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

Pre-extensively drug-resistant and extensively drug-resistant tuberculosis in Latin America and the Caribbean: A systematic review and meta-analysis

BACKGROUND

The growing threat from pre-extensively drug-resistant tuberculosis (pre-XDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) poses a major public health concern in Latin America and the Caribbean (LAC). Therefore, this study aimed to summarize the available evidence on the prevalence of pre-XDR-TB and XDR-TB among patients with multidrug-resistant tuberculosis in LAC.

METHODS

A systematic review was conducted in the following databases on June 3, 2023: PubMed, Scopus, Ovid Medline, Web of Science, Scielo and LILACS. We estimated pooled proportions using a random effects model (Dersimonian and Laird). The 95% confidence intervals (95% CI) were calculated using the binomial exact method (Clopper-Pearson Method). Subgroup (by time period and country) and sensitivity analyses were performed.

RESULTS

Twenty-nine studies were eligible for qualitative synthesis and 27 for meta-analysis (n = 15,565). The pooled prevalence of XDR-TB in the study participants was 5% (95% CI: 3%-6%), while that of pre-XDR-TB was 10% (95% CI 7%-14%). Cuba (6%, 95% CI 0%-17%) and Peru (6%, 95% CI 5%-7%) had the highest pooled prevalence of XDR-TB. Regarding pre-XDR-TB, Brazil (16%, 95% CI 11%-22%) and Peru (13%, 95% CI: 9%-16%) showed the highest prevalence.

CONCLUSIONS

The pooled prevalence of pre-XDR-TB and XDR-TB in LAC was 10% and 5%, respectively. Governments should strengthen drug-resistance surveillance and TB programs.

Hypersensitivity reactions with first-line antituberculosis drugs and outcomes of rapid desensitizations

Background

Data about drug hypersensitivity reactions with first-line antituberculosis drugs and their management is limited. Rapid drug desensitization seems to be an appropriate management.

Objective

Evaluate the efficacy of the rapid desensitization protocols in patients who had a reaction phenotypically compatible with immediate-type drug hypersensitivity with first-line antituberculosis drugs and identify possible risk factors of breakthrough reactions during the protocols.

Methods

This is a retrospective study of active tuberculosis patients who had a reaction phenotypically compatible with immediate-type drug hypersensitivity with first-line antituberculosis drugs and underwent desensitization with the drugs used during the reaction. Characteristics of drug hypersensitivity and breakthrough reactions, and outcomes of rapid desensitizations were recorded.

Results

One hundred and seventy-nine patients were included in the study. Most of the initial reactions (n = 132, 73.7%) occurred within the first week of treatment and were mild (n = 146, 81.6%). A total of 690 desensitizations were performed. Desensitizations were successfully completed without any breakthrough reaction in 103 (57.5%) patients and in 29 of 36 (80.6%) patients after a breakthrough reaction. The overall success of desensitizations were found to be 95% (132 of 139 patients). Most of the breakthrough reactions (84%) were mild. Sixteen patients had breakthrough reactions with multiple drugs. Although pyrazinamide was the most common culprit of breakthrough reactions and had the lowest desensitization success, it had the highest rate of a single breakthrough reaction (p < 0.001). Timing of the initial reaction and concomitant breakthrough reaction with ethambutol were found to have increased the risk for breakthrough reaction caused by rifampicin (p = 0.017 and p = 0.010 respectively).

Conclusion

The rapid desensitization protocols used in this study provide a successful and effective management of the patients with a reaction phenotypically compatible with immediate-type drug hypersensitivity with first-line antituberculosis drugs.

Global treatment outcomes of extensively drug-resistant tuberculosis in adults: A systematic review and meta-analysis

INTRODUCTION

Historically, extensively drug-resistant tuberculosis has been notoriously difficult to treat with devasting outcomes. As we are coming to the end of an era where the 2006 extensively drug-resistant tuberculosis definitions and old treatment regimens are being replaced, we aimed to estimate the proportion of extensively drug-resistant tuberculosis patients globally who achieved successful treatment outcomes.

METHODS

We conducted a systematic review of PubMed/MEDLINE, Scopus, Web of Science, and Embase from January 1, 2005, through April 3, 2023. Included studies reported WHO treatment outcomes, or adaptions hereof, for pre-extensively and/or extensively drug-resistant tuberculosis patients according to the 2006 WHO definition. Eligible studies included cohorts of at least 10 adults (aged>18 years) that were not pregnant. Using a random-effects model, we calculated pooled proportions of treatment outcomes and performed sensitivity and subgroup analyses. PROSPERO registration number: CRD42022340961.

RESULTS

Among 5056 studies reviewed, we identified 94 studies from 26 countries, involving 10,223 extensively drug-resistant tuberculosis patients. The pooled proportion of successful treatment outcomes was 44.2% (95%CI: 38.3-50.3). Sensitivity analyses consistently produced similar estimates. A slight improvement in treatment outcomes was observed after 2013. Furthermore, 25 studies reported outcomes for 3564 individuals with pre-extensively drug-resistant tuberculosis, of which 63.3% achieved successful treatment (95%CI: 43.1-72.5).

CONCLUSION

Globally, the success rate of extensively drug-resistant tuberculosis treatment is 44.2%, far below the WHO's target rate of 75%. These results may serve as a reference for future studies assessing extensively drug-resistant tuberculosis treatment outcomes under the 2021 definition treated with better treatment regimens available. Comprehensive surveillance data of extensively drug-resistant tuberculosis outcomes from the whole world are desirable to monitor treatment progress.

Medicinal Plants as Therapeutic Alternatives to Combat Mycobacterium tuberculosis: A Comprehensive Review

Tuberculosis (TB) is a serious infectious disease caused by Mycobacterium tuberculosis (MTB) and a significant health concern worldwide. The main threat to the elimination of TB is the development of resistance by MTB to the currently used antibiotics and more extended treatment methods, which is a massive burden on the health care system. As a result, there is an urgent need to identify new, effective therapeutic strategies with fewer adverse effects. The traditional medicines found in South Asia and Africa have a reservoir of medicinal plants and plant-based compounds that are considered another reliable option for human beings to treat various diseases. Abundant research is available for the biotherapeutic potential of naturally occurring compounds in various diseases but has been lagging in the area of TB. Plant-based compounds, or phytoproducts, are being investigated as potential anti-mycobacterial agents by reducing bacterial burden or modulating the immune system, thereby minimizing adverse effects. The efficacy of these phytochemicals has been evaluated through drug delivery using nanoformulations. This review aims to emphasize the value of anti-TB compounds derived from plants and provide a summary of current research on phytochemicals with potential anti-mycobacterial activity against MTB. This article aims to inform readers about the numerous potential herbal treatment options available for combatting TB.

Bacteriophages of Mycobacterium tuberculosis, their diversity, and potential therapeutic uses: a review

Tuberculosis (TB) caused by Mycobacterium tuberculosis (M. tuberculosis) is a highly infectious disease and worldwide health problem. Based on the WHO TB report, 9 million active TB cases are emerging, leading to 2 million deaths each year. The recent emergence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) strains emphasizes the necessity to improve novel therapeutic plans. Among the various developing antibacterial approaches, phage therapy is thought to be a precise hopeful resolution. Mycobacteriophages are viruses that infect bacteria such as Mycobacterium spp., containing the M. tuberculosis complex. Phages and phage-derived proteins can act as promising antimicrobial agents. Also, phage cocktails can broaden the spectrum of lysis activity against bacteria. Recent researches have also shown the effective combination of antibiotics and phages to defeat the infective bacteria. There are limitations and concerns about phage therapy. For example, human immune response to phage therapy, transferring antibiotic resistance genes, emerging resistance to phages, and safety issues. So, in the present study, we introduced mycobacteriophages, their use as therapeutic agents, and their advantages and limitations as therapeutic applications.