showed that the concordances between phenotypic DST and RDBH assay were 95%for RIF,92.8%for INH,84.7%for SM,77.2%for EMB and the concordances between sequencing and RDBH assay were 97.8%for RIF,98.8%for INH,99.1%for SM,93.4%for EMB.Compared to the phenotypic DST results,the sensitivity and specificity of the RDBH assay for resistance detection were 92.4 and 98.5%for RIF,90.3 and 97.3%for INH,77.4 and 91.5%for SM,61.4 and 85.7%for EMB,respeaively;compared to sequencing,the sensitivity and specificity of the RDBH assay were 97.7 and 97.9%for RIF,97.9 and 100.0% for INH,97.8 and 1OO.O% for SM,82.6 and 99.1%for EMB,respectively.The turnaround time of the RDBH assay was 7 h for testing 42 samples.Conclusions:Our data suggested that the RDBH assay could serve as a rapid and efficient method for testing the resistance of M. tuberculosis against RIF,INH,SM and EMB,enabling early administration of appropriate treatment regimens to the affected drug resistant tuberculosis patients.展开更多
基金supported by National Science Key Grant(2008ZX10003-009).
文摘Objective Tuberculosis remains a severe public health issue, and the Beijing family of mycobacterium tuberculosis （M. tuberculosis） is widespread in East Asia, especially in some areas in China, like Beijing and Tianjin. This study aimed at determining the mutation patterns of drug-resistant Beijing strains of M. tuberculosis isolated from Tianjin, China. Methods A total of 822 M. tuberculosis isolates were screened for drug resistance by an absolute concentration method and the genotype was identified by PCR. 169 drug-resistant isolates of the Beijing family were analyzed for the potential mutations in the rpoB, katG, inhA promoter region and in rpsL, rrs and embB genes, which are associated with resistance to rifampin （RFP）, isoniazid （INH）, streptomycin （SM） and ethambutol （EMB） respectively by PCR and DNA sequencing. Results Fifty-eight out of 63 RFP-resistant isolates were found to carry the mutations within the 81-bp RFP resistance determining region （RRDR） of the rpoB gene and the most frequent mutations occurred at codon 531 （44.4%）, 526 （28.6%）, and 516 （7.9%） respectively. 16 mutation pattems affecting 12 different codons around the RRDR of rpoB were found. Of 116 INH-resistant isolates, 56 （48.3%） had the mutation of katG 315 （AGC→ACC） （Ser→Thr）, 3 （2.6%） carried S315N （AGC→AAC） and 27 （16.0%） had the mutation of inhA-15A→T. 84 out of 122 SM-resistant isolates （68.9%） displayed mutations at the codons 43 or 88 with AAG→AGG （Lys→Arg） of the rpsL gene and 22 （18.0%） with the mutations at positions 513A→C, 516C→T or 905 A→G in the rrs gene. Of 34 EMB-resistant isolates, 6 had mutation with M306V （ATG→GTG）, 3 with M306I （ATG→ATT）, 1 with M306I （ATG→ATA）, 1 with D328Y （GAT→TAT）, 1 with V348L （GTC→CTC）, and 1 with G406S （GGC→AGC） in the embB gene. Conelusion These novel findings extended our understanding of resistance-related mutations in the Beijing strains of M. tuberculosis and may provide a scientific basis for development of new strategies for diagnosis and control of tuberculosis in China and other countries where Beijing strains are prevalent.
文摘Background:Drug resistant tuberculosis poses a great challenge for tuberculosis control worldwide.Timely determination of drug resistance and effective individual treatment are essential for blocking the transmission of drug resistant Mycobacterium tuberculosis.We aimed to establish and evaluate the accuracy of a reverse dot blot hybridization(RDBH)assay to simultaneously detect the resistance of four anti-tuberculosis drugs in M tuberculosis isolated in China.Methods:In this study,we applied a RDBH assay to simultaneously detect the resistance of rifampicin(RIF),isoniazid(INH),streptomycin(SM)and ethambutol(EMB)in 320 clinical M.tuberculosis isolates and compared the results to that from phenotypic drug susceptibility testing(DST) and sequencing.The RDBH assay was designed to test up to 42 samples at a time.Pearson's chi-square test was used to compute the statistical measures of the RDBH assay using the phenotypic DST or sequencing as the gold standard method,and Kappa identity test was used to determine the consistency between the RDBH assay and the phenotypic DST or sequencing.Results:The results showed that the concordances between phenotypic DST and RDBH assay were 95%for RIF,92.8%for INH,84.7%for SM,77.2%for EMB and the concordances between sequencing and RDBH assay were 97.8%for RIF,98.8%for INH,99.1%for SM,93.4%for EMB.Compared to the phenotypic DST results,the sensitivity and specificity of the RDBH assay for resistance detection were 92.4 and 98.5%for RIF,90.3 and 97.3%for INH,77.4 and 91.5%for SM,61.4 and 85.7%for EMB,respeaively;compared to sequencing,the sensitivity and specificity of the RDBH assay were 97.7 and 97.9%for RIF,97.9 and 100.0% for INH,97.8 and 1OO.O% for SM,82.6 and 99.1%for EMB,respectively.The turnaround time of the RDBH assay was 7 h for testing 42 samples.Conclusions:Our data suggested that the RDBH assay could serve as a rapid and efficient method for testing the resistance of M. tuberculosis against RIF,INH,SM and EMB,enabling early administration of appropriate treatment regimens to the affected drug resistant tuberculosis patients.
