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Objectives: Post-treatment recurrence remains a challenge for the global control of tuberculosis (TB). This study investigated longitudinal data on pulmonary TB recurrence rates and risk factors for recurrence among successfully treated smear-positive tuberculosis cases in China., Methods: Between 1st January 2009 and 31st December 2016 we evaluated 33 441 treatment-naïve patients diagnosed with sputum-smear-positive, non-multidrug-resistant TB in Hangzhou, China. We included the data of 9828 patients with TB who were treated successfully., Results: A total of 4.9% of the cases were recurrent (479/9828), identified within a median observation period lasting 1565 days. Altogether, 51.1% (245/479) of the recurrences occurred within 1 year. The cumulative 2- and 5-year recurrence rates were 3.90% (95% confidence interval (CI) 3.3-4.5%) and 5.4% (95%CI 4.8-6.0%), respectively. Prolonged treatment (over 7 months) occurred in 64.7% (6363/9828), with a median treatment duration of 242 days (interquartile range 195-348 days). Male sex (adjusted hazard ratio (aHR) (95%CI) 1.61 (1.30-2.00), p < 0.001), age 60 years old or older (aHR (95%CI) 2.03 (1.70-2.44), p < 0.001), pulmonary cavity (aHR (95%CI) 1.51 (1.25-1.82), p < 0.001) and sputum positivity at 2 months (aHR (95%CI) 1.39 (1.05-1.81), p 0.02) all increased the risk of TB recurrence. Prolonged treatment was associated with reduced TB recurrence (aHR (95%CI) 0.73 (0.61-0.88), p 0.001)., Conclusions: Recurrence remains a problem for successfully treated patients with sputum-smear-positive pulmonary TB, especially those with independent risk factors. Further analysis of prolonged treatment is required., (Copyright © 2021. Published by Elsevier Ltd.)

Objectives: Delay in diagnosis of tuberculosis (TB) is an important but under-appreciated problem. Our study aimed to analyse the patient pathway and possible risk factors of long diagnostic delay (LDD)., Methods: We enrolled 400 new bacteriologically diagnosed patients with pulmonary TB from 20 hospitals across China. LDD was defined as an interval between the initial care visit and the confirmation of diagnosis exceeding 14 days. Its potential risk factors were investigated by multivariate logistic regression and multilevel logistic regression. Hospitals in China were classified by increasing size, from level 0 to level 3. TB laboratory equipment in hospitals was also evaluated., Results: The median diagnostic delay was 20 days (IQR: 7-72 days), and 229 of 400 patients (57.3%, 95%CI 52.4-62.1) had LDD; 15% of participants were diagnosed at the initial care visit. Compared to level 0 facilities, choosing level 2 (OR 0.27, 95%CI 0.12-0.62, p 0.002) and level 3 facilities (OR 0.34, 95%CI 0.14-0.84, p 0.019) for the initial care visit was independently associated with shorter LDD. Equipping with smear, culture, and Xpert at initial care visit simultaneously also helped to avoid LDD (OR 0.28, 95%CI 0.09-0.82, p 0.020). The multilevel logistic regression yielded similar results. Availability of smear, culture, and Xpert was lower in level 0-1 facilities than in level 2-3 facilities (p < 0.001, respectively)., Conclusions: Most patients failed to be diagnosed at the initial care visit. Patients who went to low-level facilities initially had a higher risk of LDD. Improvement of TB laboratory equipment, especially at low-level facilities, is urgently needed., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Tuberculosis (TB) is now the leading cause of death from infectious disease. Rapid screening and diagnostic methods for TB are urgently required. Rapid development of metagenomics next-generation sequencing (mNGS) in recent years showed promising and satisfying application of mNGS in several kinds of infectious diseases. However, research directly evaluating the ability of mNGS in TB infection is still scarce. Methods: We conducted an adult prospective study in mainland China to evaluate the diagnostic performance of mNGS for detection of Mycobacterium tuberculosis complex (MTB) in multiple forms of direct clinical samples compared with GeneXpert MTB/RIF assay (Xpert), traditional diagnostic methods, and the clinical final diagnosis. Results: Of 123 patients presenting with suspected active TB infection between June 1, 2017, and May 21, 2018, 105 patients underwent synchronous tuberculous testing with culture, Xpert, and mNGS on direct clinical samples including sputum, cerebrospinal fluids, pus, etc. During follow-up, 45 of 105 participants had clinical final diagnosis of active TB infection, including 13 pulmonary TB cases and 32 extrapulmonary TB cases. Compared to clinical final diagnosis, mNGS produced a sensitivity of 44% for all active TB cases, which was similar to Xpert (42%) but much higher than conventional methods (29%). With only one false-positive result, mNGS had a specificity of 98% in our study. mNGS yielded significantly much higher sensitivity in pre-treatment samples (76%) than post-treatment ones (31%) ( P = 0.005), which was also true for Xpert and conventional methods. Combining Xpert and mNGS together, the study identified 27 of 45 active TB cases (60%), including all 13 conventional method-identified cases, and the result reached statistical significance compared to conventional methods (McNemar-test P < 0.001). Conclusions: mNGS had a similar diagnostic ability of MTB compared with Xpert and showed potential for a variety of clinical samples. Combined mNGS and Xpert showed an overall superior advantage over conventional methods and significantly improved the etiology diagnosis of both MTB and other pathogens. The result that anti-TB treatment significantly reduced diagnostic efficacy of culture, Xpert, and mNGS highlighted the importance of collecting samples before empirical treatment., (Copyright © 2019 Zhou, Wu, Ruan, Jiang, Chen, Shen, Zhu, Ying, Qian, Wang, Ai and Zhang.)

Rapid and simple-to-use diagnostic methods for tuberculosis are urgently needed. Recent development has unveiled the diagnostic power of the CRISPR system in the detection of viral infections. However, its potential use in detecting the Mycobacterium tuberculosis complex (MTB) remained unexplored. We developed a rapid CRISPR-based assay for TB detection and conducted a retrospective cohort study of 179 patients to evaluate the CRISPR-MTB test for identifying MTB in various forms of direct clinical samples. Its diagnostic performance was compared, in parallel with culture and the GeneXpert MTB/RIF assay (Xpert). The CRISPR-MTB test is highly sensitive with a near single-copy sensitivity, demands less sample input and offers shorter turnaround time than Xpert. When evaluated in the clinical cohort of both pulmonary and extra-pulmonary tuberculosis, the CRISPR-MTB test exhibited an overall improved sensitivity over both culture (79% vs 33%) and Xpert (79% vs 66%), without comprise in specificity (62/63, 98%). The CRISPR-MTB test exhibits an improved overall diagnostic performance over culture and Xpert across a variety of sample types, and offers great potential as a new diagnostic technique for both pulmonary and extra-pulmonary tuberculosis.

Objective: To determine whether there is a major difference in protein levels between isoniazid-resistant and susceptible M. tuberculosis strains., Methods: The proteins extracted from 9 isoniazid-resistant M. tuberculosis strains and 7 isoniazid-susceptible M. tuberculosis strains were analyzed by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Protein spots remarkly increased in isoniazid-resistant M. tuberculosis strains were digested in gel by enzyme and the mass of generated peptides were measured by matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS). The data obtained from peptide mass fingerprinting were used in protein database search. These genes of all strains were sequenced., Result: In all protein spot differences, 5 protein spots were upregulated in isoniazid-resistant strains and identified as Rv1446c, Rv3028c, Rv0491, Rv2971, and Rv2145 by (MALDI-TOF-MS)., Conclusion: These results suggest that the differentially expressed proteins from isoniazid-resistant strains might be used as potential immuno-diagnostic antigens and candidate novel drug targets against drug resistant tuberculosis.

Objective: To set up and evaluate the method of phage amplified biologically assay (PhaB) in rapid detection of pyrazinamide (PZA) resistance., Methods: The PhaB assay was developed and applied in detecting PZA resistance in 108 clinical isolates of Mycobacterium tuberculosis and the results were compared with those of the absolute concentration method. The minimum inhibitory concentration (MIC) was detected for all discrepancy isolates., Results: The results showed that the optimal detecting condition was pH 5.5, PZA 200 microg/ml and 48 h. Of the 108 strains of Mycobacterium tuberculosis, 28 strains were PZA-susceptible and 80 strains were PZA-resistant detected by PhaB; while 32 strains were PZA-susceptible and 76 strains were PZA-resistant by absolute concentration method. Twenty-eight of the 108 strains were PZA-susceptible and 71 were PZA-resistant by the two methods. The concordant isolates of determination of PZA resistance were 99 by the two methods and the concordance rates was 91.7%. There were 9 strains in discordant isolates, of which 7 were the same with MIC method and gene chip in drug susceptibility. If the results of absolute concentration method was the gold standard, the sensitivity, specificity, positive and negative predictive values, as well as accuracy of PhaB assay was 94.7%, 84.8%, 93.4%, 87.5% and 91.7% respectively., Conclusion: The PhaB assay can be used as a rapid screening method for detection of drug susceptibility of PZA in clinical isolates of Mycobacterium tuberculosis.

Objective: To develop a new multiplex allele-specific polymerase chain reaction (MAS-PCR) assay to detect the main mutations in the rifampin resistance dependent region, which has been reported to account for the majority of clinic Mycobacterium tuberculosis resistant to rifampin., Methods: Based on the sequence of rpoB gene, three specific primers were designed for the MAS-PCR to detect the most common mutations in codons 531, 526, 516 of rpoB gene., Results: The purified DNA preparations of 91 clinical strains of Mycobacterium tuberculosis were used to optimize the PCR. The mutations in codon 531, 526, 516 were detected by the MAS-PCR. Compared with the results of direct sequencing of rpoB gene, no mutation was detected in the sensitive strains. For rifampin-resistant strains, the total sensitivity was 81.5% (66/81)., Conclusions: MAS-PCR is a new molecular method with a high sensitivity and specificity, which can be used to detect the 3 main mutations of rpoB gene rapidly and economically. It can be used in clinical laboratories to detect the rifampin-resistant strains of Mycobacterium tuberculosis.

Objective: To study the relationship between KatG 315 mutation and isoniazid (INH) resistance in M. tuberculosis by template-directed dye-terminator incorporation with fluorescence polarization detection (TDI-FP), and to develop a new method that can detect INH-resistant M. tuberculosis precisely and quickly., Methods: Isolates of M. tuberculosis resistant to INH from 82 tuberculosis patients were cultured on culture medium with different INH concentrations. DNA of all M. tuberculosis samples was extracted and amplification of 271 bp KatG gene fragment was carried out by polymerase chain reaction (PCR). After digestion of the excess primers and dNTPs in PCR products by clean-up reagents, template-directed dye-terminator incorporation reaction was performed, and the Acyclo-terminators labeled Rhodamine 110 (R110) or 6-carboxytetramethylrhodamine (TAMRA) were incorporated into the detection primers specifically. Then fluorescence polarization value was measured using Victor2 multi-label counter and the genotypes of the mutation site in 315 condon of KatG gene of all samples were investigated., Results: There were 15 out of the 29 isolates of M. tuberculosis with high INH-resistance showed G-->C mutation in 315 condon of KatG gene, including 4 isolates with both mutated and non-mutated trains, the mutation frequency being 52%. In 32 isolates of M. tuberculosis with low INH-resistance, 15 were mixed infection, the mutation frequency being 47%. No mutation in 315 condon of KatG gene was found in 21 susceptible isolates of M. tuberculosis., Conclusions: The G-->C mutation in 315 condon of KatG gene was associated with INH-resistance of M. tuberculosis. TDI-FP technology was a reliable, easy to use and high-through method to detect mutation of KatG gene. It may be a useful technique for the diagnosis of INH-resistance in the future.