Multidrug-resistant Tuberculosis

Design, synthesis and computational studies of new azaheterocyclic coumarin derivatives as anti-Mycobacterium tuberculosis agents targeting enoyl acyl carrier protein reductase (InhA)

In this study, we designed and synthesized a series of coumarin derivatives as antitubercular agents targeting the enoyl acyl carrier protein reductase (InhA) enzyme. Among the synthesized compounds, the tetrazole derivative 4c showed the most potent antitubercular effect with a minimum inhibitory concentration value (MIC) of 15 μg mL-1 against Mtb H37Rv and could also inhibit the growth of the mutant strain (ΔkatG). Compound 4c was able to penetrate Mtb-infected human macrophages and suppress the intracellular growth of tubercle bacilli. Moreover, the target derivative 4c showed a potent inhibitory effect against InhA enzyme with an IC50 value of 0.565 μM, which was superior to the reference InhA inhibitor triclosan. Molecular docking of compound 4c within the InhA active site revealed the importance of the 4-phenylcoumarin ring system and tetrazole moiety for activity. Finally, the physicochemical properties and pharmacokinetic parameters of 4c were investigated.

Whole-genome sequencing and Mycobacterium tuberculosis: Challenges in sample preparation and sequencing data analysis

The numbers of patients with tuberculosis (TB) caused by resistant strains are still alarming. Therefore, it is necessary to determine resistance more quickly and precisely, than it is with the currently used phenotypic and genotypic methods. In recent years, technological advances have been made and the whole-genome sequencing (WGS) method has been introduced as a part of routine diagnostics in clinical laboratories. Comparing a wide range of mycobacterial genomic variations with a reference genome leads to a consistent evaluation of molecular-epidemiology and resistance of Mycobacterium tuberculosis (M. tuberculosis) to a wide range of anti-TB drugs. The quality of the obtained sequencing data is closely related to the type of sample and the method used for DNA extraction and sequencing library preparation. Moreover, the correct interpretation of results is also influenced by a bioinformatic data processing. A large number of bioinformatics pipelines are currently available, the sensitivity of which varies due to the different sizes of databases containing relevant mutations. This review focuses on the individual steps included in the sequencing workflow and factors that may affect the interpretation of final results.

Trends in multidrug-resistant tuberculosis in Tehran, Iran: an analysis of published data

Introduction: Multidrug-resistant tuberculosis (MDR-TB) is one of the major public health threats especially in developing countries. In Iran, the emergence and spread of MDR-TB are likely to pose a significant problem for the National Tubeculosis Control Program (NTP). In this study, to determine the trend of MDR-TB in Tehran, the results of published studies were analyzed.

Methods: Several databases were searched, including Medline, Embase, Web of Science and Iranian databases. Studies which report the prevalence of MDR-TB by World Health Organization (WHO)-endorsed drug susceptibility testing (DST) methods were included in the study. Data were analyzed with SPSS 20 (SPSS, Chicago, Illinois, USA).

Results: Analysis of the MDR-TB trend did not show any increase among new TB cases, but the trend of MDR-TB was significantly increased among previously treated cases. The prevalence of MDR-TB from 48.0% in 1996 reached 58.0% in 2004 (P<0.05).

Conclusions: Our analysis shows an increasing trend in MDR-TB, particularly in retreatment cases. This study strongly highlights the need to develop further strategies for surveillance, monitoring, and management of MDR-TB cases.

Whole-Genome Sequencing in Relation to Resistance of Mycobacterium Tuberculosis

Tuberculosis, a disease caused by Mycobacterium tuberculosis, represents one of the deadliest infections worldwide. The incidence of resistant forms is increasing year by year; therefore, it is necessary to involve new methods for rapid diagnostics and treatment. One of the possible solutions is the use of whole-genome sequencing (WGS).

The WGS provides an identification of complete genome of the microorganism, including all genes responsible for resistance, in comparison with other genotypic methods (eg. Xpert MTB / RIF or Hain line-probes) that are capable to detect only basic genes. WGS data are available in 1-9 days and several online software tools (TBProfiler, CASTB, Mykrobe PredictorTB) are used for their interpretation and analysis, compared to 3-8 weeks in the case of classic phenotypic evaluation.

Furthermore, WGS predicts resistance to the first-line antituberculotics with a sensitivity of 85-100% and a specificity of 85-100%.

This review elucidates the importance and summarizes the current knowledge about the possible use of WGS in diagnosis and treatment of resistant forms of tuberculosis elucidates.

WGS of M. tuberculosis brings new possibilities for rapid and accurate diagnostics of resistant forms of tuberculosis. Introducing WGS into routine practice can help to reduce the spread of resistant forms of tuberculosis as well as to increase the success rate of the treatment, especially through an appropriate combination of antituberculotics ATs. Introduction of WGS into routine diagnostics can, in spite of the financial difficulty, significantly improve patient care.

Bis-spirochromanones as potent inhibitors of Mycobacterium tuberculosis: synthesis and biological evaluation

On the basis of reported antimycobacterial property of chroman-4-one pharmacophore, a series of chemically modified bis-spirochromanones were synthesized starting from 2-hydroxyacetophenone and 1,4-dioxaspiro[4.5] decan-8-one using a Kabbe condensation approach. The synthesized bis-spirochromanones were established based on their spectral data and X-ray crystal structure of 6e. All synthesized compounds were evaluated against Mycobacterium tuberculosis H37Rv (ATCC 27294) strain, finding that some products exhibited good antimycobacterial activity with minimum inhibitory concentration as low as [Formula: see text]. Docking studies were carried out to identify the binding interactions of compounds II, 6a and 6n with FtsZ. Compounds exhibiting good in vitro potency in the MTB MIC assay were further evaluated for toxicity using the HEK cell line.

The reliability of rifampicin resistance as a proxy for multidrug-resistant tuberculosis: a systematic review of studies from Iran

In Iran, patients showing rifampicin (RIF) resistance detected by the Xpert® MTB/RIF assay are considered as candidates for multidrug-resistant tuberculosis (MDR-TB) treatment. Despite the fact that RIF resistance has been used as a proxy for MDR-TB, little is known about the proportion of isoniazid (INH) resistance patterns in RIF-resistant TB. We systematically searched MEDLINE, Embase, and other databases up to March 2017 for studies addressing the proportion of INH resistance patterns in RIF-resistant TB in Iran. The data were pooled using a random effects model. Heterogeneity was assessed using Cochran's Q and I² statistics. A total of 11 articles met the eligibility criteria. Data analysis demonstrated that 33.3% of RIF-resistant isolates from new TB cases and 14.8% of RIF-resistant isolates from previously treated cases did not display resistance to INH. The relatively high proportion of INH susceptibility among isolates with RIF resistance indicated that RIF resistance may no longer predict MDR-TB in Iran. Therefore, the detection of RIF resistance by the Xpert MTB/RIF assay will require complementary detection of INH resistance by other drug susceptibility testing (DST) methods in order to establish the diagnosis of MDR-TB.

Pathology of infectious diseases: what does the future hold?

The demand for expertise in pathology for the diagnosis of infectious diseases (ID) is continually growing, due to an increase in ID in immunocompromised patients and in the (re)-emergence of common and uncommon diseases, including tropical infections and infections with newly identified microbes. The microbiology laboratory plays a crucial role in diagnosing infections, identifying the responsible infectious agents and establishing sensitivity of pathogens to drug therapy. Pathology, however, is the only way to correlate the presence of an infectious agent with the reaction it evokes at cell and tissue level. For pathologists working in the field of ID pathology, it is essential to dispose of competence in cell and tissue pathology as well as in microbiology. Expertise in ID includes understanding of taxonomy and classification of pathogens as well as morphological criteria supporting their identification. Moreover, ID pathologists must master the methods used to detect pathogens in fixed cell and tissue samples, notably immunohistochemistry, in situ hybridization and the polymerase chain reaction. Paradoxically, the increasing frequency of lesions caused by pathogens and diagnosed in a pathology laboratory appears to be paralleled by a gradual loss of expertise of pathologists in the field of infectious and tropical diseases. We contend that this may be due at least in part to the continuously increasing number of samples of tumor tissue pathologists deal with and the rapidly expanding number of tissue based biomarkers with predictive value for new anti-cancer therapies. In this review, we highlight current and future issues pertaining to ID pathology, in order to increase awareness of its importance for surgical and molecular pathology. The intention is to contribute to the development of best practice in ID pathology.

The Prevalence of Drug-Resistant Tuberculosis in Mainland China: An Updated Systematic Review and Meta-Analysis

Background

In recent years, drug resistant tuberculosis (DR-TB) particularly the emergence of multi-drug-resistant tuberculosis (MDR-TB) has become a major public health issue. The most recent study regarding the prevalence of drug-resistant tuberculosis in mainland China was a meta-analysis published in 2011, and the subjects from the included studies were mostly enrolled before 2008, thus making it now obsolete. Current data on the national prevalence of DR-TB is needed. This review aims to provide a comprehensive and up-to-date assessment of the status of DR-TB epidemic in mainland China.

Methods

A systematic review and meta-analysis of studies regarding the prevalence of drug-resistant tuberculosis in mainland China was performed. Pubmed/MEDLINE, EMBASE, the Cochrane central database, the Chinese Biomedical Literature Database and the China National Knowledge Infrastructure Database were searched for studies relevant to drug-resistant tuberculosis that were published between January 1, 2012 and May 18, 2015. Comprehensive Meta-Analysis (V2.2, Biostat) software was used to analyse the data.

Results

A total of fifty-nine articles, published from 2012 to 2015, were included in our review. The result of this meta-analysis demonstrated that among new cases, the rate of resistance to any drug was 20.1% (18.0%–22.3%; n/N = 7203/34314) and among retreatment cases, the rate was 49.8% (46.0%–53.6%; n/N = 4155/8291). Multi-drug resistance among new and retreatment cases was 4.8% (4.0%–5.7%; n/N = 2300/42946) and 26.3% (23.1%–29.7%; n/N = 3125/11589) respectively. The results were significantly heterogeneous (p<0.001, I² tests). Resistance to isoniazid was the most common resistance observed, and HRSE (H: isoniazid; R: rifampicin; S: streptomycin; E: ethambutol) was the most common form for MDR among both new and retreatment cases. Different drug resistance patterns were found by subgroup analysis according to geographic areas, subject enrolment time, and methods of drug susceptibility test (DST).

Conclusions

The prevalence of resistance to any drug evidently dropped for both new and retreatment cases, and multi-drug resistance declined among new cases but became more prevalent among retreatment cases compared to the data before 2008. Therefore, drug-resistant tuberculosis, particularly multi-drug-resistant tuberculosis among retreatment TB cases is a public health issue in China that requires a constant attention in order to prevent increase in MDR-TB cases.

MRP8/14 induces autophagy to eliminate intracellular Mycobacterium bovis BCG

OBJECTIVE

To explore the role of myeloid-related protein 8/14 in mycobacterial infection.

METHODS

The mRNA and protein expression levels of MRP8 or MRP14 were measured by real-time PCR and flow cytometry, respectively. Role of MRP8/14 was tested by overexpression or RNA interference assays. Flow cytometry and colony forming unit were used to test the phagocytosis and the survival of intracellular Mycobacterium bovis BCG (BCG), respectively. Autophagy mediated by MRP8/14 was detected by Western blot and immunofluorescence. The colocalization of BCG phagosomes with autophagosomes or lysosomes was by detected by confocal microscopy. ROS production was detected by flow cytometry.

RESULTS

MRP8/14 expressions were up-regulated in human monocytic THP1 cells and primary macrophages after mycobacterial challenge. Silencing of MRP8/14 suppressed bacterial killing, but had no influence on the phagocytosis of BCG. Importantly, silencing MRP8/14 decreased autophagy and BCG phagosome maturation in THP1-derived macrophages, thereby increasing the BCG survival. Additionally, we demonstrated that MRP8/14 promoted autophagy in a ROS-dependent manner.

CONCLUSIONS

The present study revealed a novel role of MRP8/14 in the autophagy-mediated elimination of intracellular BCG by promoting ROS generation, which may provide a promising therapeutic target for tuberculosis and other intracellular bacterial infectious diseases.

Emerging and reemerging neglected tropical diseases: a review of key characteristics, risk factors, and the policy and innovation environment

In global health, critical challenges have arisen from infectious diseases, including the emergence and reemergence of old and new infectious diseases. Emergence and reemergence are accelerated by rapid human development, including numerous changes in demographics, populations, and the environment. This has also led to zoonoses in the changing human-animal ecosystem, which are impacted by a growing globalized society where pathogens do not recognize geopolitical borders. Within this context, neglected tropical infectious diseases have historically lacked adequate attention in international public health efforts, leading to insufficient prevention and treatment options. This subset of 17 infectious tropical diseases disproportionately impacts the world's poorest, represents a significant and underappreciated global disease burden, and is a major barrier to development efforts to alleviate poverty and improve human health. Neglected tropical diseases that are also categorized as emerging or reemerging infectious diseases are an even more serious threat and have not been adequately examined or discussed in terms of their unique risk characteristics. This review sets out to identify emerging and reemerging neglected tropical diseases and explore the policy and innovation environment that could hamper or enable control efforts. Through this examination, we hope to raise awareness and guide potential approaches to addressing this global health concern.

Worldwide increase in diabetes: implications for tuberculosis control

Diabetes presents a greater threat to global tuberculosis (TB) control than previously appreciated, with risk of reversing the achievements of several decades. An estimated 382 million people worldwide currently have diabetes, half of whom are undiagnosed. Most live in low- and middle-income countries alongside many of the two billion individuals infected with TB. Though the frequency of TB in type 1 diabetes was known for centuries, only recently have we observed the tripling of TB in type 2 diabetes, most significantly in high-burden TB populations such as in Peru, Russia, and the People's Republic of China. In India diabetes is estimated to have increased TB cases by 46% between 1998 and 2008. Diabetes is a greater long-term threat to TB control than human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) since ten-fold more people are affected by diabetes than HIV/AIDS in larger geographic areas. Diabetes in TB increases drug resistance, treatment failure, and mortality, and may increase the spread of drug-resistant strains. Delayed or missed diagnosis fuels transmission of TB and hinders control of diabetes. Tailored treatment for diabetes patients requires well-designed clinical trials. The World Health Organization (WHO) framework for care and control of diabetes and TB needs improved screening strategies. Determination of how best to establish bi-directional screening is hampered by lack of affordable and reliable methods. Recommendations include education of health care providers, patients, and communities. Structured diabetes programs with registries and effective follow-up could be modeled on and communicate with existing TB programs. Vital research should address new diagnostic tools, lowering cost and evaluation of intervention strategies, as well as better understanding of the impaired immune responses that make diabetes patients more susceptible to TB leading to targeted therapies. Solutions will require the combination of good science, good decision-making, adequate funding, and political will.

[What place and what future for the pathology of infectious and tropical diseases in France?]

The management of tissues and cellular samples by the pathologists in the infectious and tropical diseases pathology field in 2014 needs a strong knowledge of both morphological and molecular domains which includes the good control: (i) of the taxonomy of infectious and tropical diseases pathology leading to the pathogens identification and (ii) of the ancillary methods which can be used in fixed samples in order to detect or better identify these pathogens. There is a recent paradox in France concerning the frequency of infectious diseases to be diagnosed in pathology laboratories and the progressive loss of pathologist's expertise in this domain. Different reasons could explain this statement including the omnipresence of the tumour lesions to be managed in a pathology laboratory as well as the recent constraints associated with the different biomarkers that are mandatory to be detected by immunohistochemistry and/or by molecular biology. Even if the microbiologists play a pivotal role for identifying the different pathogens as well as for the assessment of their sensitivity to the anti-microbial drugs, a large number of infectious diseases can be diagnosed only on fixed tissue and/or cells by the pathologists. The purpose of this review is to describe the current and future issues of infectious and tropical diseases diagnoses in pathology laboratories, in particular in France.

MUBII-TB-DB: a database of mutations associated with antibiotic resistance in Mycobacterium tuberculosis

Background

Tuberculosis is an infectious bacterial disease caused by Mycobacterium tuberculosis. It remains a major health threat, killing over one million people every year worldwide. An early antibiotic therapy is the basis of the treatment, and the emergence and spread of multidrug and extensively drug-resistant mutant strains raise significant challenges. As these bacteria grow very slowly, drug resistance mutations are currently detected using molecular biology techniques. Resistance mutations are identified by sequencing the resistance-linked genes followed by a comparison with the literature data. The only online database is the TB Drug Resistance Mutation database (TBDReaM database); however, it requires mutation detection before use, and its interrogation is complex due to its loose syntax and grammar.

Description

The MUBII-TB-DB database is a simple, highly structured text-based database that contains a set of Mycobacterium tuberculosis mutations (DNA and proteins) occurring at seven loci: rpoB, pncA, katG; mabA(fabG1)-inhA, gyrA, gyrB, and rrs. Resistance mutation data were extracted after the systematic review of MEDLINE referenced publications before March 2013. MUBII analyzes the query sequence obtained by PCR-sequencing using two parallel strategies: i) a BLAST search against a set of previously reconstructed mutated sequences and ii) the alignment of the query sequences (DNA and its protein translation) with the wild-type sequences. The post-treatment includes the extraction of the aligned sequences together with their descriptors (position and nature of mutations). The whole procedure is performed using the internet. The results are graphs (alignments) and text (description of the mutation, therapeutic significance). The system is quick and easy to use, even for technicians without bioinformatics training.

Conclusion

MUBII-TB-DB is a structured database of the mutations occurring at seven loci of major therapeutic value in tuberculosis management. Moreover, the system provides interpretation of the mutations in biological and therapeutic terms and can evolve by the addition of newly described mutations. Its goal is to provide easy and comprehensive access through a client–server model over the Web to an up-to-date database of mutations that lead to the resistance of M. tuberculosis to antibiotics.

Development of novel tetrahydrothieno[2,3-c]pyridine-3-carboxamide based Mycobacterium tuberculosis pantothenate synthetase inhibitors: molecular hybridization from known antimycobacterial leads

Twenty six 2,6-disubstituted 4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxamide derivatives were designed by molecular hybridization approach using and synthesized from piperidin-4-one by five step synthesis. Compounds were evaluated for Mycobacterium tuberculosis (MTB) pantothenate synthetase (PS) inhibition study, in vitro activities against MTB, cytotoxicity against RAW 264.7 cell line. Among the compounds, 6-(4-nitrophenylsulfonyl)-2-(5-nitrothiophene-2-carboxamido)-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxamide (11) was found to be the most active compound with IC50 of 5.87 ± 0.12 μM against MTB PS, inhibited MTB with MIC of 9.28 μM and it was non-cytotoxic at 50 μM. The binding affinity of the most potent inhibitor 11 was further confirmed biophysically through differential scanning fluorimetry.

Antibiotic treatment suppresses rotavirus infection and enhances specific humoral immunity

BACKGROUND

Rotavirus causes 500 000 deaths and millions of physician visits and hospitalizations per year, with worse outcomes and reduced vaccine efficacy in developing countries. We hypothesized that the gut microbiota might modulate rotavirus infection and/or antibody response and thus potentially play a role in such regional differences.

METHODS

The microbiota was ablated via germ-free or antibiotic approaches. Enhanced exposure to microbiota was achieved via low-dose dextran sodium sulfate (DSS) treatment. Rotavirus infection and replication was assessed by enzyme-linked immunosorbent assay (ELISA) and quantitative reverse-transcription polymerase chain reaction. Diarrhea was scored visually. Humoral responses to rotavirus were measured by ELISA and enzyme-linked immunosorbent spot assay.

RESULTS

Microbiota elimination delayed infection and reduced infectivity by 42%. Antibiotics did not alter ratios of positive-sense to negative-sense strands, suggesting that entry rather than replication was influenced. Antibiotics reduced the diarrhea incidence and duration, indicating that the reduction in the level of rotavirus antigen was biologically significant. Despite lowered antigen level, antibiotics resulted in a more durable rotavirus mucosal/systemic humoral response. Increased rotavirus antibody response durability correlated with increased small intestinal rotavirus-specific, immunoglobulin A-producing antibody-secreting cell concentration in antibiotic-treated mice. Conversely, DSS treatment impaired generation of rotavirus-specific antibodies.

CONCLUSIONS

Microbiota ablation resulted in reduced rotavirus infection/diarrhea and a more durable rotavirus antibody response, suggesting that antibiotic administration before rotavirus vaccination could raise low seroconversion rates that correlate with the vaccine's inefficacy in developing regions.