Drug-resistant tuberculosis: time for visionary political leadership

Perceived access to social support during and after TB treatment in Mbeya and Songwe regions, Tanzania: perspectives from TB patients and survivors set against health care providers

Introduction

Pulmonary tuberculosis (PTB) remains a life-threatening disease in Tanzania, with negative physical, financial, economic and psychosocial consequences to individuals and the society. It mainly lowers the quality of life of patients, survivors and their families, especially those in the poorest and socially deprived categories.

Objectives

To report and discuss a qualitative study that assessed the nature of social support desired and received by PTB patients and survivors. Participants were given a chance to share their experiences and their perceptions on whether the social support they desired had an impact on their treatment-seeking behaviour and treatment adherence.

Methods

Face-to-face interviews were conducted with the three aforementioned groups, purposively selected at a TB clinic between October 2020 and March 2021. The questions covered topics related to the types of social support desired and the sources of support during and after treatment, if any. Interviews were concluded until no new information was obtained. Data analysis was facilitated using NVivo 12 software.

Results

Participants pointed out a need for psychosocial, financial, and material support during and after treatment. However, they sometimes miss support from family/household members or the rest of the community. Because of this experience, they lived with difficulties, facing hardships when required to pay out of pocket for transport during the care-seeking. Survivors testified experience of a denial of support by even their close relatives who regarded them as no longer needing it after recovering. Patients and survivors also reported experience of social isolation as they were believed able to transmit PTB infections. Limited psychological support at the contacted TB clinics was another experience reported. TB clinic staff's experiences confirmed almost all the experiences shared by their clients. With limited support, resilience and self-care were identified as key mechanisms for coping.

Conclusion

Complete recovery from PTB is possible, but reverting to a normal life is difficult without social support. Policies and programs need to increase opportunities for social support for TB patients and survivors. Doing so is likely to improve TB-related treatment, care-seeking practices, and adherence.

Unnatural Endotype B PPAPs as Novel Compounds with Activity against Mycobacterium tuberculosis

Pre-SARS-CoV-2, tuberculosis was the leading cause of death by a single pathogen. Repetitive exposure of Mycobacterium tuberculosis(Mtb) supported the development of multidrug- and extensively drug-resistant strains, demanding novel drugs. Hyperforin, a natural type A polyprenylated polycyclic acylphloroglucinol from St. John's wort, exhibits antidepressant and antibacterial effects also against Mtb. Yet, Hyperforin's instability limits the utility in clinical practice. Here, we present photo- and bench-stable type B PPAPs with enhanced antimycobacterial efficacy. PPAP22 emerged as a lead compound, further improved as the sodium salt PPAP53, drastically enhancing solubility. PPAP53 inhibits the growth of virulent extracellular and intracellular Mtb without harming primary human macrophages. Importantly, PPAP53 is active against drug-resistant strains of Mtb. Furthermore, we analyzed the in vitro properties of PPAP53 in terms of CYP induction and the PXR interaction. Taken together, we introduce type PPAPs as a new class of antimycobacterial compounds, with remarkable antibacterial activity and favorable biophysical properties.

Unsuccessful treatment outcome and associated risk factors. A prospective study of DR-TB patients from a high burden country, Pakistan

INTRODUCTION

Tuberculosis (TB), a curable and preventable infectious disease, becomes difficult to treat if resistance against most effective and tolerable first line anti-TB drugs is developed. The objective of the present study was to evaluate the treatment outcomes and predictors of poor outcomes among drug-resistant tuberculosis (DR-TB) patients treated at a programmatic management unit of drug resistant tuberculosis (PMDT) unit, Punjab, Pakistan.

METHODS

This prospective observational study was conducted at a a PMDT unit in Multan, Punjab, Pakistan. A total of 271 eligible culture positive DR-TB patients enrolled for treatment at the study site between January 2016 and May 2017 were followed till their treatment outcomes were recorded. World Health Organization's (WHO) defined criteria was used for categorizing treatment outcomes. The outcomes of cured and treatment completed were collectively placed as successful outcomes, while death, lost to follow-up (LTFU) and treatment failure were grouped as unsuccessful outcomes. Multivariable binary logistic regression analysis was employed for getting predictors of unsuccessful treatment outcomes. A p-value <0.05 was considered statistically significant.

RESULTS

Of the 271 DR-TB patients analysed, nearly half (51.3%) were males. The patient's (Mean ± SD) age was 36.75 ± 15.69 years. A total of 69% patients achieved successful outcomes with 185 (68.2%) patients being cured and 2 (0.7%) completed therapy. Of the remaining 84 patients with unsuccessful outcomes, 48 (17.7%) died, 2 (0.7%) were declared treatment failure, 34 (12.5%) were loss to follow up. After adjusting for confounders, patients' age > 50 years (OR 2.149 (1.005-4.592) with p-value 0.048 and baseline lung cavitation (OR 7.798 (3.82-15.919) with p-value <0.001 were significantly associated with unsuccessful treatment outcomes.

CONCLUSIONS

The treatment success rate (69%) in the current study participants was below the target set by WHO (>75%). Paying special attention and timely intervention in patients with high risk of unsuccessful treatment outcomes may help in improving treatment outcomes at the study site.

Estimating the prevalence of poor-quality anti-TB medicines: a neglected risk for global TB control and resistance

OBJECTIVES

Tuberculosis (TB) remains a major global public health problem, especially with the recent emergence of multidrug-resistant TB and extensively drug-resistant TB. There has been little consideration of the extent of substandard and falsified (SF) TB medicines as drivers of resistance. We assessed the evidence on the prevalence of SF anti-TB medicines and discussed their public health impact.

MATERIALS/METHODS

We searched Web of Science, Medline, Pubmed, Google Scholar, WHO, US Pharmacopeia and Medicines Regulatory Agencies websites for publications on anti-TB medicines quality up to 31 October 2021. Publications reporting on the prevalence of SF anti-TB drugs were evaluated for quantitative analysis.

RESULTS

Of the 530 screened publications, 162 (30.6%) were relevant to anti-TB medicines quality; of those, 65 (40.1%) described one or more TB quality surveys in a specific location or region with enough information to yield an estimate of the local prevalence of poor-quality TB medicines. 7682 samples were collected in 22 countries and of those, 1170 (15.2%) failed at least one quality test. 14.1% (879/6255) of samples failed in quality surveys, 12.5% (136/1086) in bioequivalence studies and 36.9% (87/236) in accelerated biostability studies. The most frequently assessed were rifampicin monotherapy (45 studies, 19.5%) and isoniazid monotherapy (33, 14.3%), rifampicin-isoniazid-pyrazinamide-ethambutol fixed dose combinations (28, 12.1%) and rifampicin-isoniazid (20, 8.6%). The median (IQR) number of samples collected per study was 12 (1-478).

CONCLUSIONS

SF, especially substandard, anti-TB medicines are present worldwide. However, TB medicine quality data are few and are therefore not generalisable that 15.2% of global anti-TB medicine supply is SF. The evidence available suggests that the surveillance of the quality of TB medicines needs to be an integral part of treatment programmes. More research is needed on the development and evaluation of rapid, affordable and accurate portable devices to empower pharmacy inspectors to screen for anti-TB medicines.

Safety, Tolerability, Pharmacokinetics, and Metabolism of Telacebec (Q203) for the Treatment of Tuberculosis: a Randomized, Placebo-Controlled, Multiple Ascending Dose Phase 1B Trial

A phase 1b, randomized, placebo-controlled, double-blind, multiple ascending dose study (NCT02858973) was conducted to assess the safety, tolerability, and pharmacokinetics of the new antituberculosis agent telacebec (Q203). A total of 47 healthy adult subjects entered the study; 36 received telacebec, and 11 received placebo. Telacebec at doses of 20, 50, 100, 160, 250, and 320 mg was orally administered once daily with a standard meal for 14 days. Multiple oral doses of telacebec up to 320 mg daily for 14 days appeared to be safe and well tolerated by healthy adult subjects in this study. There were no deaths, serious adverse events, or subject discontinuations due to adverse events. Following oral doses of telacebec, the overall extent (AUC_τ) and peak (C_max) exposures of telacebec increased from 538.94 to 10,098.47 ng·h/mL and from 76.43 to 1502.33 ng/mL, respectively, with increasing telacebec doses from 20 mg to 320 mg. A steady state was achieved for plasma telacebec by day 12, and there was 1.9- to 3.1-fold accumulation in the extent of telacebec exposure after daily doses for 14 days. Analysis of plasma samples from the participants indicated that telacebec was the primary circulating entity with no significant metabolites. Three potential metabolites of telacebec have been identified, which may be relatively minimal compared to the parent drug. Consistent with findings from preclinical and previous single-dose clinical studies, these results also support the potential of telacebec for further development as a safe and effective agent for the treatment of tuberculosis.

The incidence of TB and MDR-TB in pediatrics and therapeutic options: a systematic review

BACKGROUND

Tuberculosis (TB) is considered one of the top 10 causes of death worldwide and the leading cause of death from a single infectious agent. Multidrug-resistant (MDR) TB can affect people of all age groups, including children (aged 0-15 years). However, very little is known about the extent of this problem in children. This systematic review aims to investigate the incidence of TB and drug-resistant (DR) TB among the pediatric population. It also reviews the therapeutic options available to treat the condition.

METHODS

A comprehensive search for all relevant evidence was conducted. The following databases were searched: MEDLINE, CINAHL, and Web of Science. The searched time frame was limited from January 1990 to December 2020 with a focus on the incidence of TB and MDR-TB among pediatrics and the therapeutic options available.

RESULTS

A total of 537 articles were obtained via the selected databases. After title and abstract screening, 418 articles were excluded leaving 119 articles. Full-text screening was conducted on 119 articles, excluding a further 110 articles. Thus, 9 articles were subject to quality assessment and included in this review. The 9 articles represented the age group of 0-15 years and included both males and females. All studies included were of retrospective study design.

DISCUSSION

The included studies mentioned a moderate increase in TB cases among pediatrics exacerbated by malnutrition, lack of bacille Calmette-Guérin (BCG) vaccination, and human immunodeficiency virus (HIV) coinfection. MDR-TB prevalence was especially high in South Africa. Drug therapy for both TB and MDR-TB yielded favorable outcomes among pediatrics. However, one of the biggest challenges with drug therapy includes the dosage forms available.

SYSTEMATIC REVIEW REGISTRATION

DOI: 10.17605/OSF.IO/G34NF.

Deciphering Isoniazid Drug Resistance Mechanisms on Dimeric Mycobacterium tuberculosis KatG via Post-molecular Dynamics Analyses Including Combined Dynamic Residue Network Metrics

Resistance mutations in Mycobacterium tuberculosis (Mtb) catalase peroxidase protein (KatG), an essential enzyme in isoniazid (INH) activation, reduce the sensitivity of Mtb to first-line drugs, hence presenting challenges in tuberculosis (TB) management. Thus, understanding the mutational imposed resistance mechanisms remains of utmost importance in the quest to reduce the TB burden. Herein, effects of 11 high confidence mutations in the KatG structure and residue network communication patterns were determined using extensive computational approaches. Combined traditional post-molecular dynamics analysis and comparative essential dynamics revealed that the mutant proteins have significant loop flexibility around the heme binding pocket and enhanced asymmetric protomer behavior with respect to wild-type (WT) protein. Heme contact analysis between WT and mutant proteins identified a reduction to no contact between heme and residue His270, a covalent bond vital for the heme-enabled KatG catalytic activity. Betweenness centrality calculations showed large hub ensembles with new hubs especially around the binding cavity and expanded to the dimerization domain via interface in the mutant systems, providing possible compensatory allosteric communication paths for the active site as a result of the mutations which may destabilize the heme binding pocket and the loops in its vicinity. Additionally, an interesting observation came from Eigencentrality hubs, most of which are located in the C-terminal domain, indicating relevance of the domain in the protease functionality. Overall, our results provide insight toward the mechanisms involved in KatG-INH resistance in addition to identifying key regions in the enzyme functionality, which can be used for future drug design.

Preclinical Safety Evaluation: Acute and Repeated-Dose Toxicity of a New Intranasal Recombinant Vector Vaccine TB/FLU-04L Against Tuberculosis

BACKGROUND

Vaccination against tuberculosis is one of the most successful medical measures to reduce morbidity and mortality. The BCG vaccine has been in use for more than 100 years, but its efficacy is still controversial. New vaccine candidates may offer better protection than available BCG vaccine. In this work, we studied the acute and the repeated-dose toxicity study of a new vector vaccine TB/Flu-04L against tuberculosis.

MATERIALS AND METHODS

The study was conducted on 60 BALB/c mice and 150 Wistar rats. The vaccine was administered intranasally and intravenously for the acute toxicity study. For the repeated-dose toxicity study, rats were intranasally immunized by 6.5 log₁₀ TCID₅₀ or 7.5 log₁₀ TCID₅₀ three times with 21-day intervals. Mortality, temperature, body weight, food and water consumption, hematological and biochemical parameters, urine analysis, as well as cardiovascular, respiratory, and central nervous system parameters were evaluated. A macroscopic examination of internal organs was performed.

RESULTS

The TB/FLU-04L vaccine did not cause death among the mice and rats in the acute toxicity study. There were no pathological abnormalities in animal condition, behavior, food and water consumption, temperature, and body weight during the observation period. The results suggest that intranasal repeated-dose administration of the TB/FLU-04L vaccine does not exhibit significant toxicity in rats.Hematological and biochemistry analysis and the histological examination identified no toxicity-associated changes.

CONCLUSIONS

The toxicity study in mice and rats showed that the intranasal vector vaccine TB/FLU-04L had no toxic effect. The tests confirm no adverse effects for laboratory animals in the studied parameters.

The value of multimodal ultrasonography in differential diagnosis of tuberculous and non-tuberculous superficial lymphadenitis

Background

To investigate the value of multimodal ultrasonography in differentiating tuberculosis from other lymphadenopathy.

Methods

Sixty consecutive patients with superficial lymphadenopathy treated at our hospital from January 2017 to December 2018 were categorized into four types based on the color Doppler ultrasound, five types based on contrast-enhanced ultrasound, and five types based on elastography. Sensitivity and specificity were calculated of all the three imaging, including color Doppler examination, contrast-enhanced ultrasound and one individual multimodal method, for detecting lymph nodes.

Results

A total of 60 patients were included in the final analysis. Of those, Mycobacterium tuberculosis was positive in 38 patients and negative in 22 patients. Among the 38 patients who were positive for Mycobacterium tuberculosis, of which 23 had a history of pulmonary tuberculosis, accounting for 60.53% of the positive cases, and the remaining patients did not combine lesions of other organs. Among the 60 superficial lymph nodes, 63.3% presented with tuberculous lymphadenitis. The sensitivity, specificity, and accuracy of the color Doppler examination were 73.68%, 68.18%, and 71.67%, respectively. The sensitivity, specificity and accuracy of contrast-enhanced ultrasound were 89.47%, 63.64% and 80.00%, respectively. The sensitivity, specificity and accuracy of the elastography were 63.16%, 63.64% and 63.33%, respectively. The sensitivity, specificity and accuracy of one individual multimodal method were 42.11%, 95.45% and 61.67%, respectively. The sensitivity, specificity and accuracy of all modes combined were 100.00%, 27.27% and 73.33%, respectively.

Conclusion

Multimodal ultrasonography has high predictive value for the differential diagnosis of superficial tuberculous lymphadenitis.

Safety, Tolerability, and Pharmacokinetics of Telacebec (Q203), a New Antituberculosis Agent, in Healthy Subjects

Telacebec (Q203) is a potent drug candidate under clinical development for the treatment of drug-naïve and drug-resistant tuberculosis. The first-in-human randomized, placebo-controlled, double-blind, dose-escalation Phase 1A trial (Q203-TB-PI-US001) was conducted to evaluate the safety, tolerability, and pharmacokinetics of telacebec. A total of 56 normal, healthy, male and female subjects (42 active and 14 placebo) were enrolled in the study. The doses of telacebec were 10 mg (Cohort 1), 30 mg (Cohort 2), 50 mg (Cohort 3), 100 mg (Cohort 4), 200 mg (Cohort 5), 400 mg (Cohort 6), and 800 mg (Cohort 7) in a fasted state. Subjects participating in Cohort 4 were also enrolled in Cohort 8 to investigate the food effect on the pharmacokinetics of telacebec after a high-fat meal. In all subjects dosed with telacebec (10 - 800 mg), telacebec was well tolerated and did not lead to any significant or serious adverse events. Following a single oral administration of telacebec (10 - 800 mg), telacebec plasma concentration reached the maximal plasma concentration (C_max) in average 2.0 - 3.5 h and showed multi-exponential decline thereafter. The area under the plasma concentration vs. time curve (AUC) was approximately dose-proportional. A significant increase in plasma concentrations was observed in the fed condition compared with the fasted condition with the geometric mean ratio of 3.93 for C_max. Moderate delay in T_max (4.5 h) was also observed in the fed condition. These results, combined with the demonstrated activity against drug-sensitive and multidrug-resistant Mycobacterium tuberculosis, support further investigation of telacebec for the treatment of tuberculosis.

Synthesis, antitubercular, antimicrobial activities and molecular docking study of quinoline bearing dihydropyrimidines

In order to develop the antimicrobial and antitubercular agents, we have derived quinoline bearing dihydropyrimidine analogues 5a-o and structures of these compounds were determined by spectroscopic techniques. Further, we have calculated the molecular properties prediction and drug-likeness by Molinspiration property calculation toolkit and MolSoft software, respectively. The most active compound against Mycobacterium tuberculosis (5m, MIC = 0.20 µg/mL) also possessed a maximum drug-likeness model score (0.42). Compounds 5m, 5g and 5k were possessed promising antibacterial activity against tested bacterial species. Compound 5k was the only compound to have eye-catcher antifungal activity. Furthermore, the MTT cytotoxicity results on HeLa cells suggested lower cytotoxicity of biologically active compounds. Supramolecular interactions of the synthesized compounds has been assessed my means of molecular docking studies. Although all the synthesized compounds are showing preferably good interactions with their respective proteins, their binding free energies values suggest that these molecules are preferred for antitubercular activity rather than antimicrobial activity.

Impacts of a comprehensive tuberculosis control model on the quality of clinical services and the financial burden of treatment for patients with drug-resistant tuberculosis in China: a mixed-methods evaluation

Background

The China National Health Commission-Gates TB Project Phase III implemented a comprehensive TB control model including multiple interventions to address the burden of drug-resistant TB (DRTB). This study aims to evaluate the quality of DRTB clinical services and assess the financial burden of DRTB patients during the intervention period.

Methods

A mixed-methods approach was used to evaluate the effectiveness of interventions in the three project provinces: Zhejiang, Jilin and Ningxia Hui Autonomous Region. The quantitative data included de-identified DRTB registry data during 2015–2018 in project provinces from China CDC, medical records of DRTB patients registered in 2018 (n = 106) from designated hospitals, and a structured DRTB patient survey in six sample prefectures in 2019. The quality of clinical services was evaluated using seven indicators across patient screening, diagnosis and treatment. Logistic regression was conducted to explore factors associated with the extremely high financial burden. Semi-structured in-depth interviews with policymakers and focus group discussions with physicians and DRTB patients were conducted to understand the interventions implemented and their impacts.

Results

The percentage of bacterially confirmed patients taking a drug susceptibility test (DST) increased significantly between 2015 and 2018: from 57.4 to 93.6% in Zhejiang, 12.5 to 86.5% in Jilin, and 29.7 to 91.4% in Ningxia. The treatment enrollment rate among diagnosed DRTB patients also increased significantly and varied from 73 to 82% in the three provinces in 2018. Over 90% of patients in Zhejiang and Jilin and 75% in Ningxia remained in treatment by the end of the first six months’ treatment. Among all survey respondents 77.5% incurred extremely high financial burden of treatment. Qualitative results showed that interventions on promoting rapid DST technologies and patient referral were successfully implemented, but the new financing policies for reducing patients’ financial burden were not implemented as planned.

Conclusions

The quality of DRTB related clinical services has been significantly improved following the comprehensive interventions, while the financial burden of DRTB patients remains high due to the delay in implementing financing policies. Stronger political commitment and leadership are required for multi-channel financing to provide additional financial support to DRTB patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40249-021-00832-5.

Synthesis and Biological Evaluation of Novel Benzhydrylpiperazine-Coupled Nitrobenzenesulfonamide Hybrids

A series of novel benzhydryl piperazine-coupled nitrobenzenesulfonamide hybrids were synthesized with good to excellent yields. They were tested for in vitro inhibition of mycobacterial activity against the Mycobacterium tuberculosis H37Rv strain, in vitro cytotoxicity MTT (RAW 264.7cells) assay, nutrient starvation (H37Rv strain), and ability to block Cav3.2 T-type calcium channels. Novel hybrids did not inhibit T-type calcium channels, whereas they showed excellent antituberculosis (TB) activity and low cytotoxicity with a selectivity index of >30. A direct impact of the amino acid linker was not observed. Studied hybrids exhibited good inhibition activities, and the 2,4-dinitrobenzenesulfonamide group emerged as a promising scaffold for further drug design by hybridization approaches for anti-TB therapy.

Policy changes and the screening, diagnosis and treatment of drug-resistant tuberculosis patients from 2015 to 2018 in Zhejiang Province, China: a retrospective cohort study

OBJECTIVES

To examine changes in the screening, diagnosis, treatment and management of drug-resistant tuberculosis (DRTB) patients, and investigate the impacts of DRTB-related policies on patients of different demographic and socioeconomic characteristics.

DESIGN

A retrospective cohort study using registry data, plus a survey on DRTB-related policies.

SETTING

All prefecture-level Centres for Disease Control in Zhejiang Province, China.

MAIN OUTCOME MEASURES

Alongside the care cascade, we examined: (1) reported number of presumptive DRTB patients; (2) percentage of presumptive patients with drug susceptibility testing (DST) records; (3) percentage of DRTB/rifampicin-resistant (RR) patients registered; (4) percentage of RR/multidrug-resistant TB (MDRTB) patients that received anti-DRTB treatment; and (5) percentage of RR/MDRTB patients cured/completed treatment among those treated. Multivariate logistic regressions were conducted to explore the impacts of DRTB policies after adjusting for other factors.

RESULTS

The number of reported presumptive DRTB patients and the percentage with DST records largely increased during 2015-2018, and the percentage of registered patients who received anti-DRTB treatment also increased from 59.0% to 86.5%. Patients under the policies of equipping GeneXpert plus expanded criteria for DST had a higher likelihood of being registered compared with no GeneXpert (adjusted OR (aOR)=2.57, 95% CI: 1.20 to 5.51), while for treatment initiation the association was only significant when further expanding the registration criteria (aOR=2.38, 95% CI: 1.19 to 4.79). Patients with registered residence inside Zhejiang were more likely to be registered (aOR=1.96, 95% CI: 1.52 to 2.52), treated (aOR=3.83, 95% CI: 2.78 to 5.28) and complete treatment (aOR=1.92, 95% CI: 1.03 to 3.59) compared with those outside.

CONCLUSION

The policy changes on DST and registration have effectively improved DRTB case finding and care. Nevertheless, challenges remain in servicing vulnerable groups such as migrants and improving equity in the access to TB care. Future policies should provide comprehensive support for migrants to complete treatment at their current place of residence.

Identification of active molecules against Mycobacterium tuberculosis through machine learning

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb) and it has been one of the top 10 causes of death globally. Drug-resistant tuberculosis (XDR-TB), extensively resistant to the commonly used first-line drugs, has emerged as a major challenge to TB treatment. Hence, it is quite necessary to discover novel drug candidates for TB treatment. In this study, based on different types of molecular representations, four machine learning (ML) algorithms, including support vector machine, random forest (RF), extreme gradient boosting (XGBoost) and deep neural networks (DNN), were used to develop classification models to distinguish Mtb inhibitors from noninhibitors. The results demonstrate that the XGBoost model exhibits the best prediction performance. Then, two consensus strategies were employed to integrate the predictions from multiple models. The evaluation results illustrate that the consensus model by stacking the RF, XGBoost and DNN predictions offers the best predictions with area under the receiver operating characteristic curve of 0.842 and 0.942 for the 10-fold cross-validated training set and external test set, respectively. Besides, the association between the important descriptors and the bioactivities of molecules was interpreted by using the Shapley additive explanations method. Finally, an online webserver called ChemTB (http://cadd.zju.edu.cn/chemtb/) was developed, and it offers a freely available computational tool to detect potential Mtb inhibitors.

In vitro potency of 2-(((2-hydroxyphenyl)amino)methylene)-5,5-dimethylcyclohexane-1,3-dione against drug-resistant and non-replicating persisters of Mycobacterium tuberculosis

OBJECTIVES

New antituberculosis agents active against drug-resistant and non-replicating tubercle bacilli are required. We evaluated a previously identified hit, 2-(((2-hydroxyphenyl)amino)methylene)-5,5-dimethylcyclohexane-1,3-dione (PAMCHD), against several clinical Mycobacterium tuberculosis isolates, including multidrug-resistant (MDR) strains and non-replicating drug-tolerant persisters of M. tuberculosis H37Rv.

METHODS

PAMCHD's potential against drug-resistant M. tuberculosis was investigated by broth microdilution. CFU enumeration was performed to determine PAMCHD's activity against five types of dormant bacilli.

RESULTS

No significant differences in MICs of PAMCHD were observed against M. tuberculosis H37Rv (2.5-5 µg/mL) and eight drug-susceptible strains (1.25-5 µg/mL) as well as drug-resistant strains including six isoniazid (INH)-resistant (2.5-10 µg/mL), one INH + ethambutol (EMB)-resistant (5 µg/mL), one rifampicin (RIF) + EMB-resistant (5 µg/mL) and three MDR (2.5-10 µg/mL) strains. Thus, PAMCHD maintains activity against all kinds of clinical strains, especially MDR. Regarding drug-tolerant persisters, INH and RIF killed, respectively, 0.5 and 5.0 log10 CFU of non-replicating persisters developed by hypoxia and 1.5 and 2.5 log₁₀ CFU developed by nutrient starvation at 64 × of their respective MIC against actively dividing cultures. In contrast, PAMCHD sterilised persister cultures developed by hypoxia (killed 6.5 log10 CFU) or starvation (killed 7.5 log10 CFU). PAMCHD sterilised RIF-tolerant (tolerance level up to 100 µg/mL of RIF) 100-day-old static persisters at 64 × MIC, while moxifloxacin killed only 1.0 log10 CFU of these persisters at 64 × MIC.

CONCLUSION

PAMCHD offers significant potential against MDR-TB and exhibits notable potency against non-replicating drug-tolerant M. tuberculosis persisters. These findings warrant further studies of PAMCHD for further anti-TB drug development.

Pyrazoles and fused pyrimidines: Synthesis, structure elucidation, antitubercular activity and molecular docking study

BACKGROUND

Synthesis of new heterocyclic drugs in short reaction time with sufficient quantity is considered as a target for several pharmaceutical scientists. Thus, organic reactions proceeded on the surface of nano-sized catalysts to speed up the stimulation process.

OBJECTIVE

we aimed in this research to synthesize a new series of heterocyclic compounds carrying pyrazole moiety in the presence of ZnO nano-catalyst to investigate their anti-tubercular activity.

METHODS

ZnO(NPs) was used in synthesis of novel series of thienylpyrazolopyrimidines bearing arylazo group by reaction of thiophene-enaminone and the amino-arylazopyrazoles in excellent yield. On the other hand, another series of theinyl-pyrazoles was synthesized through the reaction of the same enaminone with hydrazonoyl chlorides but the usage of ZnO(NPs) failed in such reactions.

RESULTS

The proposed structures of the products and the mechanistic pathways of the reactions were assured based on the spectral data and chemical evidences. Thienylpyrazole derivatives were assessed for their activity as Mycobacterium tuberculosis inhibitor and their results revealed that two thienylpyrazole derivatives 24d & 24f showed the most significant anti-mycobacterial activity with MIC values 0.70 & 1.29 µM/mL, respectively comparing with the MIC value = 0.60 µM/mL of the standard drug Rifampicin. Furthermore, the most active thienylpyrazole derivatives were investigated for their cytotoxic impact versus normal cells WI-38 (Normal human Lung fibroblast cells) using MTT assay. These thienylpyrazole derivatives exhibited good selective index profile. Moreover, 1,3,4-trisubstituted pyrazole analogues showed good interaction with the active site of enoyl-acyl carrier protein reductase (Mt InhA) through the molecular docking studies.

CONCLUSION

We succeeded to synthesis a new series of heterocyclic compounds carrying pyrazole moiety in the presence of ZnO nano-catalyst as anti-tubercular agents.

Trends in burden of multidrug-resistant tuberculosis in countries, regions, and worldwide from 1990 to 2017: results from the Global Burden of Disease study

Background

Antituberculosis-drug resistance is an important public health issue, and its epidemiological patterns has dramatically changed in recent decades. This study aimed to estimate the trends of multidrug-resistant tuberculosis (MDR-TB), which can be used to inform health strategies.

Methods

Data were collected from the Global Burden of Disease study 2017. The estimated annual percentage changes (EAPCs) were calculated to assess the trends of MDR-TB burden at global, regional, and national level from 1990 to 2017 using the linear regression model.

Results

Globally, the age-standardized rate (ASR) of MDR-TB burden including incidence, prevalence, death and disability-adjusted life years (DALYs) had pronounced increasing trends from 1990 to 1999, with the EAPCs were 17.63 [95% confidence interval (CI): 10.77–24.92], 17.57 (95% CI 11.51–23.95), 21.21 (95% CI 15.96–26.69), and 21.90 (95% CI 16.55–27.50), respectively. Particularly, the largest increasing trends were seen in areas and countries with low and low-middle sociodemographic index (SDI). However, the trends in incidence, prevalence, death and DALYs of MDR-TB decreased globally from 2000 to 2017, with the respective EAPCs were − 1.37 (95% CI − 1.62 to − 1.12), − 1.32 (95% CI − 1.38 to − 1.26), − 3.30 (95% CI − 3.56 to − 3.04) and − 3.32 (95% CI − 3.59 to − 3.06). Decreasing trends of MDR-TB were observed in most regions and countries, particularly that of death and DALYs in Slovenia were − 18.96 (95% CI − 20.82 to − 17.06) and -19.35 (95% CI − 21.10 to − 17.55), respectively. Whereas the pronounced increasing trends of MDR-TB occurred in Papua New Guinea, Singapore, and Australia.

Conclusions

The ASR of MDR-TB showed pronounced decreasing trends from 2000 to 2017. However, the MDR-TB burden remains a substantial challenge to the TB control globally, and requires effective control strategies and healthcare systems.

Multidrug-resistant tuberculosis in children and adolescents: current strategies for prevention and treatment

INTRODUCTION

An estimated 30,000 children develop multidrug-resistant (MDR) tuberculosis (TB) each year, with only a small proportion diagnosed and treated. This field has historically been neglected due to the perception that children with MDR-TB are challenging to diagnose and treat. Diagnostic and therapeutic developments in adults have improved pediatric management, yet further pediatric-specific research and wider implementation of evidence-based practices are required.

AREAS COVERED

This review combines the most recent data with expert opinion to highlight best practice in the evaluation, diagnosis, treatment, and support of children and adolescents with MDR-TB disease. A literature search of PubMed was carried out on topics related to MDR-TB in children. This review provides practical advice on MDR-TB prevention and gives updates on new regimens and novel treatments. The review also addresses host-directed therapy, comorbid conditions, special populations, psychosocial support, and post-TB morbidity, as well as identifying outstanding research questions.

EXPERT OPINION

Increased availability of molecular diagnostics has the potential to aid with the diagnosis of MDR-TB in children. Shorter MDR-TB disease treatment regimens have made therapy safer and shorter and further developments with novel agents and repurposed drugs should lead to additional improvements. The evidence base for MDR-TB preventive therapy is increasing.

Tuberculosis in migrants - screening, surveillance and ethics

Tuberculosis (TB) is the leading infectious cause of human mortality and is responsible for nearly 2 million deaths every year. It is often regarded as a 'silent killer' because it predominantly affects the poor and marginalized, and disease outbreaks occur in 'slow motion' compared to Ebola or coronavirus 2 (COVID-19). In low incidence countries, TB is predominantly an imported disease and TB control in migrants is pivotal for countries to progress towards TB elimination in accordance with the World Health Organisations (WHO's) End TB strategy. This review provides a brief overview of the different screening approaches and surveillance processes that are in place in low TB incidence countries. It also includes a detailed discussion of the ethical issues related to TB screening of migrants in these settings and the different interests that need to be balanced. Given recognition that a holistic approach that recognizes and respects basic human rights is required to end TB, the review considers the complexities that require consideration in low-incidence countries that are aiming for TB elimination.

Interpretation of Discordant Rifampicin Susceptibility Test Results Obtained Using GeneXpert vs Phenotypic Drug Susceptibility Testing

Background

The 3-month difference in turnaround time between Xpert and conventional phenotypic drug susceptibility testing (pDST) causes patient treatment challenges when pDST rifampin (RIF) susceptibility results and earlier Xpert results disagree, resulting in unnecessary tuberculosis (TB) patient exposure to toxic second-line drugs. Here, the prevalence of discordant RIF susceptibility test results, specifically Xpert (resistant) vs pDST (susceptible) results, was determined.

Methods

Tuberculosis patients enrolled between January 2015 and June 2018 at Beijing Chest Hospital who consecutively tested positive for RIF resistance using Xpert then negative using pDST were studied. DNA sequences and minimal inhibitory concentration (MIC) results provided insights for understanding discordant results.

Results

Of 26826 patients with suggestive TB symptoms undergoing Xpert MTB/RIF testing, 728 diagnosed as RIF-resistant were evaluated. Of these, 118 (16.2%) exhibiting Xpert RIF resistance and phenotypic RIF susceptibility yielded 104 successfully subcultured isolates; of these, 86 (82.7%) harbored rpoB gene RIF resistance–determining region mutations and 18 (17.3%) did not. The Leu511Pro (25.0%) and Leu533Pro (17.3%) mutations were most frequently associated with discordant RIF susceptibility test results. Of the 86 isolates with rpoB mutations, 42 (48.8%) with MICs ≤1.0 mg/L were assigned to the RIF-susceptible group, with Leu511Pro being the most common mutation observed. Isolates with a very low bacterial load were most frequently misdiagnosed as RIF-resistant by Xpert.

Conclusions

Approximately one-sixth of RIF-resistant TB isolates identified via Xpert yielded discordant pDST results due to questionable interpretation of specific “disputed” mutations. Thus, a diagnostic flowchart should be used to correctly interpret Xpert RIF resistance results to best guide patient treatment.

Tapping private health sector for public health program? Findings of a novel intervention to tackle TB in Mumbai, India

BACKGROUND

India carries one-fourth of the global tuberculosis (TB) burden. Hence the country has drafted the ambitious National Strategic Plan to eliminate tuberculosis by 2025. To realise this goal, India's Revised National Tuberculosis Control Programme (RNTCP) and partners piloted a novel strategy to engage private-providers for tuberculosis care via a "Private-provider Interface Agency" (PPIA) in Mumbai and other locations.

INTERVENTION

The program mapped and engaged private-providers, chemists, and laboratories; facilitated TB notification via call centers and field staff; provided free tuberculosis diagnostic tests and anti-TB drugs using novel electronic vouchers; monitored quality of care; and supported patients to ensure anti-TB treatment adherence and completion. This report summarises the descriptive analysis of PPIA implementation data piloted in Mumbai from 2014 to 2017.

FINDINGS

The program mapped 8789 private doctors, 3438 chemists, and 985 laboratories. Of these, 3836 (44%) doctors, 285 (29%) laboratories, and 353 (10%) chemists were prioritized and engaged in the program. Over three and a half years, the program recorded 60,366 privately-notified tuberculosis patients, of which, 24,146 (40%) were microbiologically-confirmed, 5203 (9%) were rifampicin-resistant, and 4401 (7%) were paediatric TB patients. Mumbai's annual total TB case notification rate increased from a pre-program baseline of 272 per 100,000/year in 2013 to 416 per 100,000/year in 2017. Overall, 42,300 (78%) patients completed the TB treatment, and 4979 (9%) could not be evaluated.

INTERPRETATION

The PPIA program in Mumbai demonstrated that private-providers can be effectively engaged for TB control in urban India. This program has influenced national policy and has been adapted and funded for a country-wide scale up. The model may also be considered in conditions where private-provider engagement is needed to improve access and quality of care for any area of public health.

Mobile resistome of human gut and pathogen drives anthropogenic bloom of antibiotic resistance

BACKGROUND

The impact of human activities on the environmental resistome has been documented in many studies, but there remains the controversial question of whether the increased antibiotic resistance observed in anthropogenically impacted environments is just a result of contamination by resistant fecal microbes or is mediated by indigenous environmental organisms. Here, to determine exactly how anthropogenic influences shape the environmental resistome, we resolved the microbiome, resistome, and mobilome of the planktonic microbial communities along a single river, the Han, which spans a gradient of human activities.

RESULTS

The bloom of antibiotic resistance genes (ARGs) was evident in the downstream regions and distinct successional dynamics of the river resistome occurred across the spatial continuum. We identified a number of widespread ARG sequences shared between the river, human gut, and pathogenic bacteria. These human-related ARGs were largely associated with mobile genetic elements rather than particular gut taxa and mainly responsible for anthropogenically driven bloom of the downstream river resistome. Furthermore, both sequence- and phenotype-based analyses revealed environmental relatives of clinically important proteobacteria as major carriers of these ARGs.

CONCLUSIONS

Our results demonstrate a more nuanced view of the impact of anthropogenic activities on the river resistome: fecal contamination is present and allows the transmission of ARGs to the environmental resistome, but these mobile genes rather than resistant fecal bacteria proliferate in environmental relatives of their original hosts. Video abstract.

Mycobacterium tuberculosis Drug Resistance and Transmission among Human Immunodeficiency Virus-Infected Patients in Ho Chi Minh City, Vietnam

Vietnam has a high burden of tuberculosis (TB) and multidrug-resistant (MDR) TB, but drug resistance patterns and TB transmission dynamics among TB/human immunodeficiency virus (HIV) coinfected patients are not well described. We characterized 200 Mycobacterium tuberculosis isolates from TB/HIV coinfected patients diagnosed at the main TB referral hospital in Ho Chi Minh City, Vietnam. Phenotypic drug susceptibility testing (DST) for first-line drugs, spoligotyping, and 24-locus mycobacterial interspersed repetitive unit (MIRU-24) analysis was performed on all isolates. The 24-locus mycobacterial interspersed repetitive unit clusters and MDR isolates were subjected to whole genome sequencing (WGS). Most of the TB/HIV coinfected patients were young (162/174; 93.1% aged < 45 years) males (173; 86.5% male). Beijing (98; 49.0%) and Indo-Oceanic (70; 35.0%) lineage strains were most common. Phenotypic drug resistance was detected in 84 (42.0%) isolates, of which 17 (8.5%) were MDR; three additional MDR strains were identified on WGS. Strain clustering was reduced from 84.0% with spoligotyping to 20.0% with MIRU-24 typing and to 13.5% with WGS. Whole genome sequencing identified five additional clusters, or members of clusters, not recognized by MIRU-24. In total, 13 small (two to three member) WGS clusters were identified, with less clustering among drug susceptible (2/27; 7.4%) than among drug-resistant strains (25/27; 92.6%). On phylogenetic analysis, strains from TB/HIV coinfected patients were interspersed among strains from the general community; no major clusters indicating transmission among people living with HIV were detected. Tuberculosis/HIV coinfection in Vietnam was associated with high rates of drug resistance and limited genomic evidence of ongoing M. tuberculosis transmission among HIV-infected patients.

Is rifampin resistance a reliable predictive marker of multidrug-resistant tuberculosis in China: A meta-analysis of findings

OBJECTIVES

Systematic review of multidrug-resistant tuberculosis (MDR-TB) prevalence among rifampicin (RIF)-resistant tuberculosis (RR-TB) patients in 34 provinces of China was conducted to correlate RIF resistance with concurrent isoniazid (INH) resistance.

METHODS

Database searches (PubMed, Embase, China National Knowledge Infrastructure, Chinese Scientific Journal, Wanfang), identified drug resistance surveillance studies conducted between January 1, 2000 and June 30, 2018. Of 1554 records, random-effects meta-analysis of 34 studies of adequate methodological quality yielded 108,366 TB cases for MDR-TB prevalence analysis of RR-TB cases.

RESULTS

MDR-TB prevalence among RR-TB cases varied from 57% (Xinjiang; 95% CI 47%, 67%) to 95% (Taiwan; 95% CI 92%, 98%), for a pooled national rate of 77% (95% CI 75%, 80%). Subgroup and meta-regression analyses revealed greater MDR-TB prevalence in previously treated versus new RR-TB cases (P < 0.001), with no significant differences of regional initial drug resistance rates or sampling methods. Regional MDR-TB prevalence among RR-TB cases was lowest (69%) in the Northeast Region (95% CI 65%, 73%) and highest (90%) in Hong Kong, Macao and Taiwan (95% CI 81%, 98%).

CONCLUSIONS

In China, ∼77% of RR-TB cases are MDR-TB. Thus, RIF resistance cannot effectively predict MDR-TB. Highly variable RR-TB prevalence across China warrants improved TB management.

Change in prevalence and molecular characteristics of isoniazid-resistant tuberculosis over a 10-year period in China

BACKGROUND

Isoniazid (INH) represents the cornerstone for the treatment of cases infected with Mycobacterium tuberculosis (MTB) strains. Several molecular mechanisms have been shown to be the major causes for INH resistance, while the dynamic change of mutations conferring INH resistance among MTB strains during the past decade is still unknown in China.

METHODS

In this study, we carried out a comparative analysis of the INH minimal inhibitory concentration (MIC) distribution, and investigate the dynamic change of molecular characteristics among INH-resistant MTB strains between 2005 and 2015.

RESULTS

The proportion of INH resistance (39.0%, 105/269) in 2015 was significantly higher than in 2005 (30.0%, 82/273; P = 0.03). Among 269 isolates collected in 2015, 76 (28.3%, 76/269) exhibited high-level INH-resistance (MIC≥32 mg/L), which was significantly higher than that in 2005 (20.5%, 56/273, P = 0.04). In addition, a significantly higher percentage of INH-resistant isolates carried inhA promoter mutations in 2015 (26.7%) versus that in 2005 (14.6%, P = 0.04), while no significant difference was observed in the rates of isolates containing katG mutations between 2005 (76.8%) and 2015 (70.5%, P = 0.33). Notably, the proportion of MTB isolates with inhA mutations (26.7%, 28/105) for patients who had previous exposure to protionamide (PTH) was higher than that for patients who had no previous exposure to PTH (21.4%, 6/28).

CONCLUSIONS

In conclusion, our results demonstrated that the proportion of INH-resistant MTB isolates significantly increased during the last decade, which was mainly attributed to an increase of high-level INH-resistant MTB. In addition, prior exposure to PTH may be associated with the increased frequency of INH-resistant tuberculosis strains with inhA mutations in China.

Map, know dynamics and act; a better way to engage private health sector in TB management. A report from Mumbai, India

BACKGROUND

India, world's leading Tuberculosis burden country envisions to End-TB by optimally engaging private-sector, in-spite of several unsuccessful attempts of optimal private sector engagement. Private Provider Interface Agency (PPIA), a new initiative for private-sector engagement, studied the private-sector networking and dynamics to understand the spread, typology of providers and facilities and their relations in TB case management, which was critical to design an intervention to engage private-sector. We report the observations of this exercise for a larger readership.

METHOD

ology: It is a descriptive analysis of mapping data (quantitative) and perceived factors influencing their engagement in the PPIA network (qualitative).

RESULTS

Of 7396 doctors, 2773 chemists and 747 laboratories mapped, 3776 (51%) doctors, 353 (13%) chemists and 255 (34%) laboratories were prioritized and engaged. While allopathic doctors highly varied between wards (mean ratio 48/100,000 population; range 13-131), non-allopathic doctors were more evenly distributed (mean ratio 58/100,000 population; range 36-83). The mean ratio between non-allopathic to allopathic doctors was 1.75. Return benefit, apprehension on continuity of funding and issues of working with the Government were top three concerns of private providers during engagement. Similarly, irrational business expectations, expectation of advance financing for surety and fear of getting branded as TB clinic were three top reasons for non-engagement.

CONCLUSION

A systematic study of dynamics of existing networking, typology and spread of private providers and using this information in establishing an ecosystem of referral network for TB control activities is crucial in an effort towards optimal engagement of private health providers. Understanding the factors influencing the network dynamics helped PPIA in effective engagement of private health providers in the project.

Cytokine-induced killer cell therapy as a promising adjunctive immunotherapy for multidrug-resistant pulmonary TB: a case report

In this report, we identified a multidrug-resistant tuberculosis (MDR-TB) patient who remained acid-fast bacilli culture positive despite aggressive WHO-directed therapy. Between July 2014 and February 2015, she received eight courses of cytokine-induced killer (CIK) cell-based adoptive cellular immunotherapy in combination to the second-line anti-TB treatment. This case achieved culture conversion, and experienced no relapse during 2-year follow-up under the treatment with CIK cell-based adoptive cellular immunotherapy. Our data indicate that CIK immunotherapy is a promising adjunctive therapeutic method for improving the efficacy combined with the second-line anti-TB regimens against MDR-TB. Randomized trials are warranted to confirm the efficacy and safety of adjunctive CIK therapy in patients infected with MDR-TB.

The burden of multidrug-resistant tuberculosis in children

BACKGROUND

Childhood tuberculosis (TB) has historically been neglected, although in recent years there has been increased focus on this problem. In particular, there have been two efforts to estimate the burden of pediatric multidrug-resistant TB (MDR-TB).

METHODS

We review current estimates of the global incidence of pediatric MDR-TB disease. We then combine pediatric MDR-TB treatment data from the World Health Organization and recently published case fatality ratio estimates for children with TB to produce mortality estimates for children with MDR-TB. Finally, we combine treatment data and estimates of household size and disease risk to estimate how many children could be treated for probable or confirmed MDR-TB by carrying out household contact investigations around adult MDR-TB patients.

RESULTS

Between 25 000 and 32 000 children develop MDR-TB disease annually, accounting for around 3% of all pediatric TB cases. Only 3-4% of these children are likely to receive MDR-TB treatment. We estimate that around 21% of children who develop MDR-TB disease will die. Carrying out household contact investigations around adult MDR-TB patients could find an estimated 12 times as many pediatric MDR-TB cases as are currently being identified.

DISCUSSION

The diagnosis and treatment of children with MDR-TB needs to be prioritized by TB programs.

Mycobacteria-Specific T Cells May Be Expanded From Healthy Donors and Are Near Absent in Primary Immunodeficiency Disorders

Mycobacterial Infections can be severe in patients with T-cell deficiency or phagocyte disorders, and treatment is frequently complicated by antimicrobial resistance. Restoration of T-cell immunity via stem cell transplantation facilitates control of mycobacterial infections, but presence of active infections during transplantation is associated with a higher risk of mortality. Adoptive T cell immunotherapy has been successful in targeting viruses, but has not been attempted to treat mycobacterial infections. We sought to expand and characterize mycobacterial-specific T-cells derived from healthy donors in order to determine suitability for adoptive immunotherapy. Mycobacteria-specific T-cells (MSTs) were generated from 10 healthy donors using a rapid ex vivo expansion protocol targeting five known mycobacterial target proteins (AG85B, PPE68, ESXA, ESXB, and ADK). MSTs were compared to T-cells expanded from the same donors using lysate from M. tuberculosis or purified protein derivative from M. avium (sensitin). MST expansion from seven patients with primary immunodeficiency disorders (PID) and two patients with IFN-γ autoantibodies and invasive M. avium infections. MSTs expanded from healthy donors recognized a median of 3 of 5 antigens, with production of IFN-γ, TNF, and GM-CSF in CD4⁺ T cells. Comparison of donors who received BCG vaccine (n = 6) to those who did not (n = 4) showed differential responses to PPE68 (p = 0.028) and ADK (p = 0.015) by IFN-γ ELISpot. MSTs expanded from lysate or sensitin also recognized multiple mycobacterial antigens, with a statistically significant differences noted only in the response to PPE68 (p = 0.016). MSTs expanded from patients with primary immunodeficiency (PID) and invasive mycobacterial infections showed activity against mycobacterial antigens in only two of seven subjects, whereas both patients with IFN-γ autoantibodies recognized mycobacterial antigens. Thus, MSTs can be generated from donors using a rapid expansion protocol regardless of history of BCG immunization. Most tested PID patients had no detectable T-cell immunity to mycobacteria despite history of infection. MSTs may have clinical utility for adoptive immunotherapy in T-cell deficient patients with invasive mycobacterial infections.

Tuberculosis and HIV Coinfection–the Challenge in the Prevention, Detection and Treatment of Tuberculosis

Background:

Tuberculosis (TB) is still a major public health concern world-wide. The increasing global burden of TB is linked to HIV infection. HIV-TB coinfection has also conditioned clinical aspects of the TB. Since the HIV is beginning in the 1980s, the HIV infection poses a significant challenge in global TB control.

Objective:

In this review we focused on the challenges of epidemiological and clinical feature of tuberculosis presented by the HIV coinfection.

Method:

The article consists of a summary of the most important effects presented by the HIV coinfection on epidemiological and clinical feature of tuberculosis. The article analyzes and summary the causes for these challenges.

Results:

The major challenges to strategy of TB control and clinical feature of TB-HIV coinfection are presented in this paper.

Conclusion:

HIV/TB co-infection is synergic, interactive and reciprocal with significant impact. The infection of HIV and Mtb affect each other and the breakdown the immune function in TB/HIV coinfected individual. HIV infection has changed the strategy of TB control, however HIV increases global burden of TB, the reduction in the TB incidence rate is far from sufficient. Atypically clinical manifestations in TB/HIV co-infected patients and increased MDR-TB and XDR-TB contribute to the challenges in the diagnosis and treatment. Increased complexity of managing patients requires expertise in the clinical m knowledge. The focused efforts to control HIV-related TB are of great urgency. These findings will provide insight into the prevention, detection and treatment of tuberculosis and will guide advances towards tuberculosis control.

Plasma Levels of Cytokines (IL-10, IFN-γ and TNF-α) in Multidrug Resistant Tuberculosis and Drug Responsive Tuberculosis Patients in Ghana

The emergence of multidrug-resistant tuberculosis (MDR⁻TB) and more recently, extensively drug-resistant (XDR) TB has intensified the need for studies aimed at identifying factors associated with TB drug resistance. This study determined the differences in plasma concentrations of pro-inflammatory (IFN-γ and TNF-α) and anti-inflammatory (IL-10) cytokines in MDR-TB and drug-susceptible (DS) TB patients, in addition to some socio-economic factors. Plasma levels of IL-10, IFN-γ and TNF-α were measured in 83 participants (comprising 49 MDR-TB and 34 DS-TB patients) using sandwich ELISA. Levels of the three cytokines were elevated in MDR-TB patients compared to DS-TB patients. The mean level of IL-10 (7.8 ± 3.61 ρg/mL) measured in MDR-TB cases was relatively higher than those of TNF-α and IFN-γ, and statistically significant (p = 0.0022) when compared to the level of IL-10 (4.8 ± 4.94 ρg/mL) in the DS-TB cases. There were statistically significant associations between MDR-TB and factors such as education level (X² = 9.895, p = 0.043), employment status (X² = 19.404, p = 0.001) and alcoholism (X² = 3.971, p = 0.046). This study adds to the knowledge that IFN-γ, TNF-α and IL-10 play a role in the host response to Mycobacterium tuberculosis (MTB). Alcohol intake can be considered as an important MDR-TB risk factor.

REASSURED diagnostics to inform disease control strategies, strengthen health systems and improve patient outcomes

Lack of access to quality diagnostics remains a major contributor to health burden in resource-limited settings. It has been more than 10 years since ASSURED (affordable, sensitive, specific, user-friendly, rapid, equipment-free, delivered) was coined to describe the ideal test to meet the needs of the developing world. Since its initial publication, technological innovations have led to the development of diagnostics that address the ASSURED criteria, but challenges remain. From this perspective, we assess factors contributing to the success and failure of ASSURED diagnostics, lessons learnt in the implementation of ASSURED tests over the past decade, and highlight additional conditions that should be considered in addressing point-of-care needs. With rapid advances in digital technology and mobile health (m-health), future diagnostics should incorporate these elements to give us REASSURED diagnostic systems that can inform disease control strategies in real-time, strengthen the efficiency of health care systems and improve patient outcomes.

Role of Oxidative Stress in the Pathology and Management of Human Tuberculosis

Tuberculosis (TB), caused by the bacterium Mycobacterium tuberculosis, is the leading cause of mortality worldwide due to a single infectious agent. The pathogen spreads primarily via aerosols and especially infects the alveolar macrophages in the lungs. The lung has evolved various biological mechanisms, including oxidative stress (OS) responses, to counteract TB infection. M. tuberculosis infection triggers the generation of reactive oxygen species by host phagocytic cells (primarily macrophages). The development of resistance to commonly prescribed antibiotics poses a challenge to treat TB; this commonly manifests as multidrug resistant tuberculosis (MDR-TB). OS and antioxidant defense mechanisms play key roles during TB infection and treatment. For instance, several established first-/second-line antitubercle antibiotics are administered in an inactive form and subsequently transformed into their active form by components of the OS responses of both host (nitric oxide, S-oxidation) and pathogen (catalase/peroxidase enzyme, EthA). Additionally, M. tuberculosis has developed mechanisms to survive high OS burden in the host, including the increased bacterial NADH/NAD⁺ ratio and enhanced intracellular survival (Eis) protein, peroxiredoxin, superoxide dismutases, and catalases. Here, we review the interplay between lung OS and its effects on both activation of antitubercle antibiotics and the strategies employed by M. tuberculosis that are essential for survival of both drug-susceptible and drug-resistant bacterial subtypes. We then outline potential new therapies that are based on combining standard antitubercular antibiotics with adjuvant agents that could limit the ability of M. tuberculosis to counter the host's OS response.

EXPERIENCING SYNDEMIC: DISENTANGLING THE BIOSOCIAL COMPLEXITY OF TUBERCULOSIS THROUGH QUALITATIVE RESEARCH

Tuberculosis (TB) remains a major global public health problem that has become a crisis fuelled by HIV and the increasing occurrence of antimicrobial resistance. What has been termed the biosocial nature of TB challenges effective control of the disease. Yet, biosocial interactions involved in the persistence of TB in diverse settings are difficult to systematically account for. The recently developed framework of syndemics provides a way to capture how complex health problems result from the interactions between diseases such as HIV and TB, and harmful social conditions such as unemployment, malnutrition and substance abuse. This article advances the syndemics scholarship by examining health conditions that cluster together with TB in the Russian Federation, by eliciting a set of social processes that precipitate this clustering and exacerbate health outcomes, and by analysing interactions between these health conditions and social processes. To provide an account of this complexity, the article takes a qualitative approach and draws on the perspectives and experiences of people with TB. The results demonstrate emergence of a syndemic of stress, substance abuse, TB and HIV that is sustained by poverty, occupational insecurity, marginalization and isolation. Frictions between the narrow focus of the health care system on TB and the wider syndemic processes in which the lives of many persons with TB are embedded, contribute to poorer health outcomes and increase the risks of developing drug resistance. Finally, the article argues that the large-scale and impersonal forces become embodied as individual pathology through the crucial interface of the ways in which persons experience and make sense of these forces and pathologies. Qualitative research is needed for the adequate analysis of this biosocial complexity in order to provide a solid basis for responses to TB-centred syndemics in various settings.

Direct Detection of Rifampin-Resistant Mycobacterium tuberculosis in Respiratory Specimens Using Quantamatrix Multiplexed Assay Platform (QMAP) System: A Multicenter Study in Korea

Rapid and accurate detection of rifampin-resistant Mycobacterium tuberculosis (MTB) is of primary importance for infection control and selection of anti-tuberculosis drugs. The aim of this study was to evaluate the usefulness of a newly developed multiplexed, bead-based bioassay (Quantamatrix Multiplexed Assay Platform, QMAP) for the direct detection of rifampin-resistant MTB in respiratory specimens. A total of 400 respiratory specimens collected from patients with clinically suspected tuberculosis or non-tuberculous mycobacteria (NTM) infections were tested with the culture-based conventional Mycobacterium species identification and QMAP system. Among 400 specimens, 154 samples were evaluated using phenotypic anti-tuberculosis drug susceptibility test (DST) and the QMAP system for the detection of rifampin resistance. Detection agreement rate between the culture-based conventional identification and QMAP system for MTB and NTM according to acid-fast bacillus smear positivity was as follows: 97.0% (131/135) and 93.6% (88/94) in 229 smear-positive samples and 69.4% (25/36) and 73.0% (65/89) in 171 smear-negative samples. Based on culture as the gold standard, the overall sensitivity and specificity of the QMAP system for Mycobacterium identification were 87.3 and 97.8%, respectively. The categorical agreement rate between phenotypic DST and QMAP system for rifampin was as follows: complete agreement, 92.9% (143/154); very major error, 0%; and major error, 0.6% (1/154). The overall sensitivity of the QMAP system for the detection of rifampin resistance was 97.1% (34/35). The QMAP system is a useful screening method for the early diagnosis of tuberculosis and selection of anti-tuberculosis drug, as it may detect rifampin-resistant MTB directly from respiratory specimens.

A complete high-quality MinION nanopore assembly of an extensively drug-resistant Mycobacterium tuberculosis Beijing lineage strain identifies novel variation in repetitive PE/PPE gene regions

A better understanding of the genomic changes that facilitate the emergence and spread of drug-resistant Mycobacterium tuberculosis strains is currently required. Here, we report the use of the MinION nanopore sequencer (Oxford Nanopore Technologies) to sequence and assemble an extensively drug-resistant (XDR) isolate, which is part of a modern Beijing sub-lineage strain, prevalent in Western Province, Papua New Guinea. Using 238-fold coverage obtained from a single flow-cell, de novo assembly of nanopore reads resulted into one contiguous assembly with 99.92 % assembly accuracy. Incorporation of complementary short read sequences (Illumina) as part of consensus error correction resulted in a 4 404 064 bp genome with 99.98 % assembly accuracy. This assembly had an average nucleotide identity of 99.7 % relative to the reference genome, H37Rv. We assembled nearly all GC-rich repetitive PE/PPE family genes (166/168) and identified variants within these genes. With an estimated genotypic error rate of 5.3 % from MinION data, we demonstrated identification of variants to include the conventional drug resistance mutations, and those that contribute to the resistance phenotype (efflux pumps/transporter) and virulence. Reference-based alignment of the assembly allowed detection of deletions and insertions. MinION sequencing provided a fully annotated assembly of a transmissible XDR strain from an endemic setting and showed its utility to provide further understanding of genomic processes within Mycobacterium tuberculosis.

Better than a pound of cure: preventing the development of multidrug-resistant tuberculosis

Diagnostic and treatment delays contribute to increased death and disability among the 490,000 adults and children who develop multidrug-resistant (MDR) tuberculosis every year. Since the treatment of MDR tuberculosis is complex, costly and often toxic, tuberculosis control programs should prioritize strategies to prevent drug-resistant tuberculosis. Opportunities to limit transmission and prevent disease progression in close contacts of MDR tuberculosis cases are often neglected. Effective MDR tuberculosis preventive strategies could minimize the costs for patients and healthcare systems. This review characterizes the biological basis for the development of MDR tuberculosis, outlines the evidence for strategies to reduce transmission and highlights programmatic approaches to the management of patients infected with drug-resistant strains of Mycobacterium tuberculosis.

Isoniazid-resistant tuberculosis: a cause for concern?

The drug isoniazid (INH) is a key component of global tuberculosis (TB) control programmes. It is estimated, however, that 16.1% of TB disease cases in the former Soviet Union countries and 7.5% of cases outside of these settings have non-multidrug-resistant (MDR) INH resistance. Resistance has been linked to poorer treatment outcomes, post-treatment relapse and death, at least for specific sites of disease. Multiple genetic loci are associated with phenotypic resistance; however, the relationship between genotype and phenotype is complex, and restricts the use of rapid sequencing techniques as part of the diagnostic process to determine the most appropriate treatment regimens for patients. The burden of resistance also influences the usefulness of INH preventive therapy. Despite seven decades of INH use, our knowledge in key areas such as the epidemiology of resistant strains, their clinical consequences, whether tailored treatment regimens are required and the role of INH resistance in fuelling the MDR-TB epidemic is limited. The importance of non-MDR INH resistance needs to be re-evaluated both globally and by national TB control programmes.

Antituberculosis drug prescribing for inpatients in a national tuberculosis hospital in China, 2011-2015

OBJECTIVES

This study aimed to describe trends in antituberculosis drug prescribing for inpatients from 2011-2015 in a Chinese national tuberculosis (TB) hospital.

METHODS

This retrospective study, performed in March 2016, reviewed the medical records of all inpatients from Beijing Chest Hospital diagnosed with TB between 2011-2015. Medication used for TB treatment during the inpatient period was recorded.

RESULTS

A total of 11465 inpatients were enrolled in the study. The most frequently prescribed drug for inpatients was isoniazid (71.2%; 8164/11465), followed by ethambutol (67.5%; 7738/11465), pyrazinamide (59.7%; 6839/11465) and rifampicin (40.0%; 4589/11465). In addition, amikacin (16.5%; 1889/11465), levofloxacin (33.0%; 3789/11465), para-aminosalicylic acid (12.4%; 1422/11465) and clarithromycin (3.5%; 406/11465) were the most common drugs used in the treatment of inpatients for Group II, III, IV and V drugs, respectively. A significant increasing trend in prescribing was found for rifampicin, pyrazinamide, capreomycin, moxifloxacin, prothionamide, para-aminosalicylic acid, cycloserine, clofazimine and linezolid, respectively, whilst there was a significant decreasing trend in the rate of prescribing of ethambutol, amikacin, levofloxacin, amoxicillin/clavulanic acid and clarithromycin during the 5-year study period (P_trend<0.01).

CONCLUSIONS

These data demonstrate that prescription of anti-TB drugs varied greatly across clinical diagnostic categories, treatment history and drug susceptibility profiles of TB patients. The World Health Organization (WHO)-endorsed standard regimen should be more extensively employed under conditions where drug susceptibility testing is unavailable in order to guide clinicians to formulate a suitable treatment regimen for TB patients.

Drug-Resistant tuberculosis - primary transmission and management

The DOTS strategy assisted global tuberculosis (TB) control, but was unable to prevent the emergence and spread of drug-resistant strains. Genomic evidence confirms the transmission of drug-resistant Mycobacterium tuberculosis strains in many different settings, indicative of epidemic spread. These findings emphasise the need for enhanced infection control measures in health care and congregate settings. Young children in TB endemic areas are particularly vulnerable. Although advances in TB drug and vaccine development are urgently needed, improved access to currently available preventive therapy and treatment for drug resistant TB could reduce the disease burden and adverse outcomes experienced by children. We review new insights into the transmission dynamics of drug resistant TB, the estimated disease burden in children and optimal management strategies to consider.