Multidrug-resistant tuberculosis infection and disease in children: a review of new and repurposed drugs

Pediatric Drug-Resistant Tuberculosis: The Current and Future Prospects for Management and Prevention

In the continued battle against one of the oldest enemies known to mankind, Mycobacterium tuberculosis (MTB), the emergence of drug resistance to antituberculosis drugs among children poses multiple challenges for early detection and treatment. Molecular diagnostics and newer drugs like bedaquiline and delamanid have strengthened the armamentarium and helped design convenient, safe, and child-friendly therapeutic regimens against drug-resistant tuberculosis (TB). Preventive strategies like treatment of TB infection among children living in close contact with patients with drug-resistant TB and effective vaccines against TB are currently in the investigative stages of development and implementation. In addition to the implementation of recent novel diagnostics and treatment modalities, effective psychosocial and nutritional support, as well as dedicated monitoring for compliance and adverse effects, are crucial determinants for successful treatment outcomes in these children.

Multidrug-Resistant TB (MDR-TB) and Extensively Drug-Resistant TB (XDR-TB) Among Children: Where We Stand Now

Drug-resistant tuberculosis (DR-TB) has continued to be a global health cataclysm. It is an arduous condition to tackle but is curable with the proper choice of drug and adherence to the drug therapy. WHO has introduced newer drugs with all-oral shorter regimens, but the COVID-19 pandemic has disrupted the achievements and raised the severity. The COVID-19 controlling mechanism is based on social distancing, using face masks, personal protective equipment, medical glove, head shoe cover, face shield, goggles, hand hygiene, and many more. Around the globe, national and international health authorities impose lockdown and movement control orders to ensure social distancing and prevent transmission of COVID-19 infection. Therefore, WHO proposed a TB control program impaired during a pandemic. Children, the most vulnerable group, suffer more from the drug-resistant form and act as the storehouse of future fatal cases. It has dire effects on physical health and hampers their mental health and academic career. Treatment of drug-resistant cases has more success stories in children than adults, but enrollment for treatment has been persistently low in this age group. Despite that, drug-resistant childhood tuberculosis has been neglected, and proper surveillance has not yet been achieved. Insufficient reporting, lack of appropriate screening tools for children, less accessibility to the treatment facility, inadequate awareness, and reduced funding for TB have worsened the situation. All these have resulted in jeopardizing our dream to terminate this deadly condition. So, it is high time to focus on this issue to achieve our Sustainable Development Goals (SDGs), the goal of ending TB by 2030, as planned by WHO. This review explores childhood TB's current position and areas to improve. This review utilized electronic-based data searched through PubMed, Google Scholar, Google Search Engine, Science Direct, and Embase.

Carborane clusters increase the potency of bis-substituted cyclam derivatives against Mycobacterium tuberculosis

Bis-substituted cyclam derivatives have recently emerged as a promising new class of antibacterial agents, displaying excellent activity against drug-resistant Mycobacterium tuberculosis (Mtb) and in vivo efficacy in a zebrafish assay. Herein we report the synthesis and biological activity of new carborane derivatives within this class of antitubercular compounds. The resulting carborane-cyclam conjugates incorporating either hydrophobic closo-1,2-carborane or anionic, hydrophilic nido-7,8-carborane clusters display promising activity in an antibacterial assay employing the virulent Mtb strain H37Rv. The most active of these carborane derivatives exhibit MIC50 values of <1 μM, making them the most active compounds in this unique class of antibacterial cyclams reported to date.

Screening of Microbial Fermentation Products for Anti-M. tuberculosis Activity

Simple Summary

M. tuberculosis (M.tb) is the main pathogen of tuberculosis (TB). The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) M.tb has brought new challenges to the treatment of TB. Therefore, finding new materials for the development of natural anti-TB drugs is crucial to the prevention and treatment of TB. In order to discover new anti-TB drug materials, we isolated microorganisms from the soil and tested the anti-M.tb activity of their fermentation products. The results showed that the four fermentation products had anti-M.tb activities in vitro and in intracellular bacteria. The qPCR results showed that the four fermentation products down-regulated some growth-essential gene expression of M.tb. Thus, we speculated that the fermentation product may exert its anti-M.tb effect by down-regulating the expression of the essential genes of M.tb.

Abstract

Tuberculosis (TB), caused by M. tuberculosis (M.tb), is the leading infectious cause of mortality worldwide. The emergence of drug-resistant M.tb has made the control of TB more difficult. In our study, we investigated the ability of microorganism fermentation products from the soil to inhibit M.tb. We successfully identified four fermentation products (Micromonospora chokoriensis, Micromonospora purpureochromogenes, Micromonospora profundi, Streptomyces flavofungini) that inhibited the growth of M.tb in vitro and in intracellular bacteria at 25 μg/mL MIC. Importantly, the fermentation products decreased some essential gene expression levels for M.tb growth. Our data provide the possibility that microbial fermentation products have potential development value for anti-M.tb drugs.

Pediatric Tuberculosis Management: A Global Challenge or Breakthrough?

Managing pediatric tuberculosis (TB) remains a public health problem requiring urgent and long-lasting solutions as TB is one of the top ten causes of ill health and death in children as well as adolescents universally. Minors are particularly susceptible to this severe illness that can be fatal post-infection or even serve as reservoirs for future disease outbreaks. However, pediatric TB is the least prioritized in most health programs and optimal infection/disease control has been quite neglected for this specialized patient category, as most scientific and clinical research efforts focus on developing novel management strategies for adults. Moreover, the ongoing coronavirus pandemic has meaningfully hindered the gains and progress achieved with TB prophylaxis, therapy, diagnosis, and global eradication goals for all affected persons of varying age bands. Thus, the opening of novel research activities and opportunities that can provide more insight and create new knowledge specifically geared towards managing TB disease in this specialized group will significantly improve their well-being and longevity.

XDR-TB Transmitted from Mother to 10-Month-Old Infant: Diagnostic and Therapeutic Problems

Drug-resistant TB (DR-TB) in children is a special epidemiological, clinical, and diagnostic problem, and its global incidence remains unknown. DR-TB in children is usually of a primary nature and is most often transmitted to the child from a household contact, so these cases reflect the prevalence of DR-TB in the population of adult patients. The risk of infection with Mycobacterium tuberculosis complex (MTBC) in children depends on age, duration of exposure, proximity of contact with the infected person, and the level of source virulence. Most cases of TB in children, especially in infants, are caused by household contacts, where the main sources of infection are parents, grandparents or older siblings. However, there are many documented cases of TB transmission outside the family. The most common source of infection is an adult who is profusely positive for mycobacteria, diagnosed too late, and inadequately treated. It has been estimated that a sputum-positive patient might infect 30–50% of their household members. For this reason, active epidemiological investigation and contact tracing in the environment of sputum-positive patients are the most appropriate methods of identifying infected family members. This paper presents a case report concerning the transmission of extensively drug-resistant TB, Beijing 265 genotype, from a mother to her 10-month-old daughter. It is the first case diagnosed in Poland, and one of very few described in the literature where treatment was effective in the mother and the infant recovered spontaneously.

MDR Tuberculosis Treatment

Multidrug-resistant (MDR) tuberculosis (TB), resistant to isoniazid and rifampicin, continues to be one of the most important threats to controlling the TB epidemic. Over the last few years, there have been promising pharmacological advances in the paradigm of MDR TB treatment: new and repurposed drugs have shown excellent bactericidal and sterilizing activity against Mycobacterium tuberculosis and several all-oral short regimens to treat MDR TB have shown promising results. The purpose of this comprehensive review is to summarize the most important drugs currently used to treat MDR TB, the recommended regimens to treat MDR TB, and we also summarize new insights into the treatment of patients with MDR TB.

Interaction of Host Pattern Recognition Receptors (PRRs) with Mycobacterium Tuberculosis and Ayurvedic Management of Tuberculosis: A Systemic Approach

Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis (Mtb), infects the lungs' alveolar surfaces through aerosol droplets. At this stage, the disease progression may have many consequences, determined primarily by the reactions of the human immune system. However, one approach will be to more actively integrate the immune system, especially the pattern recognition receptor (PRR) systems of the host, which notices pathogen-associated molecular patterns (PAMPs) of Mtb. Several types of PRRs are involved in the detection of Mtb, including Toll-like receptors (TLRs), C-type lectin receptors (CLRs), Dendritic cell (DC) -specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN), Mannose receptor (MR), and NOD-like receptors (NLRs) related to inflammasome activation. In this study, we focus on reviewing the Mtb pathophysiology and interaction of host PPRs with Mtb as well as adverse drug effects of anti-tuberculosis drugs (ATDs) and systematic TB treatment via Ayurvedic medicine.

Two cases of pre-extensively drug resistant tuberculosis in children in Indonesia

Few reports are available on children with pre-extensively drug-resistant tuberculosis (pre-XDR-TB), which is defined as Mycobacterium tuberculosis resistant to both isoniazid and rifampicin plus resistance to either a fluoroquinolone or a second-line injectable drug. Pre-XDR-TB treatment for children usually has been individualized based on drug susceptibility test (DST) results, but treatment remains challenging due to the lack of studies based on existing treatment guidelines in children and lack of availability of the new drugs. We report two cases of pre-XDR-TB in children who have responded well to individualized treatment regimens. Because toxic drugs are used for long duration, close monitoring of adverse drug reactions is important.

Screening of Compounds for Anti-tuberculosis Activity, and in vitro and in vivo Evaluation of Potential Candidates

Tuberculosis (TB) is a debilitating infectious disease responsible for more than one million deaths per year. The emergence of drug-resistant TB poses an urgent need for the development of new anti-TB drugs. In this study, we screened a library of over 4,000 small molecules and found that orbifloxacin and the peptide AK15 possess significant bactericidal activity against Mycobacterium tuberculosis (Mtb) in vitro. Orbifloxacin also showed an effective ability on the clearance of intracellular Mtb and protect mice from a strong inflammatory response but not AK15. Moreover, we identified 17 nucleotide mutations responsible for orbifloxacin resistance by whole-genome sequencing. A critical point mutation (D94G) of the DNA gyrase (gyrA) gene was found to be the key role of resistance to orbifloxacin. The computational docking revealed that GyrA D94G point mutation can disrupt the orbifloxacin–protein gyrase interactions mediated by magnesium ion bridge. Overall, this study indicated the potential ability of orbifloxacin as an anti-tuberculosis drug, which can be used either alone or in combination with first-line antibiotics to achieve more effective therapy on TB.

Recent Progress and Challenges for Drug-Resistant Tuberculosis Treatment

Control of Mycobacterium tuberculosis infection continues to be an issue, particularly in countries with a high tuberculosis (TB) burden in the tropical and sub-tropical regions. The effort to reduce the catastrophic cost of TB with the WHO’s End TB Strategy in 2035 is still obstructed by the emergence of drug-resistant TB (DR-TB) cases as result of various mutations of the MTB strain. In the approach to combat DR-TB, several potential antitubercular agents were discovered as inhibitors for various existing and novel targets. Host-directed therapy and immunotherapy also gained attention as the drug-susceptibility level of the pathogen can be reduced due to the pathogen’s evolutionary dynamics. This review is focused on the current progress and challenges in DR-TB treatment. We briefly summarized antitubercular compounds that are under development and trials for both DR-TB drug candidates and host-directed therapy. We also highlighted several problems in DR-TB diagnosis, the treatment regimen, and drug discovery that have an impact on treatment adherence and treatment failure.

The Prospect of Repurposing Immunomodulatory Drugs for Adjunctive Chemotherapy against Tuberculosis: A Critical Review

Tuberculosis (TB) remains a global health emergency, with an estimated 2 billion people infected across the world, and 1.4 million people dying to this disease every year. Many aspects of the causative agent, Mycobacterium tuberculosis, make this disease difficult for healthcare and laboratory researchers to fight against, such as unique pathophysiology, latent infection and long and complex treatment regimens, thus causing patient non-compliance with the treatment. Development of new drugs is critical for tackling these problems. Repurposing drugs is a promising strategy for generating an effective drug treatment whilst circumventing many of the challenges of conventional drug development. In this regard, the incorporation of immunomodulatory drugs into the standard regimen to potentiate frontline drugs is found to be highly appealing. Drugs of diverse chemical classes and drug categories are increasingly being evidenced to possess antitubercular activity, both in vitro and in vivo. This article explores and discusses the molecular entities that have shown promise in being repurposed for use in anti-TB adjunctive therapy and aims to provide the most up-to-date picture of their progress.

Treatment Outcomes Among Pediatric Patients With Highly Drug-Resistant Tuberculosis: The Role of New and Repurposed Second-Line Tuberculosis Drugs

BACKGROUND

Among pediatric patients with multidrug-resistant tuberculosis (MDR-TB), limited data exist regarding treatment outcomes in the context of the new and repurposed second-line TB drugs (SLDs). We aimed to describe the treatment outcomes among pediatric MDR-TB patients receiving new and repurposed SLDs including the proportion who achieved favorable outcomes.

METHODS

We conducted a retrospective cohort study among pediatric patients (age ≤18 years) treated for MDR-TB in the country of Georgia from 2009 to 2016. A "new and repurposed" SLD regimen was defined as a regimen that included linezolid, bedaquiline, and/or delamanid. Favorable treatment outcome was defined by treatment completion or documented microbial "cure" status at the end of treatment. We assessed the association between the use of the new and repurposed SLDs with MDR-TB treatment outcomes using bivariate analyses and log-binomial regression.

RESULTS

There were 124 pediatric MDR-TB patients (median age: 13.7; interquartile range: 4.6-16.0) initiating treatment; 119 (96.0%) had a treatment outcome recorded and were included in our analyses. Eighteen (15.1%) patients received new and repurposed SLDs from 2015 or later. After adjusting for potential confounders, the proportion achieving favorable MDR-TB treatment outcomes was higher among patients treated with SLD regimens that included new and/or repurposed drugs when compared with those treated without (adjusted risk ratio: 1.17; 95% confidence interval: 0.51-2.72).

CONCLUSIONS

We observed a high proportion of favorable treatment outcomes among pediatric patients with MDR-TB receiving the new and repurposed SLDs. Further studies to evaluate the efficacy and children's tolerability of the new and repurposed SLDs are still warranted.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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