Recent advances in the treatment of tuberculosis

A Lumbar Drug-Resistant Tuberculosis: A Case Report and Review of Literature

Introduction

Tuberculosis is prevalent in high-burden countries. However, spinal multi-drug resistant tuberculosis (MDR-TB) in patients with normal immune function is a disease that is prone to misdiagnosis and even delayed diagnosis. Recently, we successfully treated one such patient.

Case Presentation

A 46-year-old male patients with lower back pain associated with recurrent fever 2 months before admission. The patient was misdiagnosed as a suppurative spinal infection and failed to respond to treatment for 2 months. The muscle strength of both lower limbs decreased progressively. We performed two operations to clear the lesion and decompress the spinal canal, during which we found a fish-like inflammatory tissue mimicking a suppurative infection. Finally, the patient was diagnosed with lumbar MDR-TB by culture, Xpert MTB/RIF and metagenomic next-generation sequencing (mNGS). The second-line anti-tuberculosis treatment (ATT) is cycloserine + para-aminosalicylic acid + ethambutol + levofloxacin + linezolid. Finally, the patient's symptoms were relieved and the muscle strength of both lower limbs recovered.

Conclusion

This case prompt MDR-TB of the spine is not a typical clinical symptoms and imaging examination is the lack of specificity, when for the diagnosis of patients with spinal bone destruction unclear or treatment is invalid, can diagnostic anti-tuberculosis treatment. For patients with spinal instability or spinal canal occupying, early surgical removal of lesions, tissue culture, Xpert MTB/RIF and mNGS to identify pathogens and drug resistance, timely diagnosis and treatment can maximize the prognosis of spinal MDR-TB.

Applying a Combined Model to Evaluate the Risk of Poor Treatment Outcomes in Rifampicin Resistant Tuberculosis Patients: A Multicenter Retrospective Study

Objective

Treating and managing rifampicin resistant tuberculosis (RR-TB) patients in Yunnan, China, are major challenges. This study aims to evaluate the risk of poor treatment outcomes in RR-TB patients, allowing clinical doctors to proactively target patients who would benefit from enhanced patient management.

Methods

Four RR-TB care facilities in different regions of Yunnan province as the data collection points were selected. A total of 524 RR-TB patients were included in this study and randomly assigned into a training set (n=366) and a validation set (n=158). In the training set, four significant factors were screened by using a random forest model and a Lasso regression model, and then included in a logistic regression model to construct a nomogram for internal validation.

Results

The successful treatment rate of RR-TB patients in training set was 42.6% (156/366), and the main poor treatment outcomes were loss to follow-up (66.7%) and death (18.1%). Low hemoglobin (HGB) (OR=0.977, 95% CI: 0.964-0.989), long-regime (OR=2.784, 95% CI: 1.634-4.842), poor culture results at the end of the 6th month (CR6TM) (OR=11.193, 95% CI: 6.507-20.028), pre-extensively drug-resistant tuberculosis (pre-XDR) (OR=3.736, 95% CI: 1.294-12.034) were risk factors for poor treatment outcomes in RR-TB patients. The Area Under Curve (AUC) of this model was 0.829 (95% CI: 0.787-0.870), and there was good consistency between the predicted probability and the actual probability. The DCA curve showed that when the threshold probability was 20-98%, the use of nomogram to predict the net benefit of poor treatment outcomes risk in RR-TB patients was higher.

Conclusion

We combined multiple models to develop a nomogram for predicting poor treatment outcomes in RR-TB patients. This would help clinical doctors identify high-risk populations and enable them to proactively target RR-TB patients who will benefit from strengthened patient management.

Regulation of ROS metabolism in macrophage via xanthine oxidase is associated with disease progression in pulmonary tuberculosis

BACKGROUND

Pulmonary tuberculosis (PTB) exacerbation can lead to respiratory failure, multi-organ failure, and symptoms related to central nervous system diseases. The purpose of this study is to screen biomarkers and metabolic pathways that can predict the progression of PTB, and to verify the role of the metabolic enzyme xanthine oxidase (XO) in the progression of PTB.

METHODS

To explore the biomarkers and mechanisms underlying the progression of PTB, plasma metabolomics sequencing was conducted on patients with severe PTB, non-severe PTB, and healthy individuals. Screening differential metabolites and metabolic pathways that can predict the progression of PTB, and verifying the function and mechanism of action of XO through experiments.

RESULTS

The purine metabolism, sphingolipid metabolism, and amino acid metabolism between the three groups differ. In patients with severe PTB, the levels of xanthosine and hypoxanthine are increased, while the levels of D-tryptophan, dihydroceramide and uric acid are decreased. Inhibition of XO activity has been observed to reduce the levels of tumor necrosis factor (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6), as well as to suppress the production of reactive oxygen species (ROS) and the activation of the NF-κB pathway, while also promoting the growth of MTB within cells.

CONCLUSION

D-tryptophan, xanthosine, and dihydroceramide can be utilized as biomarkers for progression of PTB, assisting in the evaluation of disease progression, and XO stands out as a potential therapeutic target for impeding the progression of PTB.

Gallbladder tuberculosis mimicking carcinoma: A case report of a rare entity

INTRODUCTION

Gallbladder TB (GBTB) is a rare disease with a non-specific presentation, simulating cholecystitis and gallbladder malignancies. We describe a rare case of infiltrative GBTB with biliary strictures in a young female who was initially diagnosed with metastatic gallbladder carcinoma.

CASE PRESENTATION

A 33-year-old female presented with recurrent episodes of obstructive jaundice, significant weight loss, fatigue, and oligomenorrhoea. Imaging studies revealed features of locally advanced gallbladder carcinoma with proximal and distal common bile duct strictures. However, biopsy of the liver tissue surrounding the gallbladder mass confirmed necrotizing granulomatous inflammation with similar findings from fine needle aspiration of the cervical lymph node. Along with the histopathological findings, radiological evidence of pulmonary tuberculosis confirmed the diagnosis of infiltrative GBTB. The patient was successfully managed with anti-tubercular drugs along with biliary decompression.

DISCUSSION

The rarity of GBTB is attributed to the high alkalinity of bile and bile acids, which afford protection against tubercle bacilli. Patients commonly present with abdominal pain, fever, abdominal lump, anorexia, and weight loss. Biliary strictures, though rare, have been described in GBTB and simulate cholangiocarcinoma. Due to the non-specific findings of pre-operative laboratory and radiological investigations, most patients are taken up for surgery and diagnosed with TB on post-operative histological analysis.

CONCLUSION

Gallbladder TB is a rare disease which poses a diagnostic challenge because it lacks any pathognomonic features. A tissue diagnosis must be carried out before confirming gallbladder and biliary tract malignancies. Physicians in TB-endemic regions should possess a high index of suspicion for diagnosing GBTB.

Exploiting cAMP signaling in Mycobacterium tuberculosis for drug discovery

Mycobacterium tuberculosis (Mtb) replicates within host macrophages by adapting to the stressful and nutritionally constrained environments in these cells. Exploiting these adaptations for drug discovery has revealed that perturbing cAMP signaling can restrict Mtb growth in macrophages. Specifically, compounds that agonize or stimulate the bacterial enzyme, Rv1625c/Cya, induce cAMP synthesis and this interferes with the ability of Mtb to metabolize cholesterol. In murine tuberculosis (TB) infection models, Rv1625c/Cya agonists contribute to reducing relapse and shortening combination treatments, highlighting the therapeutic potential for this class of compounds. More recently, cAMP signaling has been implicated in regulating fatty acid utilization by Mtb. Thus, a new model is beginning to emerge in which cAMP regulates the utilization of host lipids by Mtb during infection, and this could provide new targets for TB drug development. Here, we summarize the current understanding of cAMP signaling in Mtb with a focus on our understanding of how cAMP signaling impacts Mtb physiology during infection. We also discuss additional cAMP-related drug targets in Mtb and other bacterial pathogens that may have therapeutic potential.

Nα-Aroyl-N-Aryl-Phenylalanine Amides: A Promising Class of Antimycobacterial Agents Targeting the RNA Polymerase

Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains the leading cause of death from a bacterium in the world. The global prevalence of clinically relevant infections with opportunistically pathogenic non-tuberculous mycobacteria (NTM) has also been on the rise. Pharmacological treatment of both TB and NTM infections usually requires prolonged regimens of drug combinations, and is often challenging because of developed or inherent resistance to common antibiotic drugs. Medicinal chemistry efforts are thus needed to improve treatment options and therapeutic outcomes. Nα-aroyl-N-aryl-phenylalanine amides (AAPs) have been identified as potent antimycobacterial agents that target the RNA polymerase with a low probability of cross resistance to rifamycins, the clinically most important class of antibiotics known to inhibit the bacterial RNA polymerase. In this review, we describe recent developments in the field of AAPs, including synthesis, structural characterization, in vitro microbiological profiling, structure-activity relationships, physicochemical properties, pharmacokinetics and early cytotoxicity assessment.

Therapeutic developments for tuberculosis and nontuberculous mycobacterial lung disease

Tuberculosis (TB) drug discovery and development has undergone nothing short of a revolution over the past 20 years. Successful public-private partnerships and sustained funding have delivered a much-improved understanding of mycobacterial disease biology and pharmacology and a healthy pipeline that can tolerate inevitable attrition. Preclinical and clinical development has evolved from decade-old concepts to adaptive designs that permit rapid evaluation of regimens that might greatly shorten treatment duration over the next decade. But the past 20 years also saw the rise of a fatal and difficult-to-cure lung disease caused by nontuberculous mycobacteria (NTM), for which the drug development pipeline is nearly empty. Here, we discuss the similarities and differences between TB and NTM lung diseases, compare the preclinical and clinical advances, and identify major knowledge gaps and areas of cross-fertilization. We argue that applying paradigms and networks that have proved successful for TB, from basic research to clinical trials, will help to populate the pipeline and accelerate curative regimen development for NTM disease.

Multidrug-resistant tuberculosis

Tuberculosis (TB) remains the foremost cause of death by an infectious disease globally. Multidrug-resistant or rifampicin-resistant TB (MDR/RR-TB; resistance to rifampicin and isoniazid, or rifampicin alone) is a burgeoning public health challenge in several parts of the world, and especially Eastern Europe, Russia, Asia and sub-Saharan Africa. Pre-extensively drug-resistant TB (pre-XDR-TB) refers to MDR/RR-TB that is also resistant to a fluoroquinolone, and extensively drug-resistant TB (XDR-TB) isolates are additionally resistant to other key drugs such as bedaquiline and/or linezolid. Collectively, these subgroups are referred to as drug-resistant TB (DR-TB). All forms of DR-TB can be as transmissible as rifampicin-susceptible TB; however, it is more difficult to diagnose, is associated with higher mortality and morbidity, and higher rates of post-TB lung damage. The various forms of DR-TB often consume >50% of national TB budgets despite comprising <5-10% of the total TB case-load. The past decade has seen a dramatic change in the DR-TB treatment landscape with the introduction of new diagnostics and therapeutic agents. However, there is limited guidance on understanding and managing various aspects of this complex entity, including the pathogenesis, transmission, diagnosis, management and prevention of MDR-TB and XDR-TB, especially at the primary care physician level.

Treatment outcomes and risk factors for an unsuccessful outcome among patients with highly drug-resistant tuberculosis in Ukraine

OBJECTIVES

To describe demographics, clinical features, and treatment outcomes of patients with highly drug-resistant tuberculosis (TB) in Ukraine, and to evaluate risk factors for an unsuccessful outcome.

METHODS

Data from patients with multi-, pre-extensively, or extensively drug-resistant TB were collected prospectively from TB dispensaries in 15 out of 24 Ukrainian oblasts (regions) from 2020 to 2021. Treatment outcomes were evaluated using WHO definitions. Risk factors for an unsuccessful outcome were identified using a multivariable logistic regression model.

RESULTS

Among 1748 patients, the overall proportion of successful outcomes was 58% (95% confidence interval [95% CI] 56-60) (n = 1015/1748), ranging from 65% (95% CI: 62-69) (n = 531/814) for multidrug-resistant TB to 54% (95% CI: 49-58) (n = 301/563) for pre-extensively drug-resistant TB and 49% (95% CI: 44-55) (n = 183/371) for extensively drug-resistant TB. Results were similar across oblasts, with few exceptions. The strongest risk factors for an unsuccessful outcome were extensively drug-resistant TB (adjusted OR [aOR] 3.23; 95% CI: 1.88-5.53), total serum protein below 62 g/L in adults and below 57 g/L for children and adolescents (aOR 2.79; 95% CI: 1.93-4.04), psychiatric illness (aOR 2.79; 95% CI: 1.46-5.33), age at TB diagnosis >65 years (aOR 2.50; 95% CI: 1.42-4.42), and alcohol misuse (aOR 2.48; 95% CI: 1.89-3.26).

DISCUSSION

The overall proportion of successful outcomes among Ukrainians treated for highly drug-resistant TB was 58%, notably better compared with previous years, but still low for extensively drug-resistant TB. Risk factors for unsuccessful outcomes highlight that addressing socioeconomic factors in TB management is crucial. Efforts in maintaining TB dispensaries during and following the ongoing war are highly warranted.

Study protocol for safety and efficacy of all-oral shortened regimens for multidrug-resistant tuberculosis: a multicenter randomized withdrawal trial and a single-arm trial [SEAL-MDR]

INTRODUCTION

The urgent need for new treatments for multidrug-resistant tuberculosis (MDR-TB) and pre-extensively drug-resistant tuberculosis (pre-XDR-TB) is evident. However, the classic randomized controlled trial (RCT) approach faces ethical and practical constraints, making alternative research designs and treatment strategies necessary, such as single-arm trials and host-directed therapies (HDTs).

METHODS

Our study adopts a randomized withdrawal trial design for MDR-TB to maximize resource allocation and better mimic real-world conditions. Patients' treatment regimens are initially based on drug resistance profiles and patient's preference, and later, treatment-responsive cases are randomized to different treatment durations. Alongside, a single-arm trial is being conducted to evaluate the potential of sulfasalazine (SASP) as an HDT for pre-XDR-TB, as well as another short-course regimen without HDT for pre-XDR-TB. Both approaches account for the limitations in second-line anti-TB drug resistance testing in various regions.

DISCUSSION

Although our study designs may lack the internal validity commonly associated with RCTs, they offer advantages in external validity, feasibility, and ethical appropriateness. These designs align with real-world clinical settings and also open doors for exploring alternative treatments like SASP for tackling drug-resistant TB forms. Ultimately, our research aims to strike a balance between scientific rigor and practical utility, offering valuable insights into treating MDR-TB and pre-XDR-TB in a challenging global health landscape. In summary, our study employs innovative trial designs and treatment strategies to address the complexities of treating drug-resistant TB, fulfilling a critical gap between ideal clinical trials and the reality of constrained resources and ethical considerations.

TRAIL REGISTRATION

Chictr.org.cn, ChiCTR2100045930. Registered on April 29, 2021.

Dual Inhibition of Mycobacterium tuberculosis and the Host TGFBR1 by an Anilinoquinazoline

Tuberculosis (TB) control is complicated by the emergence of drug resistance. Promising strategies to prevent drug resistance are the targeting of nonreplicating, drug-tolerant bacterial populations and targeting of the host, but inhibitors and targets for either are still rare. In a cell-based screen of ATP-competitive inhibitors, we identified compounds with in vitro activity against replicating Mycobacterium tuberculosis (Mtb), and an anilinoquinazoline (AQA) that also had potent activity against nonreplicating and persistent Mtb. AQA was originally developed to inhibit human transforming growth factor receptor 1 (TGFBR1), a host kinase that is predicted to have host-adverse effects during Mtb infection. The structure-activity relationship of this dually active compound identified the pyridyl-6-methyl group as being required for potent Mtb inhibition but a liability for P450 metabolism. Pyrrolopyrimidine (43) emerged as the optimal compound that balanced micromolar inhibition of nonreplicating Mtb and TGFBR1 while also demonstrating improved metabolic stability and pharmacokinetic profiles.