Modulating mycobacterial envelope integrity for antibiotic synergy with benzothiazoles.

Developing effective tuberculosis drugs is hindered by mycobacteria's intrinsic antibiotic resistance because of their impermeable cell envelope. Using benzothiazole compounds, we aimed to increase mycobacterial cell envelope permeability and weaken the defenses of Mycobacterium marinum, serving as a model for Mycobacterium tuberculosis Initial hit, BT-08, significantly boosted ethidium bromide uptake, indicating enhanced membrane permeability. It also demonstrated efficacy in the M. marinum-zebrafish embryo infection model and M. tuberculosis-infected macrophages. Notably, BT-08 synergized with established antibiotics, including vancomycin and rifampicin. Subsequent medicinal chemistry optimization led to BT-37, a non-toxic and more potent derivative, also enhancing ethidium bromide uptake and maintaining synergy with rifampicin in infected zebrafish embryos. Mutants of M. marinum resistant to BT-37 revealed that MMAR_0407 (Rv0164) is the molecular target and that this target plays a role in the observed synergy and permeability. This study introduces novel compounds targeting a new mycobacterial vulnerability and highlights their cooperative and synergistic interactions with existing antibiotics.

Targeting Mycobacterium tuberculosis pH-driven adaptation.

Mycobacterium tuberculosis (Mtb) senses and adapts to host environmental cues as part of its pathogenesis. One important cue sensed by Mtb is the acidic pH of its host niche - the macrophage. Acidic pH induces widespread transcriptional and metabolic remodelling in Mtb. These adaptations to acidic pH can lead Mtb to slow its growth and promote pathogenesis and antibiotic tolerance. Mutants defective in pH-dependent adaptations exhibit reduced virulence in macrophages and animal infection models, suggesting that chemically targeting these pH-dependent pathways may have therapeutic potential. In this review, we discuss mechanisms by which Mtb regulates its growth and metabolism at acidic pH. Additionally, we consider the therapeutic potential of disrupting pH-driven adaptations in Mtb and review the growing class of compounds that exhibit pH-dependent activity or target pathways important for adaptation to acidic pH.

Surgery for Central Nervous System Tuberculosis in Children.

Tuberculosis (TB) is the second most common cause of death due to a single infectious agent worldwide after COVID-19. Central nervous system tuberculosis is widely prevalent in the world, especially in the developing countries and continues to be a socioeconomic problem. It is highly devastating form of tuberculosis leading to unacceptable levels of morbidity and mortality despite appropriate antitubercular therapy. The clinical symptoms are varied and nonspecific. They can be easily overlooked. Tuberculous meningitis is the most common presentation and its sequelae viz. vasculitis, infarction and hydrocephalus can be devastating. The ensuing cognitive, intellectual, and endocrinological outcome can be a significant source of morbidity and mortality, especially in resource constrained countries. Early diagnosis and treatment of tuberculous meningitis and institution of treatment is helpful in limiting the course of disease process. The diagnosis of CNS tuberculosis remains a formidable diagnostic challenge. The microbiological methods alone cannot be relied upon. CSF diversion procedures need to be performed at the appropriate time in order to achieve good outcomes. Tuberculous pachymeningitis and arachnoiditis are morbid sequelae of tuberculous meningitis. Tuberculomas present as mass lesions in the craniospinal axis. Tuberculous abscess can mimic pyogenic abscess and requires high index of suspicion. Calvarial tuberculosis is seen in children and responds well to antituberculous chemotherapy. Tuberculosis of the spinal cord is seen similar to intracranial tuberculosis in pathogenesis but with its own unique clinical manifestations and management. Multidrug-resistant tuberculosis is a formidable problem, and alternate chemotherapy should be promptly instituted. The pathogenesis, clinical features, diagnosis, and management of central nervous system tuberculosis in children are summarized. Heightened clinical suspicion is paramount to ensure prompt investigation. Early diagnosis and treatment are essential to a gratifying outcome and prevent complications.

Challenges in Diagnosis of Esophageal Tuberculosis.

Esophageal tuberculosis (TB) is a rare manifestation of extrapulmonary TB, accounting for <0.2% of all TB cases. Esophageal TB most commonly presents with dysphagia, odynophagia, retrosternal pain, and systemic symptoms like decreased appetite, loss of weight, and low-grade fever as associated or other presentations. We report a similar case recently encountered as an elderly male patient presented with chronic dysphagia to solids, loss of appetite, and significant loss of weight. Radiological and endoscopy pictures looked like esophageal cancer with histopathological examination (twice) negative for the same. Diagnosis of esophageal TB was confirmed by GeneXpert Ultra of biopsy sample and histopathological examination was suggestive of granulomatous esophagitis. The patient improved on 6 months antitubercular therapy. The unique aspect of this case was how the lesion mimicked an esophageal carcinoma on imaging which posed a diagnostic challenge.

Uncovering the roles of Mycobacterium tuberculosis melH in redox and bioenergetic homeostasis: implications for antitubercular therapy.

Mycobacterium tuberculosis (Mtb), the pathogenic bacterium that causes tuberculosis, has evolved sophisticated defense mechanisms to counteract the cytotoxicity of reactive oxygen species (ROS) generated within host macrophages during infection. The melH gene in Mtb and Mycobacterium marinum (Mm) plays a crucial role in defense mechanisms against ROS generated during infection. We demonstrate that melH encodes an epoxide hydrolase and contributes to ROS detoxification. Deletion of melH in Mm resulted in a mutant with increased sensitivity to oxidative stress, increased accumulation of aldehyde species, and decreased production of mycothiol and ergothioneine. This heightened vulnerability is attributed to the increased expression of whiB3, a universal stress sensor. The absence of melH also resulted in reduced intracellular levels of NAD+, NADH, and ATP. Bacterial growth was impaired, even in the absence of external stressors, and the impairment was carbon source dependent. Initial MelH substrate specificity studies demonstrate a preference for epoxides with a single aromatic substituent. Taken together, these results highlight the role of melH in mycobacterial bioenergetic metabolism and provide new insights into the complex interplay between redox homeostasis and generation of reactive aldehyde species in mycobacteria. IMPORTANCE: This study unveils the pivotal role played by the melH gene in Mycobacterium tuberculosis and in Mycobacterium marinum in combatting the detrimental impact of oxidative conditions during infection. This investigation revealed notable alterations in the level of cytokinin-associated aldehyde, para-hydroxybenzaldehyde, as well as the redox buffer ergothioneine, upon deletion of melH. Moreover, changes in crucial cofactors responsible for electron transfer highlighted melH's crucial function in maintaining a delicate equilibrium of redox and bioenergetic processes. MelH prefers epoxide small substrates with a phenyl substituted substrate. These findings collectively emphasize the potential of melH as an attractive target for the development of novel antitubercular therapies that sensitize mycobacteria to host stress, offering new avenues for combating tuberculosis.

Synchronization of Mycobacterium life cycle: A possible novel mechanism of antimycobacterial drug resistance evolution and its manipulation.

Mycobacterium Tuberculosis (Mtb) causing Tuberculosis (TB) is a widespread disease infecting millions of people worldwide. Additionally, emergence of drug resistant tuberculosis is a major challenge and concern in high TB burden countries. Most of the drug resistance in mycobacteria is attributed to developing acquired resistance due to spontaneous mutations or intrinsic resistance mechanisms. In this review, we emphasize on the role of bacterial cell cycle synchronization as one of the intrinsic mechanisms used by the bacteria to cope with stress response and perhaps involved in evolution of its drug resistance. The importance of cell cycle synchronization and its function in drug resistance in cancer cells, malarial and viral pathogens is well understood, but its role in bacterial pathogens has yet to be established. From the extensive literature survey, we could collect information regarding how mycobacteria use synchronization to overcome the stress response. Additionally, it has been observed that most of the microbial pathogens including mycobacteria are responsive to drugs predominantly in their logarithmic phase, while they show resistance to antibiotics when they are in the lag or stationary phase. Therefore, we speculate that Mtb might use this novel strategy wherein they regulate their cell cycle upon antibiotic pressure such that they either enter in their low metabolic phase i.e., either the lag or stationary phase to overcome the antibiotic pressure and function as persister cells. Thus, we propose that manipulating the mycobacterial drug resistance could be possible by fine-tuning its cell cycle.

IL-10 and TGF-ß1 may weaken the efficacy of preoperative anti-tuberculosis therapy in older patients with spinal tuberculosis.

Spinal tuberculosis is a common extrapulmonary type that is often secondary to pulmonary or systemic infections. Mycobacterium tuberculosis infection often leads to the balance of immune control and bacterial persistence. In this study, 64 patients were enrolled and the clinicopathological and immunological characteristics of different age groups were analyzed. Anatomically, spinal tuberculosis in each group mostly occurred in the thoracic and lumbar vertebrae. Imaging before preoperative anti-tuberculosis therapy showed that the proportion of abscesses in the older group was significantly lower than that in the younger and middle-aged groups. However, pathological examination of surgical specimens showed that the proportion of abscesses in the older group was significantly higher than that in the other groups, and there was no difference in the granulomatous inflammation, caseous necrosis, inflammatory necrosis, acute inflammation, exudation, granulation tissue formation, and fibrous tissue hyperplasia. B cell number was significantly lower in the middle-aged and older groups compared to the younger group, while the number of T cells, CD4+ T cells, CD8+ T cells, macrophages, lymphocytes, plasma cells, and NK cells did not differ. Meaningfully, we found that the proportion of IL-10 high expression and TGF-ß1 positive in the older group was significantly higher than that in the younger group. TNF-α, CD66b, IFN-γ, and IL-6 expressions were not different among the three groups. In conclusion, there are some differences in imaging, pathological, and immune features of spinal tuberculosis in different age groups. The high expression of IL-10 and TGF-ß1 in older patients may weaken their anti-tuberculosis immunity and treatment effectiveness.

Decentralising DOT for drug-susceptible TB from the health facilities to the community level in Togo.

In Togo, the COVID-19 pandemic paved the way for decentralising directly observed treatment (DOT) to the community level through the evaluation of two innovative community-based DOT approaches-a community health worker-based (CHW-DOT) and family-based (FB-DOT). METHODS We conducted an observational prospective study from April 2021 to January 2022. Sputum conversion at Month 2 and favourable treatment outcomes at Month 6 were assessed and compared between the two groups. Sociodemographic and clinical factors related to these outcomes were identified. RESULTS A total of 182 TB patients were enrolled. The CHW-DOT group had significantly increased odds of sputum conversion (aOR 2.95, 95% CI 1.09-7.98) and lower odds of unsuccessful treatment outcomes (aOR 0.37, 95% CI 0.13-1.1). Non-smokers had 4.85 higher odds of converting than smokers (aOR 4.85, 95% CI 1.76-13.42) and lower odds of an unsuccessful treatment than smokers (aOR 0.11, 95% CI 0.04-0.32). CONCLUSION CHW-DOT is associated with higher sputum smear conversion rates and a more favourable treatment outcome. The use of tobacco, significantly associated with outcomes, also suggests that a smoking cessation component may be a valuable adjunct to a CHW-DOT approach during TB treatment..

An 11-month-old boy with tuberculous meningitis presenting as progressive limb weakness, fever, developmental retardation, and loss of consciousness: a case report.

BACKGROUND: Tuberculous meningitis (TBM) accounts for about 1% of all tuberculosis cases and about 5% of extrapulmonary tuberculosis cases. However, it poses major importance because approximately half of those affected die or become severely disabled. Herein, the successful treatment of an 11-month-old boy with progressive limb weakness, fever, developmental retardation, and loss of consciousness due to tuberculosis, was reported. CASE PRESENTATION: An 11-month-old (Iranian Turk) boy was referred to Loghman Hakim hospital for progressive limb weakness and loss of previously attained developmental milestones for the past 2 months. He also had persistent fever and loss of consciousness for about 14 to 21 days. Before being referred to our center, the patient had been diagnosed with hydrocephalus at another center due to possible acute bacterial meningitis based on a CT scan and MRI imaging. On physical examination, anterior fontanel bulging and neck stiffness were observed on the admission. His body temperature and heart rate were 38.1 C and 86 beats per minute (bpm), respectively. He had left 6 cranial nerve palsy and spastic quadriparesis with a power of grade 3/5. Other systemic examinations were normal. Endoscopic third ventriculostomy (ETV) (and leptomeningeal biopsy) revealed diffuse thickening of the floor and lateral walls of the 3rd ventricle and also a cobblestone appearance in the form of multiple white patchy lesions was detected on the floor of the 3rd ventricle. CSF analysis and polymerase chain reaction confirmed the TB meningitis. During hospitalization, a temporary EVD (external ventricular drain) was initially inserted. Eventually, defervescence was denoted 5-6 days after initiation of anti-TB medications, and a permanent ventriculoperitoneal shunt was inserted due to hydrocephalus. Gradually his truncal and limb tone and motor function improved, as did his emotional responses to his parents and ability to eat. The patient can walk without help in the 15th month following the operation and resolved hydrocephalus demonstrated on follow-up imaging. CONCLUSION: Over half of treated TB meningitis patients die or suffer severe neurological sequelae, mainly due to late diagnosis. Hence, early diagnosis and prompt initiation of TB treatment offer the best chance of a good neurological outcome.

Advances in Antiretroviral Therapy for Patients with Human Immunodeficiency Virus-Associated Tuberculosis.

Tuberculosis is one of the most common opportunistic infections and a prominent cause of death in patients with human immunodeficiency virus (HIV) infection, in spite of near-universal access to antiretroviral therapy (ART) and tuberculosis preventive therapy. For patients with active tuberculosis but not yet receiving ART, starting ART after anti-tuberculosis treatment can complicate clinical management due to drug toxicities, drug-drug interactions and immune reconstitution inflammatory syndrome (IRIS) events. The timing of ART initiation has a crucial impact on treatment outcomes, especially for patients with tuberculous meningitis. The principles of ART in patients with HIV-associated tuberculosis are specific and relatively complex in comparison to patients with other opportunistic infections or cancers. In this review, we summarize the current progress in the timing of ART initiation, ART regimens, drug-drug interactions between anti-tuberculosis and antiretroviral agents, and IRIS.

Revealing the Interaction Mechanism between Mycobacterium tuberculosis GyrB and Novobiocin, SPR719 through Binding Thermodynamics and Dissociation Kinetics Analysis.

With the rapid emergence of drug-resistant strains of Mycobacterium tuberculosis (Mtb), various levels of resistance against existing anti-tuberculosis (TB) drugs have developed. Consequently, the identification of new anti-TB targets and drugs is critically urgent. DNA gyrase subunit B (GyrB) has been identified as a potential anti-TB target, with novobiocin and SPR719 proposed as inhibitors targeting GyrB. Therefore, elucidating the molecular interactions between GyrB and its inhibitors is crucial for the discovery and design of efficient GyrB inhibitors for combating multidrug-resistant TB. In this study, we revealed the detailed binding mechanisms and dissociation processes of the representative inhibitors, novobiocin and SPR719, with GyrB using classical molecular dynamics (MD) simulations, tau-random acceleration molecular dynamics (τ-RAMD) simulations, and steered molecular dynamics (SMD) simulations. Our simulation results demonstrate that both electrostatic and van der Waals interactions contribute favorably to the inhibitors' binding to GyrB, with Asn52, Asp79, Arg82, Lys108, Tyr114, and Arg141 being key residues for the inhibitors' attachment to GyrB. The τ-RAMD simulations indicate that the inhibitors primarily dissociate from the ATP channel. The SMD simulation results reveal that both inhibitors follow a similar dissociation mechanism, requiring the overcoming of hydrophobic interactions and hydrogen bonding interactions formed with the ATP active site. The binding and dissociation mechanisms of GyrB with inhibitors novobiocin and SPR719 obtained in our work will provide new insights for the development of promising GyrB inhibitors.

Evaluation of clinical profiles, imaging findings and antituberculosis treatment outcome in granulomatous mastitis: An Indian scenario.

BACKGROUND: The management of choice for granulomatous mastitis (GM) has yet to be determined but few studies have demonstrated that anti-tubercular treatment (ATT) could be an effective alternative therapeutic option. Hence, the objective of the current study is to determine the clinical feature, radiological imaging findings, and histopathological examination results exhibited by GM and tuberculosis (TB)-proven GM as well as to evaluate the ATT clinical outcome in GM patients. METHODS: The study was performed on 68 GM patients who were referred to the department of pulmonology by the breast clinic (from January 2018 to August 2021). Study populations were categorized into two groups GM and TB-proven GM patients and all were prescribed with standard ATT regimen and were continuously followed up. SPSS version 25 was employed for statistical assessment. RESULTS: Our study showed that 6 patients from GM and 4 patients from the TB-proven GM group got relapsed. For patients who displayed partial remission, ATT treatment was started after assessing the side effects potential. 14.6% (n = 6) and 7.4% (n = 2) patients who initially demonstrated partial remission were also completely cured. ATT treatment curable rate was determined to be 90% (n = 37) and 81.5% (n = 22) for GM and TB-proven GM patients correspondingly. Therefore, the current study demonstrated nil significant differences between groups. CONCLUSION: The current study warrants that ATT therapy could be an effective and better treatment of choice for GM patients irrespective of their clinical condition.

Novel 4-nitroimidazole analogues: synthesis, in vitro biological evaluation, in silico studies, and molecular dynamics simulation.

A new series of 4-nitroimidazole bearing aryl piperazines 7-16, tetrazole 17 and 1,3,4-thiadiazole 18 derivatives was synthesized. All derivatives were screened for their anticancer activity against eight diverse human cancer cell lines (Capan-1, HCT-116, LN229, NCI-H460, DND-41, HL-60, K562, and Z138). Compound 17 proved the most potent compound of the series inhibiting proliferation of most of the selected human cancer cell lines with IC50 values in the low micromolar range. In addition, compound 11 exhibited IC50 values ranging 8.60-64.0 µM against a selection of cancer cell lines. These findings suggest that derivative 17 can potentially be a new lead compound for further development of novel antiproliferative agents. Additionally, 17-18 were assessed for their antibacterial and antituberculosis activity. Derivatives 17 and 18 were the most potent compounds of this series against both Staphylococcus aureus strain Wichita and a methicillin resistant strain of S. aureus (MRSA), as well as against Mycobacterium tuberculosis strain mc26230. The antiviral activity of 7-18 was also evaluated against diverse viruses, but no activity was detected. The docking study of compound 17 with putative protein targets in acute myeloid leukemia had been studied. Furthermore, the molecular dynamics simulation of 17 and 18 had been investigated.

A host-directed oxadiazole compound potentiates antituberculosis treatment via zinc poisoning in human macrophages and in a mouse model of infection.

Antituberculosis drugs, mostly developed over 60 years ago, combined with a poorly effective vaccine, have failed to eradicate tuberculosis. More worryingly, multiresistant strains of Mycobacterium tuberculosis (MTB) are constantly emerging. Innovative strategies are thus urgently needed to improve tuberculosis treatment. Recently, host-directed therapy has emerged as a promising strategy to be used in adjunct with existing or future antibiotics, by improving innate immunity or limiting immunopathology. Here, using high-content imaging, we identified novel 1,2,4-oxadiazole-based compounds, which allow human macrophages to control MTB replication. Genome-wide gene expression analysis revealed that these molecules induced zinc remobilization inside cells, resulting in bacterial zinc intoxication. More importantly, we also demonstrated that, upon treatment with these novel compounds, MTB became even more sensitive to antituberculosis drugs, in vitro and in vivo, in a mouse model of tuberculosis. Manipulation of heavy metal homeostasis holds thus great promise to be exploited to develop host-directed therapeutic interventions.

Bilateral Endoscopic Debridement Combined with Local Antituberculosis Drugs for Thoracic Tuberculosis with Large Paravertebral Abscess: A Multicenter Study with 4-year Follow-Up.

BACKGROUND: Paravertebral abscess represents a prevalent manifestation of thoracic tuberculosis, often necessitating surgical intervention. In this study, we introduced a novel approach by employing bilateral endoscopic debridement (BED) to address large Paravertebral abscesses associated with thoracic tuberculosis, a method not previously proposed in the literature. The clinical efficacy was examined through a comprehensive 4-year follow-up. METHODS: We conducted a retrospective analysis on patients diagnosed with thoracic tuberculosis and paravertebral abscess who underwent BED combined with local antituberculosis drugs (BED + LAD) between February 2015 and February 2019. A total of 29 eligible patients (12 males and 17 females) with a median (interquartile ranges) of 59.0(16.5) years were included in the study. All patients received the BED + LAD treatment. After the surgery, the patients were treated with a 4-drug antituberculosis therapy (Rifampicin, Isoniazid, Pyrazinamide, and Ethambutol). All relevant indicators were meticulously recorded and analyzed. RESULTS: The surgical procedures were successfully completed for all subjects, with an average intraoperative bleeding volume of (25.2 ± 8.9) ml, an average surgical time of (68.4 ± 14.0) minutes, an average fluoroscopy frequency of (21.7 ± 8.2) times, an average hospital stay of (14.2 ± 4.3) days, and an average medication period of (42.1 ± 9.6) weeks. All subjects completed at least a 4-year follow-up period. At the final follow-up, ESR and CRP levels returned to normal, and there was no significant increase in the Cobb angle (P>0.05). CONCLUSIONS: The application of BED + LAD in the treatment of thoracic tuberculosis and paravertebral abscess proved to be a safe, effective, and feasible approach.

Identification of Novel Antimicrobial Compounds Targeting Mycobacterium tuberculosis S-Adenosyl-L-Homocysteine Hydrolase Using Dual Hierarchical In Silico Structure-Based Drug Screening.

The emergence of multidrug-resistant and extensively drug-resistant Mycobacterium tuberculosis (M. tuberculosis) has become a major medical problem. S-adenosyl-L-homocysteine hydrolase (MtSAHH) was selected as the target protein for the identification of novel anti-TB drugs. Dual hierarchical in silico Structure-Based Drug Screening was performed using a 3D compound structure library (with over 150 thousand synthetic chemicals) to identify compounds that bind to MtSAHH's active site. In vitro experiments were conducted to verify whether the nine compounds selected as new drug candidates exhibited growth-inhibitory effects against mycobacteria. Eight of the nine compounds that were predicted by dual hierarchical screening showed growth-inhibitory effects against Mycobacterium smegmatis (M. smegmatis), a model organism for M. tuberculosis. Compound 7 showed the strongest antibacterial activity, with an IC50 value of 30.2 µM. Compound 7 did not inhibit the growth of Gram-negative bacteria or exert toxic effects on human cells. Molecular dynamics simulations of 40 ns using the MtSAHH-Compound 7 complex structure suggested that Compound 7 interacts stably with the MtSAHH active site. These in silico and in vitro results suggested that Compound 7 is a promising lead compound for the development of new anti-TB drugs.