Global control of tuberculosis: from extensively drug-resistant to untreatable tuberculosis

Phenotypic drug susceptibility testing for Mycobacterium tuberculosis variant bovis BCG in 12 hours

Drug-resistant tuberculosis (DR-TB) kills ~200,000 people every year. A contributing factor is the slow turnaround time (TAT) associated with drug susceptibility diagnostics. The prevailing gold standard for phenotypic drug susceptibility testing (pDST) takes at least two weeks. Here we show that growth-based pDST for slow-growing mycobacteria can be conducted in 12 h. We use Mycobacterium tuberculosis variant bovis Bacillus Calmette-Guérin (BCG) and Mycobacterium smegmatis as the mycobacterial pathogen models and expose them to antibiotics used in (multidrug-resistant) tuberculosis (TB) treatment regimens - i.e., rifampicin (RIF), isoniazid (INH), ethambutol (EMB), linezolid (LZD), streptomycin (STR), bedaquiline (BDQ), and levofloxacin (LFX). The bacterial growth in a microfluidic chip is tracked by time-lapse phase-contrast microscopy. A deep neural network-based segmentation algorithm is used to quantify the growth rate and to determine how the strains responded to drug treatments. Most importantly, a panel of susceptible and resistant M. bovis BCG are tested at critical concentrations for INH, RIF, STR, and LFX. The susceptible strains could be identified in less than 12 h. These findings are comparable to what we expect for pathogenic M. tuberculosis as they share 99.96% genetic identity.

Evaluating Tuberculosis and Drug Resistance in Serbia: A Ten-Year Experience from a Tertiary Center

BACKGROUND

Tuberculosis (TB) remains a leading cause of mortality worldwide, particularly in low- and middle-income countries. The rise of multidrug-resistant TB (MDR-TB) poses significant challenges to global health. This study reviews the experience of the largest pulmonology center in Serbia, a country with low MDR-TB incidence, focusing on TB prevalence, resistance detection, and treatment strategies between 2012 and 2021.

METHODS

We retrospectively analyzed a total of 1239 patients who were diagnosed and treated for TB in the period from 2012 to 2021 at University Clinical Center of Serbia.

RESULTS

Drug resistance was identified in 21 patients (1.7%), with the highest resistance to rifampicin (1.4%) and isoniazid (1.3%). Pyrazinamide and streptomycin resistance were detected in only a few cases. Patients with resistant TB were younger on average, though the difference was not statistically significant (46.4 ± 19.1 vs. 53.6 ± 18.4, p = 0.079). Prior TB history was more frequent in the resistant group, almost reaching statistical significance (4 vs. 82, p = 0.052).

CONCLUSIONS

These findings underscore the critical importance of sustained surveillance, particularly of latent and drug-resistant TB forms, in alignment with the World Health Organization's (WHO) TB control strategy to preserve Serbia's low-incidence status. Moreover, given Serbia's strategic location on a major migration route, there is an elevated risk of new TB cases emerging and potential shifts in TB-drug-resistance patterns developing in the future.

Prevalence and Genetic Profiling of Second-line Drug Resistant Tuberculosis at the Tertiary Care Center of Northern India

The emergence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant TB (XDR-TB) complicates control efforts. We investigated the prevalence and genetic patterns of pre-XDR and XDRTB, by employing second-line line probe assays (SL-LPA). This prospective cohort study was conducted at the Intermediate Reference Laboratory, from November 2023 to May 2024. We screened 1253 samples via Genxpert followed by florescence microscopy, and mutational/resistance analysis via the GenoType MTBDRplus/FL-LPA (first line-line probe assay) and MTBDRsl/SL-LPA for the mutation patterns. We identified 355 rifampicin drug-resistant TB isolates, 260 of which were smear positive samples obtained for FL-LPA and SL-LPA. Finally, 255 MDR/RR-TB patients were analyzed and 73(28.62%) patients exhibited second-line drug (SLD) resistance. Among the cases, 65(89.04%) were found to be resistant solely to fluoroquinolones (FQ), whereas 3(4.11%) were resistant only to aminoglycosides (pre-XDR TB). However, 5(6.8%) patients were resistant to both FQ and aminoglycosides (XDR-TB). We also found that males 44(60.37%) were more affected by SLD resistance than 29(39.72%) females, however SLD resistant females were younger than males (26.97 ± 14.84 vs. 35.84 ± 15.26, p = 0.016). The number of previously treated patients were significantly greater in SLD-resistance than in SLD-sensitive patients. The most common mutation in the gyrA gene was D94G, which was observed in 52(71.23%) cases, followed by A90V in 10(13.69%), D94N and D94A in 4(5.48%), whereas the rrs gene presented the rrsMUT1 (A1401G) mutation in 7(9.58%) and the rrsMUT2(G1484T) mutation in 1(1.37%) of SLD-resistant patients. The alarming rate of SLD-resistance among MDR-TB patients highlights the need for improved management strategies focused on early and accurate diagnosis of DR-TB.

Advancing against drug-resistant tuberculosis: an extensive review, novel strategies and patent landscape

Drug-resistant tuberculosis (DR-TB) represents a pressing global health issue, leading to heightened morbidity and mortality. Despite extensive research efforts, the escalation of DR-TB cases underscores the urgent need for enhanced prevention, diagnosis, and treatment strategies. This review delves deep into the molecular and genetic origins of different types of DR-TB, highlighting recent breakthroughs in detection and diagnosis, including Rapid Diagnostic Tests like Xpert Ultra, Whole Genome Sequencing, and AI-based tools along with latest viewpoints on diagnosis and treatment of DR-TB utilizing newer and repurposed drug molecules. Special emphasis is given to the pivotal role of novel drugs and discusses updated treatment regimens endorsed by governing bodies, alongside innovative personalized drug-delivery systems such as nano-carriers, along with an analysis of relevant patents in this area. All the compiled information highlights the inherent challenges of current DR-TB treatments, discussing their complexity, potential side effects, and the socioeconomic strain they impose, particularly in under-resourced regions, emphasizing the cost-effective and accessible solutions. By offering insights, this review aims to serve as a compass for researchers, healthcare practitioners, and policymakers, emphasizing the critical need for ongoing R&D to improve treatments and broaden access to crucial TB interventions.

Recent Cutting-Edge Designing Strategies for Mtb-DHFR Inhibitors as Antitubercular Agents

Tuberculosis (TB) is an obstinate and infectious disease requiring a relatively longer treatment duration than other bacterial infections. The current treatment regime is prolonged and cumbersome, with adverse effects, often leading to nonadherence. The upsurge in TB's multidrug-resistant and extensively drug-resistant strains with evolved resistance to existing drugs has compounded the problems. The last two decades witnessed unprecedented progress in developing TB drugs with better efficacy and reduced toxicity. Of late, inhibitors targeting the dihydrofolate reductase (DHFR) enzyme were being explored and developed as antitubercular drugs. A plethora of diverse molecular cores, such as pteridines, diamino heterocycles, diamino triazoles, and nontraditional cores, were developed recently as Mtb-DHFR targets. Besides the characteristic binding pockets of Mtb-DHFR, an extended hydrophilic binding pocket was also studied for intermolecular interactions with the designed compounds to assess the enzyme specificity. In this study, prominent DHFR inhibitors developed in the last two decades were reported. Key features of the designed compounds, such as the structural similarities with existing pharmacophores, interactions with binding pockets, enzyme selectivity and specificity, and percentage of inhibition, were evaluated. The authors hope the study will help streamline the pharmacological pipeline of Mtb-DHFR inhibitors and bring the investigators one step closer to success.

Structure-guided identification and characterization of potent inhibitors targeting PhoP and MtrA to combat mycobacteria

Mycobacteria are causative agents of tuberculosis (TB), which is a global health concern. Drug-resistant TB strains are rapidly emerging, thereby necessitating the urgent development of new drugs. Two-component signal transduction systems (TCSs) are signaling pathways involved in the regulation of various bacterial behaviors and responses to environmental stimuli. Applying specific inhibitors of TCSs can disrupt bacterial signaling, growth, and virulence, and can help combat drug-resistant TB. We conducted a comprehensive pharmacophore-based inhibitor screening and biochemical and biophysical examinations to identify, characterize, and validate potential inhibitors targeting the response regulators PhoP and MtrA of mycobacteria. The constructed pharmacophore model Phar-PR-n4 identified effective inhibitors of formation of the PhoP-DNA complex: ST132 (IC50 = 29 ± 1.6 µM) and ST166 (IC50 = 18 ± 1.3 µM). ST166 (KD = 18.4 ± 4.3 μM) and ST132 (KD = 14.5 ± 0.1 μM) strongly targeted PhoP in a slow-on, slow-off manner. The inhibitory potency and binding affinity of ST166 and ST132 for MtrAC were comparable to those of PhoP. Structural analyses and molecular dynamics simulations revealed that ST166 and ST132 mainly interact with the α8-helix and C-terminal β-hairpin of PhoP, with functionally essential residue hotspots for structure-based inhibitor optimization. Moreover, ST166 has in vitro antibacterial activity against Macrobacterium marinum. Thus, ST166, with its characteristic 1,2,5,6-tetrathiocane and terminal sulphonic groups, has excellent potential as a candidate for the development of novel antimicrobial agents to combat pathogenic mycobacteria.

Model for predicting drug resistance based on the clinical profile of tuberculosis patients using machine learning techniques

Tuberculosis (TB) is a disease caused by the bacterium Mycobacterium tuberculosis and despite effective treatments, still affects millions of people worldwide. The advent of new treatments has not eliminated the significant challenge of TB drug resistance. Repeated and inadequate exposure to drugs has led to the development of strains of the bacteria that are resistant to conventional treatments, making the eradication of the disease even more complex. In this context, it is essential to seek more effective approaches to fighting TB. This article proposes a model for predicting drug resistance based on the clinical profile of TB patients, using machine learning techniques. The model aims to optimize the work of health professionals directly involved with tuberculosis patients, driving the creation of new containment strategies and preventive measures, as it specifies the clinical data that has the greatest impact and identifies the individuals with the greatest predisposition to develop resistance to anti-tuberculosis drugs. The results obtained show, in one of the scenarios, a probability of development of 70% and an accuracy of 84.65% for predicting drug resistance.

Recent advances in the treatment of tuberculosis

BACKGROUND

Tuberculosis (TB) is a global health challenge and one of the leading causes of death worldwide. In the last decade, the TB treatment landscape has dramatically changed. After long years of stagnation, new compounds entered the market (bedaquiline, delamanid, and pretomanid) and phase III clinical trials have shown promising results towards shortening duration of treatment for both drug-susceptible (Study 31/A5349, TRUNCATE-TB, and SHINE) and drug-resistant TB (STREAM, NiX-TB, ZeNix, and TB-PRACTECAL). Dose optimization of rifamycins and repurposed drugs has also brought hopes of further development of safe and effective regimens. Consequently, international and WHO clinical guidelines have been updated multiple times in the last years to keep pace with these advances.

OBJECTIVES

This narrative review aims to summarize the state-of-the-art on treatment of drug-susceptible and drug-resistant TB, as well as recent trial results and an overview of ongoing clinical trials.

SOURCES

A non-systematic literature review was conducted in PubMed and MEDLINE, focusing on the treatment of TB. Ongoing clinical trials were listed according to the authors' knowledge and completed consulting clinicaltrials.gov and other publicly available websites (www.resisttb.org/clinical-trials-progress-report, www.newtbdrugs.org/pipeline/trials).

CONTENT

This review summarizes the recent, major changes in the landscape for drug-susceptible and drug-resistant treatment, with a specific focus on their potential impact on patient outcomes and programmatic TB management. Moreover, insights in host-directed therapies, and advances in pharmacokinetics and pharmacogenomics are discussed. A thorough outline of ongoing therapeutic clinical trials is presented, highlighting different approaches and goals in current TB clinical research.

IMPLICATIONS

Future research should be directed to individualize regimens and protect these recent breakthroughs by preventing and identifying the selection of drug resistance and providing widespread, affordable, patient-centred access to new treatment options for all people affected by TB.

Particulate matter deposition and its impact on tuberculosis severity: A cross-sectional study in Taipei

The objective of this study was to examine the association between the lung lobe-deposited dose of inhaled fine particulate matter (PM2.5) and chest X-ray abnormalities in different lung lobes of pulmonary tuberculosis (TB), multidrug-resistant tuberculosis (MDR-TB), and non-tuberculosis mycobacteria infections (NTM). A cross-sectional study was conducted between 2014 and 2022, comprising 1073 patients who were recruited from chest department clinic in a tertial refer hospital in Taipei City, Taiwan. Ambient 1-, 7-, and 30-day PM2.5 exposure and the deposition of PM2.5 in different lung lobes were estimated in each subject. The β coefficient for PM2.5 and deposited PM2.5 in lungs with the outcome variables (pulmonary TB, MDR-TB, and NTM infection) was derived through regression analysis and adjusted for age, gender, BMI, smoking status, and family income. We observed that a 1 μg/m3 increase in ambient PM2.5 was associated with an increase of MDR-TB infections of 0.004 times (95%CI: 0.001-0.007). A 1 μg/m3 increase in 1-day and 7-day PM2.5 deposition in left upper lobe and left lower lobe was associated with an increase in chest X-ray abnormalities of 9.19 % and 1.18 % (95%CI: 0.87-17.51 and 95%CI: 0.08-2.28), and 4.52 % and 5.20 % (95%CI: 0.66-8.38 and 95%CI: 0.51-9.89) in left lung of TB patients, respectively. A 1 μg/m3 increase in 30-day PM2.5 deposition in alveolar region was associated with an increase in percent abnormality of 2.50 % (95%CI: 0.65-4.35) in left upper lobe and 3.33 % (95%CI: 0.65-6.01) in right middle lobe, while in total lung was 0.63 % (95%CI: 0.01-1.27) in right upper lobe and 0.37 % (95%CI, 0.06-0.81) in right lung of MDR-TB patients. Inhaled PM2.5 deposition in lungs was associated with an exacerbation of the radiographic severity of pulmonary TB, particularly in pulmonary MDR-TB patients in upper and middle lobes. Particulate air pollution may potentially exacerbate the radiographic severity and treatment resistance in individuals with pulmonary TB.

Indole Propionic Acid Disturbs the Normal Function of Tryptophanyl-tRNA Synthetase in Mycobacterium tuberculosis

Tuberculosis (TB) is the leading infectious disease caused by Mycobacterium tuberculosis and the second-most contagious killer after COVID-19. The emergence of drug-resistant TB has caused a great need to identify and develop new anti-TB drugs with novel targets. Indole propionic acid (IPA), a structural analog of tryptophan (Trp), is active against M. tuberculosis in vitro and in vivo. It has been verified that IPA exerts its antimicrobial effect by mimicking Trp as an allosteric inhibitor of TrpE, which is the first enzyme in the Trp synthesis pathway of M. tuberculosis. However, other Trp structural analogs, such as indolmycin, also target tryptophanyl-tRNA synthetase (TrpRS), which has two functions in bacteria: synthesis of tryptophanyl-AMP by catalyzing ATP + Trp and producing Trp-tRNATrp by transferring Trp to tRNATrp. So, we speculate that IPA may also target TrpRS. In this study, we found that IPA can dock into the Trp binding pocket of M. tuberculosis TrpRS (TrpRSMtb), which was further confirmed by isothermal titration calorimetry (ITC) assay. The biochemical analysis proved that TrpRS can catalyze the reaction between IPA and ATP to generate pyrophosphate (PPi) without Trp as a substrate. Overexpression of wild-type trpS in M. tuberculosis increased the MIC of IPA to 32-fold, and knock-down trpS in Mycolicibacterium smegmatis made it more sensitive to IPA. The supplementation of Trp in the medium abrogated the inhibition of M. tuberculosis by IPA. We demonstrated that IPA can interfere with the function of TrpRS by mimicking Trp, thereby impeding protein synthesis and exerting its anti-TB effect.

Global burden of MDR-TB and XDR-TB attributable to high fasting plasma glucose from 1990 to 2019: a retrospective analysis based on the global burden of disease study 2019

PURPOSE

High fasting plasma glucose (HFPG) has been identified as a risk factor for drug-resistant tuberculosis incidence and mortality. However, the epidemic characteristics of HFPG-attributable multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) remain unclear. We aimed to analyze the global spatial patterns and temporal trends of HFPG-attributable MDR-TB and XDR-TB from 1990 to 2019.

METHODS

Utilizing data from the Global Burden of Disease 2019 project, annual deaths and disability-adjusted life years (DALYs) of HFPG-attributable MDR-TB and XDR-TB were conducted from 1990 to 2019. Joinpoint regression was employed to quantify trends over time.

RESULTS

From 1990 to 2019, the deaths and DALYs due to HFPG-attributable MDR-TB and XDR-TB globally showed an overall increasing trend, with a significant increase until 2003 to 2004, followed by a gradual decline or stability thereafter. The low sociodemographic index (SDI) region experienced the most significant increase over the past 30 years. Regionally, Sub-Saharan Africa, Central Asia and Oceania remained the highest burden. Furthermore, there was a sex and age disparity in the burden of HFPG-attributable MDR-TB and XDR-TB, with young males in the 25-34 age group experiencing higher mortality, DALYs burden and a faster increasing trend than females. Interestingly, an increasing trend followed by a stable or decreasing pattern was observed in the ASMR and ASDR of HFPG-attributable MDR-TB and XDR-TB with SDI increasing.

CONCLUSION

The burden of HFPG-attributable MDR-TB and XDR-TB rose worldwide from 1990 to 2019. These findings emphasize the importance of routine bi-directional screening and integrated management for drug-resistant TB and diabetes.

An intramolecular cross-talk in D29 mycobacteriophage endolysin governs the lytic cycle and phage-host population dynamics

D29 mycobacteriophage encodes LysA endolysin, which mediates mycobacterial host cell lysis by targeting its peptidoglycan layer, thus projecting itself as a potential therapeutic. However, the regulatory mechanism of LysA during the phage lytic cycle remains ill defined. Here, we show that during D29 lytic cycle, structural and functional regulation of LysA not only orchestrates host cell lysis but also is critical for maintaining phage-host population dynamics by governing various phases of lytic cycle. We report that LysA exists in two conformations, of which only one is active, and the protein undergoes a host peptidoglycan-dependent conformational switch to become active for carrying out endogenous host cell lysis. D29 maintains a pool of inactive LysA, allowing complete assembly of phage progeny, thus helping avoid premature host lysis. In addition, we show that the switch reverses after lysis, thus preventing exogenous targeting of bystanders, which otherwise negatively affects phage propagation in the environment.

In vitro optimization of crushed drug-sensitive antituberculosis medication when administered via a nasogastric tube

IMPORTANCE

The incidence of tuberculosis (TB) in intensive care units (ICUs) can be as high as 3% in high-burden settings, translating to more than 7,500 patients admitted to the ICU annually. In resource-limited settings, the lack or absence of intravenous formulations of drug-sensitive antituberculosis medications necessitates healthcare practitioners to crush, dissolve, and administer the drugs to critically ill patients via a nasogastric tube (NGT). This off-label practice has been linked to plasma concentrations below the recommended target concentrations, particularly of rifampicin and isoniazid, leading to clinical failure and the development of drug resistance. Optimizing the delivery of crushed drug-sensitive antituberculosis medication via the NGT to critically ill patients is of utmost importance.

Micro-nanoemulsion and nanoparticle-assisted drug delivery against drug-resistant tuberculosis: recent developments

Tuberculosis (TB) is a major global health problem and the second most prevalent infectious killer after COVID-19. It is caused by Mycobacterium tuberculosis (Mtb) and has become increasingly challenging to treat due to drug resistance. The World Health Organization declared TB a global health emergency in 1993. Drug resistance in TB is driven by mutations in the bacterial genome that can be influenced by prolonged drug exposure and poor patient adherence. The development of drug-resistant forms of TB, such as multidrug resistant, extensively drug resistant, and totally drug resistant, poses significant therapeutic challenges. Researchers are exploring new drugs and novel drug delivery systems, such as nanotechnology-based therapies, to combat drug resistance. Nanodrug delivery offers targeted and precise drug delivery, improves treatment efficacy, and reduces adverse effects. Along with nanoscale drug delivery, a new generation of antibiotics with potent therapeutic efficacy, drug repurposing, and new treatment regimens (combinations) that can tackle the problem of drug resistance in a shorter duration could be promising therapies in clinical settings. However, the clinical translation of nanomedicines faces challenges such as safety, large-scale production, regulatory frameworks, and intellectual property issues. In this review, we present the current status, most recent findings, challenges, and limiting barriers to the use of emulsions and nanoparticles against drug-resistant TB.

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.

Evaluating pediatric tuberculosis dosing guidelines: A model-based individual data pooled analysis

BACKGROUND

The current World Health Organization (WHO) pediatric tuberculosis dosing guidelines lead to suboptimal drug exposures. Identifying factors altering the exposure of these drugs in children is essential for dose optimization. Pediatric pharmacokinetic studies are usually small, leading to high variability and uncertainty in pharmacokinetic results between studies. We pooled data from large pharmacokinetic studies to identify key covariates influencing drug exposure to optimize tuberculosis dosing in children.

METHODS AND FINDINGS

We used nonlinear mixed-effects modeling to characterize the pharmacokinetics of rifampicin, isoniazid, and pyrazinamide, and investigated the association of human immunodeficiency virus (HIV), antiretroviral therapy (ART), drug formulation, age, and body size with their pharmacokinetics. Data from 387 children from South Africa, Zambia, Malawi, and India were available for analysis; 47% were female and 39% living with HIV (95% on ART). Median (range) age was 2.2 (0.2 to 15.0) years and weight 10.9 (3.2 to 59.3) kg. Body size (allometry) was used to scale clearance and volume of distribution of all 3 drugs. Age affected the bioavailability of rifampicin and isoniazid; at birth, children had 48.9% (95% confidence interval (CI) [36.0%, 61.8%]; p < 0.001) and 64.5% (95% CI [52.1%, 78.9%]; p < 0.001) of adult rifampicin and isoniazid bioavailability, respectively, and reached full adult bioavailability after 2 years of age for both drugs. Age also affected the clearance of all drugs (maturation), children reached 50% adult drug clearing capacity at around 3 months after birth and neared full maturation around 3 years of age. While HIV per se did not affect the pharmacokinetics of first-line tuberculosis drugs, rifampicin clearance was 22% lower (95% CI [13%, 28%]; p < 0.001) and pyrazinamide clearance was 49% higher (95% CI [39%, 57%]; p < 0.001) in children on lopinavir/ritonavir; isoniazid bioavailability was reduced by 39% (95% CI [32%, 45%]; p < 0.001) when simultaneously coadministered with lopinavir/ritonavir and was 37% lower (95% CI [22%, 52%]; p < 0.001) in children on efavirenz. Simulations of 2010 WHO-recommended pediatric tuberculosis doses revealed that, compared to adult values, rifampicin exposures are lower in most children, except those younger than 3 months, who experience relatively higher exposure for all drugs, due to immature clearance. Increasing the rifampicin doses in children older than 3 months by 75 mg for children weighing <25 kg and 150 mg for children weighing >25 kg could improve rifampicin exposures. Our analysis was limited by the differences in availability of covariates among the pooled studies.

CONCLUSIONS

Children older than 3 months have lower rifampicin exposures than adults and increasing their dose by 75 or 150 mg could improve therapy. Altered exposures in children with HIV is most likely caused by concomitant ART and not HIV per se. The importance of the drug-drug interactions with lopinavir/ritonavir and efavirenz should be evaluated further and considered in future dosing guidance.

TRIAL REGISTRATION

ClinicalTrials.gov registration numbers; NCT02348177, NCT01637558, ISRCTN63579542.

Therapeutic Liquid Eutectic Solvents in Lipid Nanoparticles as Drug Vehicles-A Proof of Concept

Tuberculosis is an infectious disease caused by the bacterial complex Mycobacterium tuberculosis. Despite the decline in the incidence and mortality of this disease over the years, the emergence of new strains of tuberculosis resistant to existing tuberculostatic drugs is currently one of the largest public health problems. The engineering and development of new drugs is a complex process; therefore, the modification and enhancement of the drugs already marked is a better and faster solution. Ethambutol (ETB) is an antimycobacterial drug used to treat tuberculosis; however, it is highly hygroscopic and is sparingly soluble in water. Therapeutic Deep Eutectic Solvents (THEDESs) are known to improve drug solubility, permeability, and hygroscopicity, among others. In this study, three THEDESs of ETB were synthesized with sucralose, glucose and glycerol and then encapsulated in nanostructured lipid carriers to improve their stability. This work is a proof of concept on the possibility of encapsulating the THEDESs, and results show that the encapsulation of ETB is possible, yielding formulations with a loading capacity superior to 8.5% and able to incorporate THEDESs and not just ETB.

Trends in pulmonary tuberculosis mortality between 1985 and 2018: an observational analysis

BACKGROUND

Pulmonary tuberculosis (TB) is a major source of global morbidity and mortality. Latent infection has enabled it to spread to a quarter of the world's population. The late 1980s and early 1990s saw an increase in the number of TB cases related to the HIV epidemic, and the spread of multidrug-resistant TB. Few studies have reported pulmonary TB mortality trends. Our study reports and compares trends in pulmonary TB mortality.

METHODS

We utilized the World Health Organization (WHO) mortality database from 1985 through 2018 to analyze TB mortality using the International Classification of Diseases-10 codes. Based on the availability and quality of data, we investigated 33 countries including two countries from the Americas; 28 countries from Europe; and 3 countries from the Western Pacific region. Mortality rates were dichotomized by sex. We computed age-standardized death rates per 100,000 population using the world standard population. Time trends were investigated using joinpoint regression analysis.

RESULTS

We observed a uniform decrease in mortality in all countries across the study period except the Republic of Moldova, which showed an increase in female mortality (+ 0.12 per 100,000 population). Among all countries, Lithuania had the greatest reduction in male mortality (-12) between 1993-2018, and Hungary had the greatest reduction in female mortality (-1.57) between 1985-2017. For males, Slovenia had the most rapid recent declining trend with an estimated annual percentage change (EAPC) of -47% (2003-2016), whereas Croatia showed the fastest increase (EAPC, + 25.0% [2015-2017]). For females, New Zealand had the most rapid declining trend (EAPC, -47.2% [1985-2015]), whereas Croatia showed a rapid increase (EAPC, + 24.9% [2014-2017]).

CONCLUSIONS

Pulmonary TB mortality is disproportionately higher among Central and Eastern European countries. This communicable disease cannot be eliminated from any one region without a global approach. Priority action areas include ensuring early diagnosis and successful treatment to the most vulnerable groups such as people of foreign origin from countries with a high burden of TB and incarcerated population. Incomplete reporting of TB-related epidemiological data to WHO excluded high-burden countries and limited our study to 33 countries only. Improvement in reporting is crucial to accurately identify changes in epidemiology, the effect of new treatments, and management approaches.

Harnessing Innate Immunity to Treat Mycobacterium tuberculosis Infections: Heat-Killed Caulobacter crescentus as a Novel Biotherapeutic

Tuberculosis, caused by Mycobacterium tuberculosis (Mtb), is a serious and devastating infectious disease worldwide. Approximately a quarter of the world population harbors latent Mtb infection without pathological consequences. Exposure of immunocompetent healthy individuals with Mtb does not result in active disease in more than 90% individuals, suggesting a defining role of host immunity to prevent and/or clear early infection. However, innate immune stimulation strategies have been relatively underexplored for the treatment of tuberculosis. In this study, we used cell culture and mouse models to examine the role of a heat-killed form of a non-pathogenic microbe, Caulobacter crescentus (HKCC), in inducing innate immunity and limiting Mtb infection. We also examined the added benefits of a distinct chemo-immunotherapeutic strategy that incorporates concurrent treatments with low doses of a first-line drug isoniazid and HKCC. This therapeutic approach resulted in highly significant reductions in disseminated Mtb in the lungs, liver, and spleen of mice compared to either agent alone. Our studies demonstrate the potential of a novel innate immunotherapeutic strategy with or without antimycobacterial drugs in controlling Mtb infection in mice and open new avenues for the treatment of tuberculosis in humans.

A five-year review of prevalence and treatment outcomes of pre-extensively drug-resistant plus additional drug-resistant tuberculosis in the Henan Provincial Tuberculosis Clinical Medicine Research Centre

OBJECTIVES

This study investigated the prevalence and significant clinical outcomes of pre-extensively drug-resistant plus additional drug-resistant tuberculosis (pre-XDR-plus) in Henan Provincial Chest Hospital between 2017 and 2021.

METHODS

We analysed and summarized the drug sensitivity test (DST) results of clinical Mycobacterium tuberculosis (MTB) strains in TB patients seeking care in the Tuberculosis Clinical Medical Research Centre of Henan Province between 2017 and 2021. Medical records of pre-extensively drug-resistant plus additional drug-resistant TB patients were statistically analysed, including demographic characteristics, regimens, and outcomes.

RESULTS

Of the 3689 Mycobacterium tuberculosis strains, 639 (17.32%), 353 (9.56%), and 109 (2.95%), multidrug-resistant tuberculosis (MDR-TB), pre-extensively drug-resistant tuberculosis (pre-XDR), and pre-XDR-plus, respectively. The proportion of MDR decreased from 19.1% in 2017 to 17.5% in 2021 (χ² = 0.686, P = 0.407), the proportion of pre-XDR from 11.4% in 2017 to 9.0% in 2021 (χ² = 2.39, P = 0.122), and pre-XDR-plus from 4.7% in 2017 to 1.8% in 2020, with the declining trend was significant (χ² = 9.348, P = 0.002). The most commonly used anti-TB drugs were pyrazinamide (PZA, 37/46, 80.43%) and cycloserine (CS, 32/46, 69.57%), followed by linezolid (LZD, 25/46, 54.35%), protionamide (TH, 25/46, 54.35%), and para-aminosalicylic acid (PAS, 23/46, 50.00%). Patients receiving the LZD regimen were 5 times more likely to have a favourable outcome than those not receiving LZD (OR = 6.421, 95% CI 2.101-19.625, P = 0.001). Patients receiving a regimen containing CS were 4 times more likely to have a favourable outcome compared to those not taking CS (OR = 5.444, 95% CI 1.650-17.926, P = 0.005).

CONCLUSIONS

Our data suggest that the population of pre-XDR-plus had significantly decreased over the past five years in the Henan Provincial Chest Hospital. The COVID-19 and flood disaster affect TB patients' selection of medical services. In addition, the pre-XDR-plus patients whose regimens contain LZD or CS were more likely to have favourable outcomes.

Regional distribution of Mycobacterium tuberculosis infection and resistance to rifampicin and isoniazid as determined by high-resolution melt analysis

Background

Identifying the transmission mode and resistance mechanism of Mycobacterium tuberculosis (MTB) is key to prevent disease transmission. However, there is a lack of regional data. Therefore, the aim of this study was to identify risk factors associated with the transmission of MTB and regional patterns of resistance to isoniazid (INH) and rifampicin (RFP), as well as the prevalence of multidrug-resistant tuberculosis (MDR-TB).

Methods

High-resolution melt (HRM) analysis was conducted using sputum, alveolar lavage fluid, and pleural fluid samples collected from 17,515 patients with suspected or confirmed MTB infection in the downtown area and nine counties of Luoyang City from 2019 to 2021.

Results

Of the 17,515 patients, 82.6% resided in rural areas, and 96.0% appeared for an initial screening. The HRM positivity rate was 16.8%, with a higher rate in males than females (18.0% vs. 14.1%, p < 0.001). As expected, a positive sputum smear was correlated with a positive result for HRM analysis. By age, the highest rates of MTB infection occurred in males (22.9%) aged 26–30 years and females (28.1%) aged 21–25. The rates of resistance to RFP and INH and the incidence of MDR were higher in males than females (20.5% vs. 16.1%, p < 0.001, 15.9% vs. 12.0%, p < 0.001 and 12.9% vs. 10.2%, p < 0.001, respectively). The HRM positivity rate was much higher in previously treated patients than those newly diagnosed for MTB infection. Notably, males at the initial screening had significantly higher rates of HRM positive, INH resistance, RFP resistance, and MDR-TB than females (all, p < 0.05), but not those previously treated for MTB infection. The HRM positivity and drug resistance rates were much higher in the urban vs. rural population. By multivariate analyses, previous treatment, age < 51 years, residing in an urban area, and male sex were significantly and positively associated with drug resistance after adjusting for smear results and year of testing.

Conclusion

Males were at higher risks for MTB infection and drug resistance, while a younger age was associated with MTB infection, resistance to INH and RFP, and MDR-TB. Further comprehensive monitoring of resistance patterns is needed to control the spread of MTB infection and manage drug resistance locally.

Synthesis and Biological Evaluation of Aurachin D Analogues as Inhibitors of Mycobacterium tuberculosis Cytochrome bd Oxidase

A revised total synthesis of aurachin D (1a), an isoprenoid quinolone alkaloid that targets Mycobacterium tuberculosis (Mtb) cytochrome bd (cyt-bd) oxidase, was accomplished using an oxazoline ring-opening reaction. The ring opening enabled access to a range of electron-poor analogues, while electron-rich analogues could be prepared using the Conrad-Limpach reaction. The aryl-substituted and side-chain-modified aurachin D analogues were screened for inhibition of Mtb cyt-bd oxidase and growth inhibition of Mtb. Nanomolar inhibition of Mtb cyt-bd oxidase was observed for the shorter-chain analogue 1d (citronellyl side chain) and the aryl-substituted analogues 1g/1k (fluoro substituent at C6/C7), 1t/1v (hydroxy substituent at C5/C6) and 1u/1w/1x (methoxy substituent at C5/C6/C7). Aurachin D and the analogues did not inhibit growth of nonpathogenic Mycobacterium smegmatis, but the citronellyl (1d) and 6-fluoro-substituted (1g) inhibitors from the Mtb cyt-bd oxidase assay displayed moderate growth inhibition against pathogenic Mtb (MIC = 4-8 μM).

MicroRNA-31 mediated by interferon regulatory factor 7 signaling facilitates control of Mycobacterium tuberculosis infection

Tuberculosis (TB) induced by Mycobacterium tuberculosis (M. tuberculosis) infection remains a global most deadly infectious disease. While development of more effective TB vaccines and therapeutics relies on identifications of true biomarkers designating an immune protection against M. tuberculosis infection, exact protective immune components against M. tuberculosis infection remain largely unidentified. We previously found that severe TB induced remarkable up-regulation of interferon regulatory factor 7 (IRF7) and IRF7-related gene signatures, implicating that some unknown downstream molecules in IRF7 signaling cascades may determine the M. tuberculosis infection outcomes and serve as a protective immune component against M. tuberculosis infection. Indeed, here, we observe that genetic ablation of IRF7 leads to more severe lung pathology, increased M. tuberculosis burdens, impaired differentiation of effector/memory T subsets, and extensively elevated expression of pro-inflammatory cytokines in lungs. Importantly, IRF7 is vital for sustaining expression of PD-1/PD-L1 and PD-1/PD-L1-modulated miRNA-31. Moreover, interventions of miRNA-31 expressions via administration of miRNA-31 agomir reduces lung pathology and bacilli burdens via inducing up-regulation of gene sets involved in biological processes of defense response or cellular and chemical homeostasis in lungs. Thus, this study uncovers previously unrecognized importance and mechanisms of IRF7-mediated miRNA-31 as a protective immune component against M. tuberculosis infection.

Bedaquiline-Pretomanid-Linezolid Regimens for Drug-Resistant Tuberculosis

BACKGROUND

The bedaquiline-pretomanid-linezolid regimen has been reported to have 90% efficacy against highly drug-resistant tuberculosis, but the incidence of adverse events with 1200 mg of linezolid daily has been high. The appropriate dose of linezolid and duration of treatment with this agent to minimize toxic effects while maintaining efficacy against highly drug-resistant tuberculosis are unclear.

METHODS

We enrolled participants with extensively drug-resistant (XDR) tuberculosis (i.e., resistant to rifampin, a fluoroquinolone, and an aminoglycoside), pre-XDR tuberculosis (i.e., resistant to rifampin and to either a fluoroquinolone or an aminoglycoside), or rifampin-resistant tuberculosis that was not responsive to treatment or for which a second-line regimen had been discontinued because of side effects. We randomly assigned the participants to receive bedaquiline for 26 weeks (200 mg daily for 8 weeks, then 100 mg daily for 18 weeks), pretomanid (200 mg daily for 26 weeks), and daily linezolid at a dose of 1200 mg for 26 weeks or 9 weeks or 600 mg for 26 weeks or 9 weeks. The primary end point in the modified intention-to-treat population was the incidence of an unfavorable outcome, defined as treatment failure or disease relapse (clinical or bacteriologic) at 26 weeks after completion of treatment. Safety was also evaluated.

RESULTS

A total of 181 participants were enrolled, 88% of whom had XDR or pre-XDR tuberculosis. Among participants who received bedaquiline-pretomanid-linezolid with linezolid at a dose of 1200 mg for 26 weeks or 9 weeks or 600 mg for 26 weeks or 9 weeks, 93%, 89%, 91%, and 84%, respectively, had a favorable outcome; peripheral neuropathy occurred in 38%, 24%, 24%, and 13%, respectively; myelosuppression occurred in 22%, 15%, 2%, and 7%, respectively; and the linezolid dose was modified (i.e., interrupted, reduced, or discontinued) in 51%, 30%, 13%, and 13%, respectively. Optic neuropathy developed in 4 participants (9%) who had received linezolid at a dose of 1200 mg for 26 weeks; all the cases resolved. Six of the seven unfavorable microbiologic outcomes through 78 weeks of follow-up occurred in participants assigned to the 9-week linezolid groups.

CONCLUSIONS

A total of 84 to 93% of the participants across all four bedaquiline-pretomanid-linezolid treatment groups had a favorable outcome. The overall risk-benefit ratio favored the group that received the three-drug regimen with linezolid at a dose of 600 mg for 26 weeks, with a lower incidence of adverse events reported and fewer linezolid dose modifications. (Funded by the TB Alliance and others; ZeNix ClinicalTrials.gov number, NCT03086486.).

Imaging of antitubercular dimeric boronic acids at the mycobacterial cell surface by click-probe capture

Dimeric boronic acids kill Mycobacterium tuberculosis (Mtb) by targeting mycobacterial specific extracellular glycans, removing the requirement for a therapeutic agent to permeate the complex cell envelope. Here we report the successful development and use of new ‘clickable’ boronic acid probes as a powerful method to enable the direct detection and visualisation of this unique class of cell-surface targeting antitubercular agents.

Antitubercular ‘clickable’ diboronic acid agents are directly incorporated into the mycobacterial cell envelope through glycan-targeting.

Pathogenesis of SARS-CoV-2 and Mycobacterium tuberculosis Coinfection

Coronavirus disease-2019 (COVID-19), caused by SARS-CoV-2, is an infectious disease that poses severe threats to global public health and significant economic losses. The COVID-19 global burden is rapidly increasing, with over 246.53 million COVID-19 cases and 49.97 million deaths reported in the WHO 2021 report. People with compromised immunity, such as tuberculosis (TB) patients, are highly exposed to severe COVID-19. Both COVID-19 and TB diseases spread primarily through respiratory droplets from an infected person to a healthy person, which may cause pneumonia and cytokine storms, leading to severe respiratory disorders. The COVID-19-TB coinfection could be fatal, exacerbating the current COVID-19 pandemic apart from cellular immune deficiency, coagulation activation, myocardial infarction, and other organ dysfunction. This study aimed to assess the pathogenesis of SARS-CoV-2-Mycobacterium tuberculosis coinfections. We provide a brief overview of COVID19-TB coinfection and discuss SARS-CoV-2 host cellular receptors and pathogenesis. In addition, we discuss M. tuberculosis host cellular receptors and pathogenesis. Moreover, we highlight the impact of SARS-CoV-2 on TB patients and the pathological pathways that connect SARS-CoV-2 and M. tuberculosis infection. Further, we discuss the impact of BCG vaccination on SARS-CoV-2 cases coinfected with M. tuberculosis, as well as the diagnostic challenges associated with the coinfection.

Efficacy and safety of vitamin D in tuberculosis patients: a systematic review and meta-analysis

BACKGROUND

Evidence from the basic research and epidemiological studies indicates a beneficial effect of vitamin D in the treatment of tuberculosis (TB). However, the evidence from randomized controlled trials (RCTs) is inconsistent.

OBJECTIVES

This systematic review and meta-analysis was performed to synthesize evidence regarding role of vitamin D versus placebo for the management of TB.

MATERIALS AND METHODS

We searched PubMed and Cochrane Clinical Trial Registry for RCTs comparing vitamin D versus placebo for the treatment of TB. RCTs enrolling adult patients with TB receiving vitamin D in addition to standard treatment were included. Data were pooled using random effects model. The study was conducted according to PRISMA guidelines and protocol was registered with PROSPERO (CRD42016052841).

RESULTS

Of 605 identified references, 12 RCTs were included. The overall risk of bias in included studies was low or unclear. There was no significant difference between vitamin D and placebo group for any outcomes of efficacy (time to culture conversion, time to smear conversion, rate of culture conversion, and rate of smear conversion) or safety (mortality, serious adverse events, and nonserious adverse events).

CONCLUSION

Vitamin D administered with standard treatment has no beneficial effect in the TB patients as compared to the placebo.

The gut microbiota mediates protective immunity against tuberculosis via modulation of lncRNA

The gut-lung axis has been implicated as a potential therapeutic target in lung disorders. While increasing evidence suggests that gut microbiota plays a critical role in regulating host immunity and contributing to tuberculosis (TB) development and progression, the underlying mechanisms whereby gut microbiota may impact TB outcomes are not fully understood. Here, we found that broad-spectrum antibiotics treatment increased susceptibility to Mycobacterium tuberculosis (M. tuberculosis) infection and modulated pulmonary inflammatory responses in mouse M. tuberculosis infection model. We then identified a commensal gut bacteria-regulated lncRNA, termed lncRNA-CGB, which was down-regulated by dysbiosis of gut microbiota during TB infection. Furthermore, we found that Bacteroides fragilis (B. fragilis) was a direct regulator of lncRNA-CGB, and oral administration of B. fragilis enhanced expression of lncRNA-CGB and promoted anti-TB immunity. Genomic knock-out of lncRNA-CGB led to reduced IFN-γ expression and impaired anti-TB immunity, therefore leading to detrimental effects on M. tuberculosis infection. Mechanistically, lncRNA-CGB interacted with EZH2 and negatively regulated H3K27 tri-methylation (H3K27Me3) epigenetic programming, leading to enhanced IFN-γ expression. Thus, this work not only uncovered previously unrecognized importance of gut bacteria-lncRNA-EZH2-H3K27Me3 axis in conferring immune protection against TB but also identified a potential new paradigm to develop a microbiota-based treatment against TB and potentially other diseases.

Nuclease activity: an exploitable biomarker in bacterial infections

INTRODUCTION

In the increasingly challenging field of clinical microbiology, diagnosis is a cornerstone whose accuracy and timing are crucial for the successful management, therapy, and outcome of infectious diseases. Currently employed biomarkers of infectious diseases define the scope and limitations of diagnostic techniques. As such, expanding the biomarker catalog is crucial to address unmet needs and bring about novel diagnostic functionalities and applications.

AREAS COVERED

This review describes the extracellular nucleases of 15 relevant bacterial pathogens and discusses the potential use of nuclease activity as a diagnostic biomarker. Articles were searched for in PubMed using terms: "nuclease", "bacteria", "nuclease activity" or "biomarker". For overview sections, original and review articles between 2000 and 2019 were searched for using terms: "infections", "diagnosis", "bacterial", "burden", "challenges". Informative articles were selected.

EXPERT OPINION

Using the catalytic activity of nucleases offers new possibilities compared to established biomarkers. Nucleic acid activatable reporters in combination with different transduction platforms and delivery methods can be used to detect disease-associated nuclease activity patterns in vitro and in vivo for prognostic and diagnostic applications. Even when these patterns are not obvious or of unknown etiology, screening platforms could be used to identify new disease reporters.

An amiloride derivative is active against the F1Fo-ATP synthase and cytochrome bd oxidase of Mycobacterium tuberculosis

Increasing antimicrobial resistance compels the search for next-generation inhibitors with differing or multiple molecular targets. In this regard, energy conservation in Mycobacterium tuberculosis has been clinically validated as a promising new drug target for combatting drug-resistant strains of M. tuberculosis. Here, we show that HM2-16F, a 6-substituted derivative of the FDA-approved drug amiloride, is an anti-tubercular inhibitor with bactericidal properties comparable to the FDA-approved drug bedaquiline (BDQ; Sirturo^®) and inhibits the growth of bedaquiline-resistant mutants. We show that HM2-16F weakly inhibits the F₁F_o-ATP synthase, depletes ATP, and affects the entry of acetyl-CoA into the Krebs cycle. HM2-16F synergizes with the cytochrome bcc-aa₃ oxidase inhibitor Q203 (Telacebec) and co-administration with Q203 sterilizes in vitro cultures in 14 days. Synergy with Q203 occurs via direct inhibition of the cytochrome bd oxidase by HM2-16F. This study shows that amiloride derivatives represent a promising discovery platform for targeting energy generation in drug-resistant tuberculosis.

Derivatives of the FDA-approved drug, amiloride, can eliminate drug-resistant Mycobacterium tuberculosis in vitro by interfering with bacterial energy conservation.

Treatment outcomes of patients with MDR-TB and its determinants at referral hospitals in Ethiopia

BACKGROUND

There is limited empirical evidence in Ethiopia on the determinants of treatment outcomes of patients with multidrug-resistant tuberculosis (MDR-TB) who were enrolled to second-line anti-tuberculosis drugs. Thus, this study investigated the determinants of treatment outcomes in patients with MDR-TB at referral hospitals in Ethiopia.

DESIGN AND METHODS

This study was underpinned by a cross-sectional quantitative research design that guided both data collection and analysis. Data is collected using structured questionnaire and data analyses was performed using the Statistical Package for Social Sciences. Multi-variable logistic regression was used to control for confounders in determining the association between treatment outcomes of patients with MDR-TB and selected predictor variables, such as co-morbidity with MDR-TB and body mass index.

RESULTS

From the total of 136 patients with MDR-TB included in this study, 31% had some co-morbidity with MDR-TB at baseline, and 64% of the patients had a body mass index of less than 18.5 kg/m2. At 24 months after commencing treatment, 76 (69%), n = 110), of the patients had successfully completed treatment, while 30 (27%) died of the disease. The odds of death was significantly higher among patients with low body mass index (AOR = 2.734, 95% CI: 1.01-7.395; P<0.048) and those with some co-morbidity at baseline (AOR = 4.260, 95%CI: 1.607-11.29; p<0.004).

CONCLUSION

The higher proportion of mortality among patients treated for MDR-TB at Adama and Nekemte Hospitals, central Ethiopia, is attributable to co-morbidities with MDR-TB, including HIV/AIDS and malnutrition. Improving socio-economic and nutritional support and provision of integrated care for MDR-TB and HIV/AIDS is recommended to mitigate the higher level of death among patients treated for MDR-TB.

Risk Factors for Poor Outcomes Among Patients with Extensively Drug-Resistant Tuberculosis (XDR-TB): A Scoping Review

In recent years, there has been an upsurge in cases of drug-resistant TB, and strains of TB resistant to all forms of treatment have begun to emerge; the highest level of resistance is classified as extensively drug-resistant tuberculosis (XDR-TB). There is an urgent need to prevent poor outcomes (death/default/failed treatment) of XDR-TB, and knowing the risk factors can inform such efforts. The objective of this scoping review was to therefore identify risk factors for poor outcomes among XDR-TB patients. We searched three scientific databases, PubMed, Scopus, and ProQuest, and identified 25 articles that examined relevant risk factors. Across the included studies, the proportion of patients with poor outcomes ranged from 8.6 to 88.7%. We found that the most commonly reported risk factor for patients with XDR-TB developing poor outcomes was having a history of TB. Other risk factors were human immunodeficiency virus (HIV), a history of incarceration, low body mass, being a smoker, alcohol use, unemployment, being male, and being middle-aged. Knowledge and understanding of the risk factors associated with poor outcomes of XDR-TB can help policy makers and organizations in the process of designing and implementing effective programs.

A fully automatic artificial intelligence-based CT image analysis system for accurate detection, diagnosis, and quantitative severity evaluation of pulmonary tuberculosis

Objectives

An accurate and rapid diagnosis is crucial for the appropriate treatment of pulmonary tuberculosis (TB). This study aims to develop an artificial intelligence (AI)–based fully automated CT image analysis system for detection, diagnosis, and burden quantification of pulmonary TB.

Methods

From December 2007 to September 2020, 892 chest CT scans from pathogen-confirmed TB patients were retrospectively included. A deep learning–based cascading framework was connected to create a processing pipeline. For training and validation of the model, 1921 lesions were manually labeled, classified according to six categories of critical imaging features, and visually scored regarding lesion involvement as the ground truth. A “TB score” was calculated based on a network-activation map to quantitively assess the disease burden. Independent testing datasets from two additional hospitals (dataset 2, n = 99; dataset 3, n = 86) and the NIH TB Portals (n = 171) were used to externally validate the performance of the AI model.

Results

CT scans of 526 participants (mean age, 48.5 ± 16.5 years; 206 women) were analyzed. The lung lesion detection subsystem yielded a mean average precision of the validation cohort of 0.68. The overall classification accuracy of six pulmonary critical imaging findings indicative of TB of the independent datasets was 81.08–91.05%. A moderate to strong correlation was demonstrated between the AI model–quantified TB score and the radiologist-estimated CT score.

Conclusions

The proposed end-to-end AI system based on chest CT can achieve human-level diagnostic performance for early detection and optimal clinical management of patients with pulmonary TB.

Key Points

• Deep learning allows automatic detection, diagnosis, and evaluation of pulmonary tuberculosis.

• Artificial intelligence helps clinicians to assess patients with tuberculosis.

• Pulmonary tuberculosis disease activity and treatment management can be improved.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-08365-z.

Varying clinical presentations of nontuberculous mycobacterial disease : Similar to but different from tuberculosis

The incidence rate of pulmonary nontuberculous mycobacterial disease (PNTMD) in Japan is the highest among major industrialized nations. Although the typical clinical course and radiological manifestations of PNTMD are different from those of pulmonary tuberculosis (TB), confusion about these mycobacterial diseases leads to a diagnostic pitfall. Diagnostic challenges include the coexistence of Mycobacterium tuberculosis (MTB) and nontuberculous mycobacteria (NTM), false positives for NTM in MTB nucleic acid amplification tests, microbial substitution, and abnormal radiological manifestations caused by NTM. Features of extrapulmonary NTM diseases, such as pleurisy, vertebral osteomyelitis, and disseminated disease, are different from the corresponding tuberculous diseases. Moreover, the immunological background of the patient (status of human immunodeficiency virus infection with or without antiviral therapy, continuation or discontinuation of immunosuppressive therapy, use of immune checkpoint inhibitor, pregnancy and delivery, etc.) influences the pathophysiology of mycobacterial diseases. This review describes the varying clinical presentations of NTM disease with emphasis on the differences from TB. J. Med. Invest. 68 : 220-227, August, 2021.

Dihydroartemisinin-Loaded Chitosan Nanoparticles Inhibit the Rifampicin-Resistant Mycobacterium tuberculosis by Disrupting the Cell Wall

Tuberculosis (TB) caused by Mycobacterium tuberculosis (MTB) is a deadly infection, and increasing resistance worsens an already bad scenario. In this work, a new nanomedicine antibacterial agent, based on dihydroartemisinin (DHA) and chitosan (CS), has been successfully developed to overcome MTB's drug-resistant. To enhance DHA's solubility, we have prepared nanoparticles of DHA loaded CS by an ionic crosslinking method with sodium tripolyphosphate (STPP) as the crosslinking agent. The DHA-CS nanoparticles (DHA-CS NPs) have been fully characterized by scanning electron microscopy, Fourier transforms infrared spectroscopy, dynamic light scattering, and ultraviolet spectrophotometry. DHA-CS NPs show an excellent antibacterial effect on the rifampicin (RFP)-resistant strain (ATCC 35838) and, at a concentration of 8.0 μg/ml, the antibacterial impact reaches up to 61.0 ± 2.13% (n = 3). The results of Gram staining, acid-fast staining, auramine "O" staining and electron microscopy show that the cell wall of RFP-resistant strains is destroyed by DHA-CS NPs (n = 3), and it is further verified by gas chromatography-mass spectrometry. Since all the metabolites identified in DHA-CS NPs treated RFP-resistant strains indicate an increase in fatty acid synthesis and cell wall repair, it can be concluded that DHA-CS NPs act by disrupting the cell wall. In addition, the resistance of 12 strains is effectively reduced by 8.0 μg/ml DHA-CS NPs combined with RFP, with an effective rate of 66.0%. The obtained results indicate that DHA-CS NPs combined with RFP may have potential use for TB treatment.

Additional Drug Resistance in Patients with Multidrug-resistant Tuberculosis in Korea: a Multicenter Study from 2010 to 2019

BACKGROUND

Drug-resistance surveillance (DRS) data provide key information for building an effective treatment regimen in patients with multidrug-resistant tuberculosis (MDR-TB). This study was conducted to investigate the patterns and trends of additional drug resistance in MDR-TB patients in South Korea.

METHODS

Phenotypic drug susceptibility test (DST) results of MDR-TB patients collected from seven hospitals in South Korea from 2010 to 2019 were retrospectively analyzed.

RESULTS

In total, 633 patients with MDR-TB were included in the analysis. Of all patients, 361 (57.0%) were new patients. All patients had additional resistance to a median of three anti-TB drugs. The resistance rates of any fluoroquinolone (FQ), linezolid, and cycloserine were 26.2%, 0.0%, and 6.3%, respectively. The proportions of new patients and resistance rates of most anti-TB drugs did not decrease during the study period. The number of additional resistant drugs was significantly higher in FQ-resistant MDR-TB than in FQ-susceptible MDR-TB (median of 9.0 vs. 2.0). Among 26 patients with results of minimum inhibitory concentrations for bedaquiline (BDQ) and delamanid (DLM), one (3.8%) and three (11.5%) patients were considered resistant to BDQ and DLM with interim critical concentrations, respectively. Based on the DST results, 72.4% and 24.8% of patients were eligible for the World Health Organization's longer and shorter MDR-TB treatment regimen, respectively.

CONCLUSION

The proportions of new patients and rates of additional drug resistance in patients with MDR-TB were high and remain stable in South Korea. A nationwide analysis of DRS data is required to provide effective treatment for MDR-TB patients in South Korea.

Up regulated virulence genes in M. tuberculosis H37Rv gleaned from genome wide expression profiles

Identification of up regulated virulence genes in M. tuberculosis H37Rv using genome wide expression profiles is of interest in drug discovery for the disease. Hence, we report 17 up-regulated PPIN (Protein-Protein Interaction Network) enriched potential virulence linked genes using expression data available at the Gene Expression Omnibus (GEO) database for further consideration.

Elucidating the Antimycobacterial Mechanism of Action of Decoquinate Derivative RMB041 Using Metabolomics

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), still remains one of the leading causes of death from a single infectious agent worldwide. The high prevalence of this disease is mostly ascribed to the rapid development of drug resistance to the current anti-TB drugs, exacerbated by lack of patient adherence due to drug toxicity. The aforementioned highlights the urgent need for new anti-TB compounds with different antimycobacterial mechanisms of action to those currently being used. An N-alkyl quinolone; decoquinate derivative RMB041, has recently shown promising antimicrobial activity against Mtb, while also exhibiting low cytotoxicity and excellent pharmacokinetic characteristics. Its exact mechanism of action, however, is still unknown. Considering this, we used GCxGC-TOFMS and well described metabolomic approaches to analyze and compare the metabolic alterations of Mtb treated with decoquinate derivative RMB041 by comparison to non-treated Mtb controls. The most significantly altered pathways in Mtb treated with this drug include fatty acid metabolism, amino acid metabolism, glycerol metabolism, and the urea cycle. These changes support previous findings suggesting this drug acts primarily on the cell wall and secondarily on the DNA metabolism of Mtb. Additionally, we identified metabolic changes suggesting inhibition of protein synthesis and a state of dormancy.

Facile synthesis and antimycobacterial activity of isoniazid, pyrazinamide and ciprofloxacin derivatives

Several rationally designed isoniazid (INH), pyrazinamide (PZA) and ciprofloxacin (CPF) derivatives were conveniently synthesized and evaluated in vitro against H37Rv Mycobacterium tuberculosis (M. tb) strain. CPF derivative 16 displayed a modest activity (MIC = 16 µg/ml) and was docked into the M. tb DNA gyrase. Isoniazid-pyrazinoic acid (INH-POA) hybrid 21a showed the highest potency in our study (MIC = 2 µg/ml). It also retained its high activity against the other tested M. tb drug-sensitive strain (DS) V4207 (MIC = 4 µg/ml) and demonstrated negligible cytotoxicity against Vero cells (IC50  ≥ 64 µg/ml). Four tested drug-resistant (DR) M. tb strains were refractory to 21a, similar to INH, whilst being sensitive to CPF. Compound 21a was also inactive against two non-tuberculous mycobacterial (NTM) strains, suggesting its selective activity against M. tb. The noteworthy activity of 21a against DS strains and its low cytotoxicity highlight its potential to treat DS M. tb.

The Phosphatidyl-myo-Inositol Dimannoside Acyltransferase PatA Is Essential for Mycobacterium tuberculosis Growth In Vitro and In Vivo

Mycobacterium tuberculosis comprises an unusual cell envelope dominated by unique lipids and glycans that provides a permeability barrier against hydrophilic drugs and is central for its survival and virulence. Phosphatidyl-myo-inositol mannosides (PIMs) are glycolipids considered to be not only key structural components of the cell envelope but also the precursors of lipomannan (LM) and lipoarabinomannan (LAM), important lipoglycans implicated in host-pathogen interactions. Here, we focus on PatA, a membrane-associated acyltransferase that transfers a palmitoyl moiety from palmitoyl coenzyme A (palmitoyl-CoA) to the 6-position of the mannose ring linked to the 2-position of inositol in PIM₁/PIM₂ We validate that the function of PatA is vital for M. tuberculosis in vitro and in vivo We constructed a patA conditional mutant and showed that silencing patA is bactericidal in batch cultures. This phenotype was associated with significantly reduced levels of Ac₁PIM₂, an important structural component of the mycobacterial inner membrane. The requirement of PatA for viability was also demonstrated during macrophage infection and in a mouse model of infection, where a dramatic decrease in viable counts was observed upon silencing of the patA gene. This is reminiscent of the behavior of PimA, the mannosyltransferase that initiates the PIM pathway, also found to be essential for M. tuberculosis growth in vitro and in vivo Altogether, the experimental data highlight the significance of the early steps of the PIM biosynthetic pathway for M. tuberculosis physiology and reveal that PatA is a novel target for drug discovery programs against this major human pathogen.IMPORTANCE Tuberculosis (TB) is the leading cause of death from a single infectious agent. The emergence of drug resistance in strains of M. tuberculosis, the etiologic agent of TB, emphasizes the need to identify new targets and antimicrobial agents. The mycobacterial cell envelope is a major factor in this intrinsic drug resistance. Here, we have focused on the biosynthesis of PIMs, key virulence factors and important components of the cell envelope. Specifically, we have determined that PatA, the acyltransferase responsible for the first acylation step of the PIM synthesis pathway, is essential in M. tuberculosis These results highlight the importance of early steps of the PIM biosynthetic pathway for mycobacterial physiology and the suitability of PatA as a potential new drug target.

MiR-21 Is Remotely Governed by the Commensal Bacteria and Impairs Anti-TB Immunity by Down-Regulating IFN-γ

Tuberculosis (TB), which is a frequent and important infectious disease caused by Mycobacterium tuberculosis, has resulted in an extremely high burden of morbidity and mortality. The importance of intestinal dysbacteriosis in regulating host immunity has been implicated in TB, and accumulating evidence suggests that microRNAs (miRNAs) might act as a key mediator in maintaining intestinal homeostasis through signaling networks. However, the involvement of miRNA in gut microbiota, TB and the host immune system remains unknown. Here we showed that intestinal dysbacteriosis increases the susceptibility to TB and remotely increased the expression of miR-21 in lung. Systemic antagonism of miR-21 enhanced IFN-γ production and further conferred immune protection against TB. Molecular experiments further indicated that miR-21a-3p could specifically target IFN-γ mRNA. These findings revealed regulatory pathways implicating intestinal dysbacteriosis induced-susceptibility to TB: intestinal dysbiosis→lung miRNA→targeting IFN-γ→impaired anti-TB immunity. This study also suggested that deregulated miRNAs by commensal bacteria could become promising targets as TB therapeutics.

A Current Microbiological Picture of Mycobacterium Isolates from Istanbul, Turkey

Despite advances in diagnosis and treatment, tuberculosis (TB) continues to be one of the essential health problems throughout the world. Turkey is considered to be endemic for TB. In this study, we analyzed the distribution of Mycobacterium species, compare the diagnostic methods, and susceptibilities to anti-tuberculosis drugs of TB isolates. The aim was to document the current status and to provide a frame of reference for future studies. In this study, 278 Mycobacterium species isolated from 7,480 patients between September 2015 and June 2019 were included. Löwenstein-Jensen medium (LJ) and MGIT 960 were used for the isolation of strains. Susceptibility to 1^st-line anti-tuberculosis drugs was determined. Positivity rates in clinical samples were as follows: 1.4% for direct microscopic acid-fast bacilli (AFB) detection, 3.4% for growth on the LJ, and 3.7% for growth on MGIT-960. Two hundred thirty-three isolates were identified as Mycobacterium tuberculosis complex (MTBC) and 45 were non-tuberculous mycobacteria (NTMs). Eleven of the NTMs (24.4%) were Mycobacterium fortuitum group isolates, and eight NTMs (17.7%) were Mycobacterium abscessus complex isolates. A number of patients diagnosed with tuberculosis peaked twice between the ages of 20–31 and 60–71. A hundred and eighty-two MTBC isolates (78.1%) were susceptible to all 1^st-line anti-tuberculosis drugs, while 51 isolates (21.9%) were resistant to at least one drug tested. The multidrug-resistant tuberculosis rate was 13.7% among resistant strains and 3% in all strains. The liquid cultures were better for detection of both MTBC and NTMs isolates. The data demonstrate that MTBC continues to be challenge for this country and indicates the need for continued surveillance and full-spectrum services of mycobacteriology laboratory and infectious diseases.

Telacebec (Q203): Is there a novel effective and safe anti-tuberculosis drug on the horizon?

High prevalence and stronger emergency of various forms of drug-resistant tuberculosis (DR-TB), including the multidrug-resistant (MDR-TB) as well as extensively drug-resistant (XDR-TB) ones, caused by variously resistant Mycobacterium tuberculosis pathogens, make first-line anti-tuberculosis (anti-TB) agents therapeutically more and more ineffective. Therefore, there is an imperative to develop novel highly efficient (synthetic) agents against both drug-sensitive-TB and DR-TB. The exploration of various heterocycles as prospective core scaffolds for the discovery, development and optimization of anti-TB drugs remains an intriguing scientific endeavour. Telacebec (Q203; TCB), a molecule containing an imidazo[1,2-a]pyridine-3-carboxamide (IPA) structural motif, is considered a novel very promising anti-TB agent showing a unique mechanism of action. The compound blocks oxidative phosphorylation by inhibiting a mycobacterial respiratory chain due to interference with a specific cytochrome b subunit (QcrB) of transmembrane bc1 menaquinol-cytochrome c oxidoreductase as an essential component for transporting electrons across the membrane from menaquinol to other specific subunit, cytochrome c (QcrC). Thus, the ability of mycobacteria to synthesize adenosine-5´-triphosphate is limited and energy generating machinery is disabled. The TCB molecule effectively fights drug-susceptible, MDR as well as XDR M. tuberculosis strains. The article briefly explains a mechanism of an anti-TB action related to the compounds containing a variously substituted IPA scaffold and is focused on their fundamental structure-anti-TB activity relationships as well. Special consideration is paid to TCB indicating the importance of particular structural fragments for maintaining (or even improving) favourable pharmacodynamic, pharmacokinetic and/or toxicological properties. High lipophilicity of TCB might be regarded as one of the key physicochemical properties with positive impact on anti-TB effect of the drug. In January 2021, the TCB molecule was also involved in phase-II clinical trials focused on the treatment of Coronavirus Disease-19 caused by Severe Acute Respiratory Syndrome Coronavirus 2.

Prevalence and Correlates of Anxiety and Depressive Symptoms in Patients With and Without Multi-Drug Resistant Pulmonary Tuberculosis in China

China is still among the 30 high-burden tuberculosis (TB) countries in the world and TB remains a public health concern. TB can be a cause of mental illness, with prolonged treatment and several anti-TB drugs leading to extreme mental health problems such as depression and anxiety in TB patients. To investigate the prevalence of anxiety and depressive symptoms among TB patients, and to explore whether drug resistance is a covariate for depressive and anxiety symptoms, a total of 167 pulmonary tuberculosis patients were enrolled in this study, which was conducted from January 1 to September 30, 2020. Data were collected, using a structured questionnaire with a demographic component, the Hospital Anxiety and Depression Scale (HADS), General Health Questionnaire 20 (GHQ-20), the Tuberculosis-related Stigma Scale (TSS) and the Social Support Rating Scale (SSRS). Association between demographics, disease/treatment characteristics, stigma, social support, and anxiety/depression symptoms were investigated either based on Pearson's correlation coefficient or group comparisons based on independent t-test (or Mann-Whitney U-test) Multiple linear stepwise regression analysis was used for determining the predictors of anxiety and depression. The results showed that multi-drug resistance pulmonary tuberculosis patients were associated with anxiety challenges. Multiple linear regression analysis indicated that self-esteem accounted for 33.5 and 38% of the variation in anxiety and depression, respectively. This shows that among tuberculosis patients, self-esteem is the factor that could most explains the depression and anxiety symptoms of patients, suggesting that we may could through improving the environment, society, and family respect and tolerance of tuberculosis patients, thereby improving the mental health of tuberculosis patients.

Recent Advances in the Development of Protein- and Peptide-Based Subunit Vaccines against Tuberculosis

The World Health Organization (WHO) herald of the “End TB Strategy” has defined goals and targets for tuberculosis prevention, care, and control to end the global tuberculosis endemic. The emergence of drug resistance and the relative dreadful consequences in treatment outcome has led to increased awareness on immunization against Mycobacterium tuberculosis (Mtb). However, the proven limited efficacy of Bacillus Calmette-Guérin (BCG), the only licensed vaccine against Mtb, has highlighted the need for alternative vaccines. In this review, we seek to give an overview of Mtb infection and failure of BCG to control it. Afterward, we focus on the protein- and peptide-based subunit vaccine subtype, examining the advantages and drawbacks of using this design approach. Finally, we explore the features of subunit vaccine candidates currently in pre-clinical and clinical evaluation, including the antigen repertoire, the exploited adjuvanted delivery systems, as well as the spawned immune response.

Use of Calcium Channel Blockers and Risk of Active Tuberculosis Disease: A Population-Based Analysis

Calcium channel blockers (CCBs) are known to reduce the availability of iron-an important mineral for intracellular pathogens. Nonetheless, whether the use of CCBs modifies the risk of active tuberculosis in the clinical setting remains unclear. To determine whether CCBs may modify the risk of active tuberculosis disease, we conducted a nested case-control study using the National Health Insurance Research Database of Taiwan between January 1999 and December 2011. Conditional logistic regression and disease risk score adjustment were used to calculate the risk of active tuberculosis disease associated with CCB use. Subgroup analyses investigated the effect of different types of CCBs and potential effect modification in different subpopulations. A total of 8164 new active tuberculosis cases and 816 400 controls were examined. Use of CCBs was associated with a 32% decrease in the risk of active tuberculosis (relative risk [RR], 0.68 [95% CI, 0.58-0.78]) after adjustment with disease risk score. Compared with nonuse of CCBs, the use of dihydropyridine CCBs was associated with a lower risk of tuberculosis (RR, 0.63 [95% CI, 0.53-0.79]) than nondihydropyridine CCBs (RR, 0.73 [95% CI, 0.57-0.94]). In contrast, use of β-blockers (RR, 0.99 [95% CI, 0.83-1.12]) or loop diuretics (RR, 0.88 [95% CI, 0.62-1.26]) was not associated with lower risk of tuberculosis. In subgroup analyses, the risk of tuberculosis associated with the use of CCBs was similar among patients with heart failure or cerebrovascular diseases. Our study confirms that use of dihydropyridine CCBs decreases the risk of active tuberculosis.

Mycobacterium tuberculosis curli pili (MTP) is associated with significant host metabolic pathways in an A549 epithelial cell infection model and contributes to the pathogenicity of Mycobacterium tuberculosis

INTRODUCTION

A clear understanding of the metabolome of Mycobacterium tuberculosis and its target host cell during infection is fundamental for the development of novel diagnostic tools, effective drugs and vaccines required to combat tuberculosis. The surface-located Mycobacterium tuberculosis curli pili (MTP) adhesin forms initial contact with the host cell and is therefore important for the establishment of infection.

OBJECTIVE

The aim of this investigation was to determine the role of MTP in modulating pathogen and host metabolic pathways in A549 epithelial cells infected with MTP proficient and deficient strains of M. tuberculosis.

METHODS

Uninfected A549 epithelial cells, and those infected with M. tuberculosis V9124 wild-type strain, Δmtp and the mtp-complemented strains, were subjected to metabolite extraction, two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOFMS) and bioinformatic analyses. Univariate and multivariate statistical tests were used to identify metabolites that were significantly differentially produced in the WT-infected and ∆mtp-infected A549 epithelial cell models, comparatively.

RESULTS

A total of 46 metabolites occurred in significantly lower relative concentrations in the Δmtp-infected cells, indicating a reduction in nucleic acid synthesis, amino acid metabolism, glutathione metabolism, oxidative stress, lipid metabolism and peptidoglycan, compared to those cells infected with the WT strain.

CONCLUSION

The absence of MTP was associated with significant changes to the host metabolome, suggesting that this adhesin is an important contributor to the pathogenicity of M. tuberculosis, and supports previous findings of its potential as a suitable drug, vaccine and diagnostic target.