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@#Abstract: Objective To analyze the accuracy and feasibility of GeneXpert MTB/RIF (GeneXpert) detection in the detection of Mycobacterium tuberculosis and the characteristics of rifampicin-resistant rpoB gene mutations. Methods A total of 4 234 sputum samples from suspected tuberculosis patients diagnosed in Sanya tuberculosis designated hospitals from 2015 to 2021 were selected and subjected to sputum smear, solid culture, drug sensitivity test by solid proportion method and GeneXpert detection. Results The positive detection rates of sputum smear, solid culture and GeneXpert of 4 234 sputum samples were 29.24% (1 238/4 234), 32.17% (1 362/4 234) and 35.40% (1 499/4 234), respectively. The positive detection rate of GeneXpert was higher than that of sputum smear, and the difference was statistically significant (χ2=36.775, P<0.01). It was slightly higher than solid culture, and the difference was not statistically significant (χ2=9.908, P=0.02). Taking solid culture results as the gold standard, the sensitivity and specificity of GeneXpert for detecting MTB were 91.04% (1 240/1 362) and 90.98% (2 613/2 872), respectively. According to the proportional drug susceptibility test results as the gold standard, the sensitivity and specificity of GeneXpert in detecting rifampicin resistance were 96.96% (96/99) and 98.86% (1 128/1 141), respectively, with the consensus rate of 98.71%. The accuracy of rifampicin resistance in GeneXpert group without probe mutation was significantly lower than that in group with probe mutation. There was a statistical difference in probe mutation frequency between newly treated and retreated cases. The analysis of rpoB gene mutation frequency characteristics showed: Probe E (50.00%) > Probe A (22.12%) > Probe D (14.42%) > Probe B (6.73%) > combined probe (5.77%) > Probe C (0.96%). Conclusions GeneXpert detection can quickly and effectively diagnose rifampicin-resistant tuberculosis, which is helpful for early clinical diagnosis and treatment. In this region, the rpoB gene mutation probes of rifampicin-resistant tuberculosis mainly occurr in Probe E and Probe A, with the least mutations in Probe C.
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@#Abstract: Objective To compare the diagnostic efficacy of the upgraded version of the GeneXpert automated fluorescent quantitative PCR system (GeneXpert MTB/RIF Ultra, GeneXpert Ultra) and the original version of the GeneXpert system (GeneXpert MTB/RIF, Xpert), real-time fluorescent quantitative nucleic acid detection (FQ-PCR), real-time fluorescent thermostatic amplification of Mycobacterium tuberculosis RNA (SAT-RNA), real-time fluorescent thermostatic amplification detection of DNA (thermostatic amplification method) and traditional BACTEC MGIT 960 liquid culture (culture method) for special specimens of tuberculosis, in order to analyze its application value in clinical detection. Methods Using prospective research methods, a total of 170 special specimens (including 47 pleural and ascites effusion samples, and 34 24-hour urinary sediment specimens, 49 tissue specimens and 40 fester specimens) were collected i'an Chest Hospital from January to September 2021. GeneXpert Ultra, Xpert, FQ-PCR, SAT-RNA, isothermal amplification, and traditional culture were used for detection. Clinical diagnosis was used as the standard, and sensitivity, specificity, positive predictive value, negative predictive value, coincidence rate, and Kappa value were compared among the methods. Results The sensitivities of GeneXpert Ultra, Xpert, FQ-PCR, SAT-RNA, isothermal amplification, and traditional culture were 65.18% (73/112), 49.11% (55/112), 37.50% (42/112), 19.64% (22/112), 8.04% (9/112), and 22.32% (25/112), respectively. The sensitivity of GeneXpert Ultra was higher than that of the other five methods, and the differences were statistically significant (χ2=66.25, 42.10, 28.89, 13.09, 4.92, 15.18, all P<0.05). GeneXpert Ultra result analysis showed that: 5.48%(4/73) cases had trace, that is, trace Mycobacterium tuberculosis load, 79.45% (58/73) cases were extremely low, 10.96% (8/73) cases were low, 2.74% (2/73) were medium, , and 1.36% (1/73) were high load. In 4 trace samples, the Xpert detection was negative for all. Of the 73 GeneXpert Ultra positive reports, 63 were rifampicin-sensitive, 6 were rifampicin-resistant, and 4 were rifampicin-resistant but of unclear resistance. Of the 55 Xpert positive reports, 45 were rifampicin-sensitive, 2 were rifampicin-resistant, and 8 were rifampicinresistant but of unclear resistance.. Conclusions The new generation of GeneXpert MTB/RIF Ultra has high sensitivity, specificity and drug resistance detection rate, and its advantage is even more apparent in the pathogenic diagnosis of special specimens of tuberculosis. It can be used as one of the preferred methods in samples with low bacterial load.
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@#Abstract: Objective To investigate the diagnostic efficacy of rifampin-resistant real-time fluorescent quantitative nucleic acid amplification detection technology (GeneXpert MTB/RIF) in bronchoalveolar lavage fluid (BALF) combined with peripheral blood tuberculosis infection T cell spot test (T-SPOT) and tuberculosis antibody (TB-Ab) in smear-negative pulmonary tuberculosis. Methods The clinical data of 114 cases of clinically diagnosed smear-negative pulmonary tuberculosis, 80 cases of non-tuberculous pulmonary diseases and 22 cases of smear-positive pulmonary tuberculosis in our hospital from January 2019 to January 2021 were retrospectively analyzed. The detection results of peripheral blood T-SPOT, TB-Ab and BALF GeneXpert in the three groups were analyzed. The sensitivity, specificity, negative predictive value, positive predictive value, false negative rate, false positive rate and Youden index of the three detection methods were compared. The differences in the positive detection rate of smear-negative pulmonary tuberculosis between the separate detection and the combined detection of the three methods were compared. The receiver operating characteristic curve (ROC) was performed to calculate the area under the curve (AUC). Results The sensitivity of BALF GeneXpert and peripheral blood T-SPOT and TB-Ab was 66.91%, 80.88% and 90.44%, respectively. The specificity was 98.75%, 73.75% and 41.25%, respectively; the diagnostic coincidence rates were 78.70%, 78.24% and 72.22%, respectively, which were higher than 70.00%. In the smear-negative pulmonary tuberculosis group, the positive detection rates of these three methods in the smear-negative pulmonary tuberculosis group were 63.15%, 79.82% and 90.35%, respectively, and the differences were statistically significant compared with those in the non-tuberculosis pulmonary disease group (all P<0.01). The positive detection rate of the three combined methods in the smear-negative pulmonary tuberculosis group was 96.49 %, which was significantly higher than that of TB-GeneXpert method and T-SPOT, and the differences were statistically significant (χ2=37.283, P<0.01; χ2=13.612, P<0.01); the Youden index of combined detection was significantly higher than that of single detection, and the AUC of combined detection was 0.977, which was significantly higher than that of single detection. Conclusion BALF GeneXpert combined with peripheral blood T-SPOT and TB-Ab can significantly improve the diagnostic rate of bacterial-negative pulmonary tuberculosis, providing a strong basis for guiding clinical treatment.
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Objective To evaluate GeneXpert MTB/RIF in diagnosis of pulmonary tuberculosis by comparing the lab results of diagnosed patients. Methods A total of 97 diagnosed pulmonary tuberculosis patients were enrolled from July 2017 to June 2018.Sputum smear microscopy (Ziehl-Neelsen stain), sputum culture (MGIT liquid culture) and Xpert MTB/RIF were conducted in all patients.Drug susceptibility test and strain identification by PNB were done for culture positive sputum samples.Consistency rate was calculated. Results In terms of M.tuberculosis detection, sensitivity and specificity of GeneXpert were 93.44% and 55.55%, respectively, compared with bacteriological examination (consistency rate 79.38%).Consistency rate of GeneXpert and PNB is 94.55%.In terms of RIF resistance test, sensitivity and specificity of GeneXpert were 66.67% and 98.08%, respectively, compared with phenotypic drug-susceptibility testing (consistency rate 96.36%). Conclusion GeneXpert MTB/RIF can be utilized in combination with smear microscopy and liquid culture to diagnose more etiologically positive patients, and can spot RIF resistance patients early.But strain identification and drug susceptibility test are still needed for individualized therapy and optimal treatment outcome.
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Objective To evaluate GeneXpert MTB/RIF in diagnosis of pulmonary tuberculosis by comparing the lab results of diagnosed patients. Methods A total of 97 diagnosed pulmonary tuberculosis patients were enrolled from July 2017 to June 2018.Sputum smear microscopy (Ziehl-Neelsen stain), sputum culture (MGIT liquid culture) and Xpert MTB/RIF were conducted in all patients.Drug susceptibility test and strain identification by PNB were done for culture positive sputum samples.Consistency rate was calculated. Results In terms of M.tuberculosis detection, sensitivity and specificity of GeneXpert were 93.44% and 55.55%, respectively, compared with bacteriological examination (consistency rate 79.38%).Consistency rate of GeneXpert and PNB is 94.55%.In terms of RIF resistance test, sensitivity and specificity of GeneXpert were 66.67% and 98.08%, respectively, compared with phenotypic drug-susceptibility testing (consistency rate 96.36%). Conclusion GeneXpert MTB/RIF can be utilized in combination with smear microscopy and liquid culture to diagnose more etiologically positive patients, and can spot RIF resistance patients early.But strain identification and drug susceptibility test are still needed for individualized therapy and optimal treatment outcome.
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Background: Delayed tuberculosis (TB) treatment increases the rate of spread of the bacilli in the community and mortality rates. Rapid diagnosis and early TB treatment initiation are crucial to successful outcomes and delays affect TB control programs. In Namibia, there is a paucity of data on the demographic factors affecting TB treatment initiation since GeneXpert MTB/RIF (Xpert) assay was introduced in 2017. Methods:This was a descriptive cross-sectional retrospective study conducted at Katutura Hospital TB clinic from 1stJuly 2018 to 31stMarch 2019. A total of seventy-two (72) participants comprising twenty-five (25) rifampicin resistant-TB (RR-TB) and forty-seven(47) non-RR-TB adult patients were enrolled using consecutive sampling. Patients’ medical records, Xpert results and a questionnaire were used to collect data. The data were analyzed using Stata statistical software version 12. Association between socio-demographic factors and treatment initiation delays were established using logistic regression analysis.Results:Staying with a TB patient (AOR=17.22, 95% CI: 2.29-129.773), employment status (AOR=1.23, 95% CI, 002-129), previous TB treatment (AOR=2.19, 95% CI: 0.076-0.86) and being HIV positive (AOR= 1.23, 95% CI: 0.0034-057) were thesocio-demographic factorsthat weresignificantly associated with treatment initiation delays.Treatment initiation delay median time at Katutura Intermediate Hospital TB Clinic was 10 days (IQR: 1-32) and 3 days (IQR: 0-12) for RR-TB and non-RR-TB respectively.Conclusion: The prolonged treatment initiation delays among HIV positive RR-TB patients might be due to low adherence to HIV care interventions. Staying with a household TB patient and those who were previously treated for TB were also associated with treatment initiation delays. Poor health systems infrastructure and stigma could be the determinants of this delay in these groups. An integrated family-based approach to TB and HIV care involving health care workers can mitigate TB treatment delays post-diagnosis. Further studies should explore the factors associated with late initiation to second-line treatment from a community perspective. Lastly, there is a need to assess the cost-utility of bedaquiline and delamanid drugs roll-out in Namibian health care in comparisonwith the standard treatment.
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Tuberculosis is a major public health problem worldwide and remains one of the most significant causes of death from an infectious agent. India contributes to 25.5% of the global new TB case detection. In recent times, emphasis has shifted from older phenotypically and biochemical methods of diagnosis to molecular methods such as GeneXpert MTB/RIF, a real time PCR that can detect MTB and rifampicin resistence simultaneously. Methods: This study aims at assessing the performance of acid fast bacilli (AFB) smear microscopy in comparison with GeneXpert MTB RIF, in the diagnosis of pulmonary tuberculosis. Study was a cross-sectional study carried out at the Department of Pulmonary Medicine, Muzaffarnagar Medical College, from January 2018 to April 2019. Result: The detection of MTB and rifampicin resistance using the Xpert MTB/RIF assay was assessed in 67 specimens from patients suspected of having pulmonary tuberculosis and compared with conventional smear microscopy. Out of these 67 sputum specimens, 38 samples were MTB positive by smear microscopy while 56 samples were MTB detected by Gene Xpert assay. Gene Xpert detected 18 additional tubercular cases and identify two cases of Rifampicin resistant MTB. Conclusion: Study show that there was no statistically significance in diagnostic value between GeneXpert and AFB smear microscopy in sputum samples however Gene Xpert MTB/RIF is useful method for rapid detection of MTB and Rifampicin resistance simultaneously.
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Objective To explore the application values of GeneXpert MTB/RIF assay (Xpert assay) for rifampicin resistance and multidrug resistant tuberculosis (MDR-TB).Discordance of Xpert and L-J proportion DST of rifampicin was analyzed.Methods Specimens of 1 300patients from January 2014to June 2016in our hospital were collected for solid culture, Xpert assay and L-J proportion drug susceptibility test (DST).Rifampicin resistance detected by Xpert assay was compared with L-J proportion method as a gold standard.Sequencing of rpoB gene and determination of minimum inhibition concentration were accomplished on the discordant MTB strains between Xpert and L-J proportion DST.Results Compared with the DST, the sensitivity, specificity, positive and negative predictive value of Xpert assay for rifampicin resistance were 99.31％, 97.82％, 92.88％and 99.80％, respectively.Among 1 300culture-positive specimens, mutations were detected from 309specimens by Xpert assay, which included 125initial treatment and 184retreatment patients.Among309specimens with rpoB gene mutations, mutations detected by probes E, D and B were common, and the rates were 65.70％, 14.56％and 10.68％, respectively.Totally 239patients were MDR-TB[77.35％ (239/309) ], of which 94initial treatment patients[75.20％ (94/125) ]and 145retreatment patients[78.80％ (145/184) ]were MDR-TB.Among 22strains which were detected rpoB gene mutations by Xpert, but sensitive by L-J proportion DST, 6strains had no mutation in rpoB gene rifampicin resistance determining region (RRDR);16strains had mutations, which were mainly located in L511Pcodon (8strains) and L533Pcodon (4strains).Among 2strains which had no rpoB gene mutation by Xpert, but were resistant by L-J proportion DST, 1strain had no mutation in rpoB gene RRDR region;1strain had mutation which was located in E546G codon outside RRDR region.Conclusion Xpert assay can be used to rapidly detect rifampicin resistance and to screen MDR-TB.Mutations in codon 511and 533are related to low-level resistance to rifampicin.
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Objective@#To evaluate the performence of GeneXpert MTB/RIF and BACTEC-MGIT 960 on detecting Mycobacterium tuberculosis and rifampicin resistance for pneumoconiosis-associated tuberculosis patients.@*Methods@#The recruited 133 suspected active pneumoconiosis-associated tuberculosis hospitalized cases, morning sputum samples were collected to do modified L-J culture, conventional proportion method drug susceptibility test, GeneXpert MTB/RIF and BACTEC-MGIT 960. Analyze the sensitivity and specificity of the 133 sputum from patients, the positive rates of patients with tuberculosis in GeneXpert MTB/RIF test, BACTEC-MGIT 960 and modified L-J culture were 37.59%, 34.59% and 30.08% respectively. There was no significant difference among the three tests respectively (P>0.05) . According to the modified L-J culture, the sensitivity of GeneXpert MTB/RIF and BACTEC-MGIT 960 in detecting tuberculosis were 92.5% and 95.0% respectively, and specificity in rifampicin resistance were 86.0% and 91.4% respectively. There was no significant difference between GeneXpert MTB/RIF and BACTEC-MGIT 960 (P>0.05) . According to conventional proportion method drug susceptibility test, the sensitivity of GeneXpert MTB/RIF and BACTEC-MGIT 960 in detecting rifampicin resistance were 90.0% and 100%, and specificity were 92.6% and 96.4%. There was no significant difference between GeneXpert MTB/RIF and BACTEC-MGIT 960 (P>0.05) .@*Conclusion@#The GeneXpert MTB/RIF has good performence of detecting tuberculosis and rifampicin resistance. It has good application value among pneumoconiosis-associated tuberculosis patients.
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BACKGROUND: GeneXpert MTB/RIF is a real-time PCR assay with established diagnostic performance in pulmonary and extra-pulmonary forms of tuberculosis. The aim of this study was to assess the contribution of GeneXpert MTB/RIF assay to the management of patients with any form of active tuberculosis in a single large tertiary center in Saudi Arabia, with a special focus on the impact on time to start of antituberculous therapy compared with Ziehl-Neelsen (ZN) smears and mycobacterial cultures. MATERIALS AND METHODS: Clinical, radiological and laboratory records for all patients who were commenced on antituberculous therapy between March 2011 and February 2013 were retrospectively reviewed. RESULTS: A total of 140 patients were included, 38.6% of which had pulmonary tuberculosis. GeneXpert MTB/RIF was requested for only 39.2% of patients and was the only reason for starting antituberculous therapy for only 12.1%. The median time to a positive GeneXpert MTB/RIF result was 0 days (IQR 3) compared with 0 day (IQR 1) for smear microscopy (P > 0.999) and 22 days (IQR 21) for mycobacterial cultures (P < 0.001). No patients discontinued antituberculous therapy because of a negative GeneXpert MTB/RIF result. CONCLUSIONS: In a setting wherein physicians are highly experienced in the diagnosis and treatment of tuberculosis, GeneXpert MTB/RIF was remarkably under-utilized and had only a limited impact on decisions related to starting or stopping antituberculous therapy. Cost-effectiveness and clinical utility of routine testing of all smear-negative clinical samples submitted for tuberculosis investigations by GeneXpert MTB/RIF warrant further study.
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Humans , Diagnosis , Life Change Events , Microscopy , Real-Time Polymerase Chain Reaction , Retrospective Studies , Saudi Arabia , Tuberculosis , Tuberculosis, PulmonaryABSTRACT
O diagnóstico laboratorial da tuberculose é de fundamental importância para o correto tratamento e controle da disseminação da doença. Dentre os principais métodos diagnósticos, os testes baseados em biologia molecular vêm ocupando cada vez mais um papel de destaque; entretanto, ainda não substituem por completo os métodos tradicionais, como a cultura e a pesquisa direta. A dosagem da adenosina deaminase (ADA) tem utilidade no diagnóstico de doença extrapulmonar e o teste de liberação de interferon gama linfocitário (IGRA) é de utilidade no diagnóstico de tuberculose latente. A utilização conjunta dos diferentes métodos disponíveis tem trazido grandes vantagens clínicas
The laboratory diagnosis of tuberculosis is of fundamental importance for the correct treatment and control the spread of the disease. Among the main diagnostic methods, the tests based on molecular biology are occupying an increasingly prominent role, however, has not yet completely replace traditional methods such as culture and direct search. The determination of adenosine deaminase (ADA) has useful in diagnosis of extrapulmonary disease and the interferon gamma release assay (IGRA) is useful in the diagnosis of latent tuberculosis. The combination use of different methods available has brought great clinical advantages