Development of a novel detection technology for drug resistance mutation sites of Mycobacterium tuberculosis using Luminex liquid chip technology

Purpose: To develop a novel detection technology for drug-resistance mutation sites of Mycobacterium tuberculosis (MTB) using a Luminex liquid chip.Methods: Using polymerase chain reaction (PCR) amplification and hybridization analysis, MTB infection and drug-resistant mutation sites of the first-line and second-line anti-MTB drugs were simultaneously identified. A novel detection method was applied to analyze the wild-type standard strains of MTB and 33 clinical samples, and the results were compared with Sanger sequencing results for PCR products.Results: It was revealed that the sensitivity (100 %) and specificity (100 %) of the novel detection method for 31 samples were satisfactory, and all mutation sites were correctly detected. Compared with traditional PCR and culture-based drug sensitivity test, the novel detection method increased the speed of identification of drug-resistant TB, reduced clinicians' workload, and decreased treatment cost. Among 31 samples, 12.90 % were resistant to isoniazid (4/31), 35.48 % to rifampicin (11/31), and 12.90 % to ofloxacin (p < 0.05). Furthermore, 2 (6.45 %) samples were resistant to both isoniazid and rifampicin, 2 (6.45 %) samples to both rifampicin and ofloxacin, and 1 (3.22 %) sample to both isoniazid and ofloxacin, and 1 (3.22%) sample to all the three drugs (p < 0.05).Conclusion: Development and wide application of this novel detection method will facilitate the treatment of MTB, thus reducing the spread of drug-resistant MTB, and improving the prevention and treatment of MTB

Antibacterial activity of the novel oxazolidinone contezolid (MRX-I) against Mycobacterium abscessus

ObjectiveTo evaluate contezolid (MRX-I) antibacterial activity against Mycobacterium abscessus in vitro and in vivo and to assess whether MRX-I treatment can prolong survival of infected zebrafish.MethodsMRX-I inhibitory activity against M. abscessus in vitro was assessed by injecting MRX-I into zebrafish infected with green fluorescent protein-labelled M. abscessus. Thereafter, infected zebrafish were treated with azithromycin (AZM), linezolid (LZD) or MRX-I then maximum tolerated concentrations (MTCs) of drugs were determined based on M. abscessus growth inhibition using one-way ANOVA. Linear trend analysis of CFU counts and fluorescence intensities (mean ± SE values) was performed to detect linear relationships between MRX-I, AZM and LZD concentrations and these parameters.ResultsMRX-I anti-M. abscessus minimum inhibitory concentration (MIC) and MTC were 16 μg/mL and 15.6 μg/mL, respectively. MRX-I MTC-treated zebrafish fluorescence intensities were significantly lower than respective LZD group intensities (whole-body: 439040 ± 3647 vs. 509184 ± 23064, p < 0.01); head: 74147 ± 2175 vs. 95996 ± 8054, p < 0.05). As MRX-I concentration was increased from 0.488 μg/mL to 15.6 μg/mL, zebrafish whole-body, head and heart fluorescence intensities decreased. Statistically insignificant differences between the MRX-I MTC group survival rate (78.33%) vs. corresponding rates of the 62.5 μg/mL-treated AZM MTC group (88.33%, p > 0.05) and the 15.6 μg/mL-treated LZD MTC group (76.67%, p > 0.05) were observed.ConclusionMRX-I effectively inhibited M. abscessus growth and prolonged zebrafish survival when administered to M. abscessus-infected zebrafish, thus demonstrating that MRX-I holds promise as a clinical treatment for human M. abscessus infections

Antibacterial activity of the novel compound Sudapyridine (WX-081) against Mycobacterium abscessus

ObjectiveThis study aimed to investigate sudapyridine (WX-081) antibacterial activity against Mycobacterium abscessus in vitro and its effect on in vivo bacterial growth and host survival using a zebrafish model of M. abscessus infection.MethodsWX-081 in vitro antibacterial activity was assessed based on growth inhibition of M. abscessus standard strain ATCC19977 and 36 clinical isolates. Maximum tolerated concentrations (MTCs) of WX-081, bedaquiline, and azithromycin and inhibition of M. abscessus growth were assessed in vivo after fluorescently labelled bacilli and drugs were injected into zebrafish. Bacterial counts were analysed using one-way ANOVA and fluorescence intensities of zebrafish tissues were analysed and expressed as the mean ± SE. Moreover, Kaplan-Meier survival analysis was conducted to assess intergroup differences in survival of M. abscessus-infected zebrafish treated with different drug concentrations using a log-rank test, with a p value <0.05 indicating a difference was statistically significant.ResultsDrug sensitivity testing of M. abscessus standard strain ATCC19977 and 36 clinical isolates revealed MICs ranging from 0.12-0.96 µg/mL and MIC50 and MIC90 values of 0.48 µg/mL and 0.96 µg/mL, respectively. Fluorescence intensities of M. abscessus-infected zebrafish tissues was lower after treatment with the WX-081 MTC (62.5 µg/mL) than after treatment with the azithromycin MTC (62.5 µg/mL) and the bedaquiline MTC (15.6 µg/mL). When the concentration of WX-081 increased from 1.95µg/mL to 1/8 MTC(7.81µg/mL), the survival rate of zebrafish at 4-9 dpf decreased from 90.00% to 81.67%.ConclusionWX-081 effectively inhibited M. abscessus growth in vitro and in vivo and prolonged survival of M. abscessus-infected zebrafish, thus indicating that WX-081 holds promise as a clinical treatment for M. abscessus infection

A study of risk factors for tuberculous meningitis among patients with tuberculosis in China: An analysis of data between 2012 and 2019

PurposeThe present study aimed to explore the risk factors for tuberculous meningitis (TBM) among patients with tuberculosis (TB).MethodsThis retrospective study was conducted on patients with TB who were hospitalized in Beijing Chest Hospital between January 2012 and December 2019. Demographic and clinical data of patients with TB were extracted from electronic medical records using a standardized data collection system. Logistic regression was used to analyze the risk factors associated with TBM.ResultsOf the total number of 22,988 cases enrolled, 3.1% were cases of TBM, which included 127 definite and 581 probable TBM, respectively. Multivariate analysis showed that definite TBM was significantly associated with patients aged < 30 years [adjusted odds ratio (aOR) = 3.015, 95% confidence interval (CI): (1.451–6.266)], who were farmers [aOR = 1.490, 95%CI: (1.020–2.177)], with miliary pulmonary TB [aOR = 105.842, 95%CI: (71.704–156.235)], and with malnutrition [aOR = 2.466, 95%CI: (1.110–5.479)]. Additionally, probable TBM was significantly associated with patients aged < 30 years [aOR = 2.174, 95% CI: (1.450–3.261)], aged 30–59 years [aOR = 1.670, 95% CI: (1.222–2.282)], who were farmers [aOR = 1.482, 95%CI: (1.203–1.825)], with miliary pulmonary TB [aOR = 108.696, 95%CI: (87.122–135.613)], and with a digestive system TB [aOR = 2.906, 95%CI: (1.762–4.793)].ConclusionAn age of < 30 years, being a farmer, and having miliary pulmonary TB were risk factors for TBM among patients with TB. Further screening of patients with TB with aforementioned characteristics could facilitate clinicians to identify patients with TBM at an early stage

Evaluation of the Ribosomal Protein S1 Gene (rpsA) as a Novel Biomarker for Mycobacterium Species Identification

Objectives. To evaluate the resolution and reliability of the rpsA gene, encoding ribosomal protein S1, as a novel biomarker for mycobacteria species identification. Methods. A segment of the rpsA gene (565 bp) was amplified by PCR from 42 mycobacterial reference strains, 172 nontuberculosis mycobacteria clinical isolates, and 16 M. tuberculosis complex clinical isolates. The PCR products were sequenced and aligned by using the multiple alignment algorithm in the MegAlign package (DNASTAR) and the MEGA program. A phylogenetic tree was constructed by the neighbor-joining method. Results. Comparative sequence analysis of the rpsA gene provided the basis for species differentiation within the genus Mycobacterium. Slow-and rapid-growing groups of mycobacteria were clearly separated, and each mycobacterial species was differentiated as a distinct entity in the phylogenetic tree. The sequences discrepancy was obvious between M. kansasii and M. gastri, M. chelonae and M. abscessus, M. avium and M. intracellulare, and M. szulgai and M. malmoense, which cannot be achieved by 16S ribosomal DNA (rDNA) homologue genes comparison. 183 of the 188 (97.3%) clinical isolates, consisting of 8 mycobacterial species, were identified correctly by rpsA gene blast. Conclusions. Our study indicates that rpsA sequencing can be used effectively for mycobacteria species identification as a supplement to 16S rDNA sequence analysis

Evaluation of the Ribosomal Protein S1 Gene (rpsA) as a Novel Biomarker for Mycobacterium Species Identification

Objectives. To evaluate the resolution and reliability of the rpsA gene, encoding ribosomal protein S1, as a novel biomarker for mycobacteria species identification. Methods. A segment of the rpsA gene (565 bp) was amplified by PCR from 42 mycobacterial reference strains, 172 nontuberculosis mycobacteria clinical isolates, and 16 M. tuberculosis complex clinical isolates. The PCR products were sequenced and aligned by using the multiple alignment algorithm in the MegAlign package (DNASTAR) and the MEGA program. A phylogenetic tree was constructed by the neighbor-joining method. Results. Comparative sequence analysis of the rpsA gene provided the basis for species differentiation within the genus Mycobacterium. Slow- and rapid-growing groups of mycobacteria were clearly separated, and each mycobacterial species was differentiated as a distinct entity in the phylogenetic tree. The sequences discrepancy was obvious between M. kansasii and M. gastri, M. chelonae and M. abscessus, M. avium and M. intracellulare, and M. szulgai and M. malmoense, which cannot be achieved by 16S ribosomal DNA (rDNA) homologue genes comparison. 183 of the 188 (97.3%) clinical isolates, consisting of 8 mycobacterial species, were identified correctly by rpsA gene blast. Conclusions. Our study indicates that rpsA sequencing can be used effectively for mycobacteria species identification as a supplement to 16S rDNA sequence analysis

Epidemiology of Extrapulmonary Tuberculosis among Inpatients, China, 2008–2017

We investigated the epidemiology of extrapulmonary tuberculosis (TB) among patients admitted to Beijing Chest Hospital, Beijing, China, during January 2008–December 2017. Of 19,279 hospitalized TB patients, 33.4% (6,433) had extrapulmonary TB and 66.6% (12,846) had pulmonary TB. The most frequent forms of extrapulmonary TB observed were skeletal TB (41.1%) and pleural TB (26.0%). Younger, female patients from rural areas were more likely to have extrapulmonary TB. However, patients with diabetes mellitus were less likely to have extrapulmonary TB compared with patients without diabetes. A higher proportion of multidrug-resistant (MDR) TB was observed among patients with extrapulmonary TB than among patients with pulmonary TB. We observed a large increase in MDR TB, from 17.3% to 35.7%, for pleural TB cases. The increasing rate of drug resistance among extrapulmonary TB cases highlights the need for drug susceptibility testing and the formulation of more effective regimens for extrapulmonary TB treatment

Rifabutin Resistance Associated with Double Mutations in rpoB Gene in Mycobacterium tuberculosis Isolates

The objective of this study was to investigate the cross-resistance between rifampin (RIF) and rifabutin (RFB) among clinical Mycobacterium tuberculosis (MTB) isolates, and the correlations between specific rpoB mutations and the minimum inhibitory concentrations (MICs) of RIF and RFB. A total of 256 RIF-resistant isolates were included from the National Tuberculosis Clinical Laboratory in China. The MICs of MTB isolates against RIF and RFB were determined by using a microplate alamarBlue assay. In addition, all the MTB isolates were sequenced for mutations in rpoB gene. 204 out of 256 isolates (79.7%) were resistant to RFB, whereas 52 (20.3%) were susceptible to RFB. RIF-resistant/INH-susceptible (RR) group had a significant lower proportion of RFB-resistance than MDR- (P = 0.04) and XDR-TB group (P < 0.01). DNA sequencing revealed that there were 218 isolates (85.2%) with a single mutation, 26 (10.1%) with double mutations, and 12 (4.7%) without mutation in rpoB gene. Notably, although the single substitution of Leu511Pro, Asp516Gly, and His526Asn did not result in RFB resistance, 77.8% (7/9) of the MTB isolates with these double mutations became resistant to RFB. Compared with RR group (38.9%, 7/18), MDR-TB (63.5%, 106/167) had significantly higher proportion of isolates with mutations in codon 531 of rpoB gene (P = 0.04). Our data demonstrate that various rpoB mutations are associated with differential resistance to RIF and RFB. A single specific mutation in codons 511, 516, 526, and 533 was linked to the susceptibility to RFB for MTB, while the strains with these double mutations irrelevantly conferring RFB resistance produced RFB-resistant phenotype

Bedaquiline resistance pattern in clofazimine-resistant clinical isolates of tuberculosis patients

ABSTRACT: Objectives: Bedaquiline (BDQ) is a potent drug for treating drug-resistant tuberculosis (TB). Here, we analysed the resistance profiles of BDQ in CFZ-resistant clinical isolates and investigated the clinical risk factors of BDQ and CFZ cross/co-resistance. Methods: The AlarmarBlue microplate assay was performed to determine the minimum inhibitory concentration (MIC) of the CFZ-resistant Mycobacterium tuberculosis (MTB) clinical isolates to CFZ and BDQ. The clinical characteristics of the respective patients were analysed to explore the possible risk factors of BDQ resistance. The drug-resistance-associated genes including Rv0678, Rv1979c, atpE, pepQ and Rv1453 were sequenced and analysed. Results: A total of 72 clinical CFZ-resistant MTB isolates were collected; among these, half were identified as BDQ-resistant. The MIC value of BDQ closely correlated with CFZ (Spearman's q = 0.766, P < 0.005). Among the isolates with a MIC of CFZ ≥4 mg/L, 92.31% (12/13) were resistant to BDQ. Pre-XDR and exposure to BDQ or CFZ are the major risk factors for concurrent BDQ resistance. Among the 36 cross/co-resistant isolates, 50% (18/36) had mutations in Rv0678, 8.3% (3/36) had mutations in Rv0678+Rv1453, 5.6% (2/36) had mutations in Rv0678+Rv1979c, 2.8% (1/36) had mutations in Rv0678+Rv1979c+Rv1453, 2.8% (1/36) had mutations in atpE+Rv0678+Rv1453, 2.8% (1/36) had mutations in Rv1979c, and 27.7% (10/36) had no variations in the target genes. Conclusion: Nearly half of the CFZ-resistant isolates were still sensitive to BDQ, whereas this rate dramatically decreased among patients with pre-XDR TB or those who had been exposed to BDQ or CFZ