Treatment outcomes of patients with multidrug and extensively drug-resistant tuberculosis in Zhejiang, China.

BACKGROUND: The aim of this study was to assess the treatment outcomes of multidrug and extensively drug-resistant tuberculosis (M/XDR-TB) in Zhejiang, China and to evaluate possible risk factors associated with poor outcomes of M/XDR-TB. METHODS: Two-hundred-and-sixty-two patients having M/XDR-TB who received the diagnosis and treatment at nine referral hospitals from 1 January 2016 to 31 December 2016 in Zhejiang, China were included. All patients received second-line regimens recommended by WHO under the DOTS-Plus strategy. RESULTS: Among the 262 patients, the treatment success rate was 55.34% (n = 145) with 53.44% (n = 140) cured and 1.91% (n = 5) who completed treatment, 62 (23.66%) failed, 27 (10.31%) died, 16 (6.11%) defaulted and 12 (4.58%) transferred out. Forty (64.52%) of the 62 M/XDR-TB patients who failed treatment were due to adverse effects in the first 10 months of treatment. Eighteen patients (6.37%) had XDR-TB. Treatment failure was significantly higher among patients with XDR-TB at 50% than that among patients with non-XDR-TB at 21.72% (P = 0.006). Failure outcomes were associated with a baseline weight less than 50 kg (OR, 8.668; 95% CI 1.679-44.756; P = 0.010), age older than 60 years (OR, 9.053; 95% CI 1.606-51.027; P = 0.013), hemoptysis (OR, 8.928; 95% CI 1.048-76.923; P = 0.045), presence of cavitary diseases (OR, 10.204; 95% CI 2.032-52.631; P = 0.005), or treatment irregularity (OR, 47.619; 95% CI 5.025-500; P = 0.001). CONCLUSION: Treatment outcomes for M/XDR-TB under the DOTS-Plus strategy in Zhejiang, China were favorable but still not ideal. Low body weight (< 50 kg), old age (> 60 years), severe symptoms of TB including cavitary disease, hemoptysis and irregular treatment were independent prognostic factors for failure outcomes in patients with M/XDR-TB.

Tuberculosis: An Overview of the Immunogenic Response, Disease Progression, and Medicinal Chemistry Efforts in the Last Decade toward the Development of Potential Drugs for Extensively Drug-Resistant Tuberculosis Strains.

Tuberculosis (TB) is a slow growing, potentially debilitating disease that has plagued humanity for centuries and has claimed numerous lives across the globe. Concerted efforts by researchers have culminated in the development of various strategies to combat this malady. This review aims to raise awareness of the rapidly increasing incidences of multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis, highlighting the significant modifications that were introduced in the TB treatment regimen over the past decade. A description of the role of pathogen-host immune mechanisms together with strategies for prevention of the disease is discussed. The struggle to develop novel drug therapies has continued in an effort to reduce the treatment duration, improve patient compliance and outcomes, and circumvent TB resistance mechanisms. Herein, we give an overview of the extensive medicinal chemistry efforts made during the past decade toward the discovery of new chemotypes, which are potentially active against TB-resistant strains.

Tuberculosis: An Update on Pathophysiology, Molecular Mechanisms of Drug Resistance, Newer Anti-TB Drugs, Treatment Regimens and Host- Directed Therapies.

Human tuberculosis (TB) is primarily caused by Mycobacterium tuberculosis (Mtb) that inhabits inside and amidst immune cells of the host with adapted physiology to regulate interdependent cellular functions with intact pathogenic potential. The complexity of this disease is attributed to various factors such as the reactivation of latent TB form after prolonged persistence, disease progression specifically in immunocompromised patients, advent of multi- and extensivelydrug resistant (MDR and XDR) Mtb strains, adverse effects of tailor-made regimens, and drug-drug interactions among anti-TB drugs and anti-HIV therapies. Thus, there is a compelling demand for newer anti-TB drugs or regimens to overcome these obstacles. Considerable multifaceted transformations in the current TB methodologies and molecular interventions underpinning hostpathogen interactions and drug resistance mechanisms may assist to overcome the emerging drug resistance. Evidently, recent scientific and clinical advances have revolutionised the diagnosis, prevention, and treatment of all forms of the disease. This review sheds light on the current understanding of the pathogenesis of TB disease, molecular mechanisms of drug-resistance, progress on the development of novel or repurposed anti-TB drugs and regimens, host-directed therapies, with particular emphasis on underlying knowledge gaps and prospective for futuristic TB control programs.

Multidrug and Extensively Drug-resistant Tuberculosis: Epidemiology, Clinical Features, Management and Treatment.

Multidrug-resistant tuberculosis (MDR-TB) is a growing global public health threat. MDR-TB affects more than a half-million people worldwide and is characterized by significant morbidity and mortality. New rapid diagnostic methods like GeneXpert and availability of new MDR-TB drugs and shorter treatment regimens hold promise of more patients diagnosed and put on treatment. Major challenges of lack of adequate resources, poverty, and limited access to health care continue to hamper efforts. This article reviews epidemiology, clinical features, management, and treatment, with new updates and recent changes in guidelines that offer patients better tolerated and shorter regimens for enabling therapeutic outcomes.

A significant therapeutic effect of silymarin administered alone, or in combination with chemotherapy, in experimental pulmonary tuberculosis caused by drug-sensitive or drug-resistant strains: In vitro and in vivo studies.

For many years, tuberculosis (TB) has been a major public health problem worldwide. Advances for treatment and eradication have been very limited. Silymarin (Sm) is a natural product with antioxidant and hepatoprotective activities that has been proposed as a complementary medicine to reduce the liver injury produced by the conventional anti-TB chemotherapy. Sm also has immunoregulatory and microbicide properties. In this study, we determined the effect of Sm on the growth control of mycobacteria. In vitro studies showed that Sm and Silibinin (the principal active compound of Sm) have microbicidal activity against drug-sensitive and multidrug-resistant (MDR) mycobacteria, induce the production of protective cytokines from infected macrophages, and improve the growth control of mycobacteria (p ≤ 0.0001). Studies in vivo using a model of progressive pulmonary TB in BALB/c mice infected with drug-sensitive or MDR mycobacteria have shown that Sm induces significant expression of Th-1 cytokines such as IFN-γ and IL-12 as well as TNFα, which produce significant therapeutic activity when administered alone and apparently have a synergistic effect with chemotherapy. These results suggest that Sm has a bactericidal effect and can contribute to the control and establishment of a TH1 protective immune response against mycobacterial infection. Thus, it seems that this flavonoid has a promising potential as adjuvant therapy in the treatment of TB.

Ample glycosylation in membrane and cell envelope proteins may explain the phenotypic diversity and virulence in the Mycobacterium tuberculosis complex.

Multiple regulatory mechanisms including post-translational modifications (PTMs) confer complexity to the simpler genomes and proteomes of Mycobacterium tuberculosis (Mtb). PTMs such as glycosylation play a significant role in Mtb adaptive processes. The glycoproteomic patterns of clinical isolates of the Mycobacterium tuberculosis complex (MTBC) representing the lineages 3, 4, 5 and 7 were characterized by mass spectrometry. A total of 2944 glycosylation events were discovered in 1325 proteins. This data set represents the highest number of glycosylated proteins identified in Mtb to date. O-glycosylation constituted 83% of the events identified, while 17% of the sites were N-glycosylated. This is the first report on N-linked protein glycosylation in Mtb and in Gram-positive bacteria. Collectively, the bulk of Mtb glycoproteins are involved in cell envelope biosynthesis, fatty acid and lipid metabolism, two-component systems, and pathogen-host interaction that are either surface exposed or located in the cell wall. Quantitative glycoproteomic analysis revealed that 101 sites on 67 proteins involved in Mtb fitness and survival were differentially glycosylated between the four lineages, among which 64% were cell envelope and membrane proteins. The differential glycosylation pattern may contribute to phenotypic variabilities across Mtb lineages. The study identified several clinically important membrane-associated glycolipoproteins that are relevant for diagnostics as well as for drug and vaccine discovery.

Feature selection and prediction of treatment failure in tuberculosis.

BACKGROUND: Tuberculosis is a major cause of morbidity and mortality in the developing world. Drug resistance, which is predicted to rise in many countries worldwide, threatens tuberculosis treatment and control. OBJECTIVE: To identify features associated with treatment failure and to predict which patients are at highest risk of treatment failure. METHODS: On a multi-country dataset managed by the National Institute of Allergy and Infectious Diseases we applied various machine learning techniques to identify factors statistically associated with treatment failure and to predict treatment failure based on baseline demographic and clinical characteristics alone. RESULTS: The complete-case analysis database consisted of 587 patients (68% males) with a median (p25-p75) age of 40 (30-51) years. Treatment failure occurred in approximately one fourth of the patients. The features most associated with treatment failure were patterns of drug sensitivity, imaging findings, findings in the microscopy Ziehl-Nielsen stain, education status, and employment status. The most predictive model was forward stepwise selection (AUC: 0.74), although most models performed at or above AUC 0.7. A sensitivity analysis using the 643 original patients filling the missing values with multiple imputation showed similar predictive features and generally increased predictive performance. CONCLUSION: Machine learning can help to identify patients at higher risk of treatment failure. Closer monitoring of these patients may decrease treatment failure rates and prevent emergence of antibiotic resistance. The use of inexpensive basic demographic and clinical features makes this approach attractive in low and middle-income countries.

Retrospective study of clinical and lesion characteristics of patients undergoing surgical treatment for Pulmonary Tuberculosis in Georgia.

OBJECTIVES: Our aim was to retrospectively compare clinical data and characteristics of removed lesions of the cohort of patients undergoing therapeutical surgery for their tuberculosis. DESIGN AND METHODS: Demographic and epidemiological details, clinical data, data on the surgery performed, macroscopic characteristics of the TB lesions removed, and outcome were recorded retrospectively from the 137 patients who underwent therapeutical surgery for their TB in Tbilisi, Georgia during 2014 and 2015. RESULTS: Men represented 70% of the included patients, presented more comorbidities and underwent operation earlier in terms of days between diagnostic and surgery. Women underwent operation at younger ages, and in MDR/XDR-TB cases, showed higher percentages of sputum conversion at >2 months and of fresh necrosis in the surgical specimens, suggesting a worse evolution. Half of cases were MDR/XDR-TB cases. In spite of being considered microbiologically cured according to WHO, a non despricable percentage of cases showed viable bacilli in the surgical specimen. Even if no causality could be statistically demonstrated, differences could be encountered according to gender and drug susceptibility of the responsible strains. CONCLUSIONS: According to our results, host factors such as gender, type of necrosis found in the lesions, size of lesions and presence of viable bacilli in the surgical specimen, should be included in future studies on therapeutical surgery of TB. As most of studies are done in MDR/XDR-TB, more data on DS-TB operated cases are needed. Our results also highlight that, in spite of achieving the microbiologically cured status, sterilization might not occur, and thus new biomarkers and new methods to evaluate the healing process of TB patients are urgently needed and radiological assays should be taken into account.

Lipid transport in Mycobacterium tuberculosis and its implications in virulence and drug development.

Tuberculosis is still a major health problem worldwide and one of the main causes of death by a single infectious agent. Only few drugs are really effective to treat tuberculosis, hence, the emergence of multiple, extensively, and totally drug resistant bacilli compromises the already difficult antituberculosis treatments. Given the persistent global burden of tuberculosis, it is crucial to understand the underlying mechanisms required for the pathogenicity of Mycobacterium tuberculosis (Mtb), the causal agent of tuberculosis, in order to pave the way for developing better drugs and strategies to treat and prevent tuberculosis. The exclusive mycobacterial cell wall lipids such as trehalose monomycolate and dimycolate (TMM, TDM), phthiocerol dimycocerosate (PDIM), sulpholipid-1 (SL-1), diacyl trehalose (DAT), and pentacyl trehalose (PAT), among others, are known to play an important role in pathogenesis; thus, proteins responsible for their transport are potential virulence factors. MmpL and MmpS proteins mediate transport of important cell wall lipids across the mycobacterial membrane. In Mtb, MmpL3, MmpL7 and MmpL8 transport TMM, PDIM and SL-1 respectively. The translocation of DAT and biosynthesis of PAT is likely due to MmpL10. MmpL and MmpS proteins are involved in other processes such as drug efflux (MmpL5 and MmpL7), siderophore export (MmpL4/MmpS4 and MmpL5/MmpS5), and heme uptake (MmpL3 and MmpL11). Altogether, these proteins can be regarded as new potential targets for antituberculosis drug development. We will review recent advances in developing inhibitors of MmpL proteins, in the challenging context of targeting membrane proteins and the future prospects for potential antituberculosis drug candidates.

Risk factors associated with default from multi- and extensively drug-resistant tuberculosis treatment, Uzbekistan: a retrospective cohort analysis.

BACKGROUND: The Médecins Sans Frontières project of Uzbekistan has provided multidrug-resistant tuberculosis treatment in the Karakalpakstan region since 2003. Rates of default from treatment have been high, despite psychosocial support, increasing particularly since programme scale-up in 2007. We aimed to determine factors associated with default in multi- and extensively drug-resistant tuberculosis patients who started treatment between 2003 and 2008 and thus had finished approximately 2 years of treatment by the end of 2010. METHODS: A retrospective cohort analysis of multi- and extensively drug-resistant tuberculosis patients enrolled in treatment between 2003 and 2008 compared baseline demographic characteristics and possible risk factors for default. Default was defined as missing ≥60 consecutive days of treatment (all drugs). Data were routinely collected during treatment and entered in a database. Potential risk factors for default were assessed in univariate analysis using chi-square test and in multivariate analysis with logistic regression. RESULTS: 20% (142/710) of patients defaulted after a median of 6 months treatment (IQR 2.6-9.9). Factors associated with default included severity of resistance patterns (pre-extensively drug-resistant/extensively drug-resistant tuberculosis adjusted odds ratio 0.52, 95%CI: 0.31-0.86), previous default (2.38, 1.09-5.24) and age >45 years (1.77, 1.10-2.87). The default rate was 14% (42/294) for patients enrolled 2003-2006 and 24% (100/416) for 2007-2008 enrolments (p = 0.001). CONCLUSIONS: Default from treatment was high and increased with programme scale-up. It is essential to ensure scale-up of treatment is accompanied with scale-up of staff and patient support. A successful first course of tuberculosis treatment is important; patients who had previously defaulted were at increased risk of default and death. The protective effect of severe resistance profiles suggests that understanding disease severity or fear may motivate against default. Targeted health education and support for at-risk patients after 5 months of treatment when many begin to feel better may decrease default.

New insights into the pathogenesis of tuberculosis revealed by Mycobacterium marinum: the zebrafish model from the systems biology perspective.

Tuberculosis remains a worldwide health concern, largely due to the emergence of multi-drug-resistant (MDR) and extensive-drug-resistant (XDR) Mycobacterium tuberculosis co-infection with HIV. The exact mechanism of Mycobacterium virulence, pathogenesis, and persistence is not fully understood. The hallmark of tuberculosis, granulomas are promoted by Mycobacterium virulence factors, and they have long been considered a structural advantage to the host. However, this traditional view has been challenged recently, largely due to the evidence originating from the M. marinum-zebrafish model. As a genetically tractable model, zebrafish provide unprecedented opportunities to address the pathogenesis of tuberculosis from a systems biology perspective. The latest data from this model are summarized in this review, special attention is given to the shared pathway and network between zebrafish and humans. This research serves to deepen our understanding of this complex process and to promote the discovery of better countermeasures against tuberculosis.

Efficacy and safety of linezolid in the treatment of extensively drug-resistant tuberculosis.

Linezolid is a new antibiotic with activity against Mycobacterium tuberculosis in vitro and in vivo. This study aims to evaluate the efficacy and safety of linezolid in the treatment of extensively drug-resistant tuberculosis (XDR-TB). We used a linezolid-containing regimen in the treatment of 14 XDR-TB patients. Two years of individualized chemotherapy regimens were adopted on the basis of the patients'medication history and the results of drug susceptibility testing. The patients received 600 mg of linezolid twice a day for the first 1-2 months, followed by once a day thereafter. Eleven patients (78.6%) showed significant improvement in clinical symptoms. Chest computed tomography revealed that 10 patients (71.4%) showed cavity closure. Smear conversion and culture conversion were achieved in all 14 patients (100%) with an average of 64 and 63 days, respectively. The exact proportions of serious and minor adverse events determined by linezolid were 21.4% (3/14) and 64.3% (9/14), respectively. These data show that linezolid-containing chemotherapy for the treatment of XDR-TB may significantly improve clinical symptoms, promote lesion absorption and cavity closure, and accelerate sputum conversion. Further, adverse reactions can be tolerated and resolved with suitable intervention.

Extensively drug-resistant tuberculosis at a tuberculosis specialist hospital in Shanghai, China: clinical characteristics and treatment outcomes.

BACKGROUND: Extensively drug-resistant tuberculosis (XDR-TB) has recently emerged as a global public health problem. The objective of this study was to investigate the clinical characteristics, management and outcomes of human immunodeficiency virus-negative patients with XDR-TB at a specialist TB hospital in Shanghai, China. METHODS: From July 2007 to June 2009 we analyzed TB patients with culture-proven XDR-TB at a specialist TB hospital in Shanghai. RESULTS: Among 1156 TB cases, all culture-positive for Mycobacterium tuberculosis complex, 494 cases (42.7%) were classified as MDR-TB; 126 cases (10.9%) were XDR-TB. At least 3 lung fields were involved in 90.5% of XDR-TB patients and in 80.7% of other MDR-TB patients (p = 0.008). Of the XDR-TB cases, 40.5% were complicated by diabetes and other diseases, significantly higher compared with the other MDR-TB cases (p = 0.002). The rates of resistance to all drugs except isoniazid and rifampicin were significantly higher in patients with XDR-TB than in patients with other MDR-TB (p < 0.001). Treatment failure was more common in patients with XDR-TB than in those with other MDR-TB (p < 0.001), whereas the mortality and default rates did not differ significantly. CONCLUSIONS: The prevalence of XDR-TB is high in some areas of China. The clinical treatment outcome for XDR-TB is usually very poor.

Clinical and genotypic characteristics of extensively drug-resistant and multidrug-resistant tuberculosis.

The aims of this study were to compare the clinical features of patients with extensively drug-resistant tuberculosis (XDRTB) and multidrug-resistant tuberculosis (MDRTB) and the genotypic characteristics of these Mycobacterium tuberculosis isolates. A total of 90 non-HIV-infected patients having MDRTB (n = 80, not including XDRTB, 88.9%) and XDRTB (n = 10, 11.1%) were identified from 2000 to 2007. Genotypes of the 39 available isolates were evaluated by spoligotyping and the 24-locus mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) scheme. Patients with XDRTB were more likely to have previous history of TB and cavitary lung lesions than patients with MDRTB (P < 0.05). Among the 39 isolates for spoligotyping analysis, the Beijing genotype was the most common (n = 21, 53.8%). Four (44.4%) isolates of XDRTB and 17 (56.7%) isolates of MDRTB belonged to Beijing family genotypes. There was no significant difference in the anti-tuberculosis drug resistance rates between Beijing and non-Beijing genotype isolates or in the clinical features of infected patients. In conclusion, significant differences in clinical manifestations existed among patients with XDRTB and MDRTB. The clinical features of patients infected with the Beijing genotype and the drug resistance profile of the Beijing genotype isolates were similar to those for the non-Beijing family genotype.