Background The Xpert MTB/RIF showed high sensitivity and specificity in previous studies carried out in different epidemiological and geographical settings and patient populations in high-burden tuberculosis （TB） co...Background The Xpert MTB/RIF showed high sensitivity and specificity in previous studies carried out in different epidemiological and geographical settings and patient populations in high-burden tuberculosis （TB） countries.However,there were little data obtained by validation or demonstration study of the assay in China.In this study,the performance of Xpert MTB/RIF was investigated in two county-level laboratories in Hunan Province,China.Methods Consecutive patients with suspected pulmonary tuberculosis （PTB） and suspicion for multidrug-resistant tuberculosis （MDR-TB） were enrolled.For each patient suspected to have PTB,three sputum specimens （one spot sputum,one night sputum,and one morning sputum） were collected and each sputum was tested with smear microscopy,L（o）wenstein-Jensen （LJ） culture,and Xpert MTB/RIF test.For comparison across subgroups and testing methods,95％ confidence intervals were calculated.All analyses were done with SPSS 16.0,and P ＜0.05 was regarded as significant.Results For case detection,the sensitivity of Xpert MTB/RIF was 100％ for smear-and culture-positive TB and 88.6％ for smear-negative and culture-positive TB; the overall sensitivity was 94.5％ for all culture-positive patients.The specificity was 99.8％.The sensitivity of Xpert MTB/RIF assay was 22.0％ in clinical TB patients and the specificity reached 100.0％ in the group of patients who are infected with nontuberculous mycobacteria.For the detection of rifampin resistance,the sensitivity of MTB/RIF RIF-resistance detection was 92.9％,and the specificity was 98.7％.Of the 26 Xpert MTB/RIF-positive and RIF-resistant patients confirmed by LJ proportion tests,20 （76.9％） patients were infected by MDR-TB.Conclusions The Xpert MTB/RIF assay is a highly sensitive and specific method for diagnosis of TB and RIF resistance,which will enable it to have the potential to be used in county-level laboratories and lead to the reduction of the infectious pool and improvements in TB control in China.Further evaluations in county-level laboratories for implementing the assay are still required.展开更多
Objective To detect the specific mutations in rpoB gene of Mycobacterium tuberculosis by oligonucleotide microarray. Methods Four wild-type and 8 mutant probes were used to detect rifampin resistant strains. Target DN...Objective To detect the specific mutations in rpoB gene of Mycobacterium tuberculosis by oligonucleotide microarray. Methods Four wild-type and 8 mutant probes were used to detect rifampin resistant strains. Target DNA of M. tuberculosis was amplified by PCR, hybridized and scanned. Direct sequencing was performed to verify the results of oligonucleotide microarray Results Of the 102 rifampin-resistant strains 98 （96.1%） had mutations in the rpoB genes. Conclusion Oligonucleotide microarray with mutation-specific probes is a reliable and useful tool for the rapid and accurate diagnosis of rifampin resistance in M. tuberculosis isolates.展开更多
文摘Background The Xpert MTB/RIF showed high sensitivity and specificity in previous studies carried out in different epidemiological and geographical settings and patient populations in high-burden tuberculosis （TB） countries.However,there were little data obtained by validation or demonstration study of the assay in China.In this study,the performance of Xpert MTB/RIF was investigated in two county-level laboratories in Hunan Province,China.Methods Consecutive patients with suspected pulmonary tuberculosis （PTB） and suspicion for multidrug-resistant tuberculosis （MDR-TB） were enrolled.For each patient suspected to have PTB,three sputum specimens （one spot sputum,one night sputum,and one morning sputum） were collected and each sputum was tested with smear microscopy,L（o）wenstein-Jensen （LJ） culture,and Xpert MTB/RIF test.For comparison across subgroups and testing methods,95％ confidence intervals were calculated.All analyses were done with SPSS 16.0,and P ＜0.05 was regarded as significant.Results For case detection,the sensitivity of Xpert MTB/RIF was 100％ for smear-and culture-positive TB and 88.6％ for smear-negative and culture-positive TB; the overall sensitivity was 94.5％ for all culture-positive patients.The specificity was 99.8％.The sensitivity of Xpert MTB/RIF assay was 22.0％ in clinical TB patients and the specificity reached 100.0％ in the group of patients who are infected with nontuberculous mycobacteria.For the detection of rifampin resistance,the sensitivity of MTB/RIF RIF-resistance detection was 92.9％,and the specificity was 98.7％.Of the 26 Xpert MTB/RIF-positive and RIF-resistant patients confirmed by LJ proportion tests,20 （76.9％） patients were infected by MDR-TB.Conclusions The Xpert MTB/RIF assay is a highly sensitive and specific method for diagnosis of TB and RIF resistance,which will enable it to have the potential to be used in county-level laboratories and lead to the reduction of the infectious pool and improvements in TB control in China.Further evaluations in county-level laboratories for implementing the assay are still required.
基金supported by the grant from the National Natural Science Foundation of China (No. 30400018)
文摘Objective To detect the specific mutations in rpoB gene of Mycobacterium tuberculosis by oligonucleotide microarray. Methods Four wild-type and 8 mutant probes were used to detect rifampin resistant strains. Target DNA of M. tuberculosis was amplified by PCR, hybridized and scanned. Direct sequencing was performed to verify the results of oligonucleotide microarray Results Of the 102 rifampin-resistant strains 98 （96.1%） had mutations in the rpoB genes. Conclusion Oligonucleotide microarray with mutation-specific probes is a reliable and useful tool for the rapid and accurate diagnosis of rifampin resistance in M. tuberculosis isolates.
