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Objective:To evaluate the diagnostic effects of Xpert MTB/RIF, Fluorescence PCR melting curve and gene chip technology for rapid screening of rifampicin-resistant tuberculosis.Methods:The clinical data of 150 patients diagnosed with tuberculosis by Bactec MGIT 960 liquid culture drug susceptibility in Zhejiang Chinese Medicine and Western Medicine Integrated Hospital from September 2016 to August 2019 were collected, including Xpert MTB/RIF and gene chip results. The isolated and cultured strains from patients were subjected to fluorescence PCR melting curve detection. Using Bactec MGIT 960 drug susceptibility results as the reference, the diagnostic efficacy of Xpert MTB/RIF, Fluorescence PCR melting curve and gene chip technology for rifampicin resistance were analyzed, and the receiver operating characteristic curve (ROC) was drawn for comparative analysis.Results:Take Bactec MGIT 960 as the gold standard, the sensitivity of Xpert MTB/RIF, Fluorescence PCR melting curve and gene chip technology for rifampicin resistance were 88.89% (16/18), 94.44% (17/18), 88.89% (16/18) respectively; the specificity were 96.21% (127/132), 96.21% (127/132), 95.45% (126/132), respectively. There was no statistically significant difference in the sensitivity and specificity among the three detection methods ( P>0.05). The Kappa values of the three molecular methods for detecting rifampicin resistance were 0.794, 0.827 and 0.770, respectively. The three detection methods have good diagnostic value for rifampicin resistance ( P<0.01), but there is no statistically significant difference between the three methods ( P>0.05). There were 8 cases of inconsistent results between the three methods and Bactec MGIT 960 drug sensitivity. Conclusion:Xpert MTB/RIF, Fluorescence PCR melting curve and gene chip technology have comparable ability to detect rifampicin resistance, all of these have high sensitivity and specificity for detecting rifampicin resistance and are suitable for rapid screening.
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Objective To compare the application of PCR-fluorescence probe, Bactec MGIT960 and Xpert MTB／RIF in diagnosis of tuberculosis from non-respiratory specimens.Methods Non-respiratory specimens from 225 patients with suspected tuberculosis admitted in Zhejiang Hospital of Integrated Chinese Medicine and Western Medicine from October 2017 to August 2018 were collected.There were 177 cases of tuberculosis and 48 cases of non-tuberculosis confirmed by clinical diagnosis.All specimens were tested with PCR-fluorescence probe, Xpert MTB／RIF and Bactec MGIT960.The clinical diagnostic results were used as the gold standard, and the receiver operating characteristic curve ( ROC) was drawn to evaluate the diagnostic values of three methods.The consistency of PCR-fluorescence probe method with Xpert MTB／RIF assay was analyzed.Results The sensitivity of PCR-fluorescent probe, Xpert MTB／RIF and Bactec MGIT960 in diagnosis of tuberculosis was 53.67%(95／177), 58.76%(104／177) and 31.07%(55／177), respectively.The sensitivity of PCR-fluorescent probe and Xpert MTB／RIF was higher than that of Bactec MGIT 960 culture ( χ2 ＝17.60 and 27.41, P＜0.01), while there was no significant difference between the PCR-fluorescent probe and the Xpert MTB／RIF (χ2 ＝0.93, P＞0.05).The specificity of three methods were 100.00%(48／48), 100.00%(48／48) and 97.92%(47／48), respectively (F＝1.83, P＞0.05).ROC curve analysis showed that the area under the ROC curve ( AUC) of PCR-fluorescent probe, Xpert MTB／RIF, and Bactec MGIT960 was 0.768, 0.794, and 0.645, respectively.The diagnostic value of PCR-fluorescent probe and Xpert MTB／RIF for tuberculosis was significantly higher than that of Bactec MGIT960 (Z＝5.19 and 6.52, P＜0.01); while Xpert MTB／RIF was superior to PCR-fluorescence probe (Z＝2.8, P＜0.05).In various types of specimens , there was no significant difference in the detection rate of tuberculosis between PCR-fluorescent probe method and Xpert MTB／RIF (χ2 ＝0.73, P＞0.05).The PCR-fluorescent probe and Xpert MTB／RIF had a good consistency (kappa＝0.829).Conclusion Xpert MTB／RIF is superior to PCR-fluorescence probe in the detection of tuberculosis in non-respiratory specimens such as tissues and pus, but the two have good consistency.The PCR-fluorescence probe method is economical and practical , and easy to promote, which has a high clinical application prospects.
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To evaluate the diagnostic value of heterologous serum antibody for tuberculosis ,we detected the serum spec-imens from 102 patients with tuberculosis (included 73 pulmonary TB and 29 extrapulmonary TB) ,223 patients with other re-spiratory diseases and 100 healthy people were enrolled into the study .Results of clinical diagnosis as the golden standard were used to evaluate sensitivity and specificity of the tuberculosis antibody .Tuberculosis antibody (IgG/IgM ) ,sputum bacterial culture and sputum smear were used to test M .tuberculosis infection parallelly .Results were compared by chi-square test .Re-sults showed that the sensitivity and specificity of IgG/IgM tuberculosis antibodies in diagnosis of tuberculosis were respectively 74 .51% and 91 .64% .The sensitivity of IgG/IgM tuberculosis antibodies in diagnosis of pulmonary and extrapulmonary tuber-culosis were respectively 82 .19% and 55 .17% ,which were significant differences between the positive detection rate of pulmo-nary tuberculosis and extrapulmonary tuberculosis (P>0 .05) .The positive rate of IgG/IgM tuberculosis antibodies was higher than those in sputum culture and sputum smear (P＜0 .05) .A total of 102 cases of tuberculosis in patients in different age groups were analyzed ,and the positive detection rate of children and elderly group were 58 .33% and 36% ,respectively ,which were far below the rate in the youth group (96 .15% ) and the middle-aged group (89 .74% ) .The chi-square value for the differences in age group in the sensitivity of IgG/IgM tuberculosis antibodies was significant difference (P＜0 .05) .Six out of 425 cases of specimens were found as M .intracellulare ,and 2 as M .abscessus .However ,the IgG/IgM tuberculosis antibodies were negative in diagnosis of non-tuberculous mycobacteria .Antibody (IgG/IgM ) is sensitive ,rapid ,convenient ,and easy to manipulate the screening of tuberculosis .