Screening and evaluation of Mycobacterium tuberculosis diagnostic antigens

Diagnostics of Tuberculosis with Single-Walled Carbon Nanotube-Based Field-Effect Transistors

Tuberculosis (TB) is still threatening millions of people's lives, especially in developing countries. One of the major factors contributing to the ongoing epidemic of TB is the lack of a fast, efficient, and inexpensive diagnostic strategy. In this work, we developed a semiconducting single-walled carbon nanotube (SWCNT)-based field-effect transistor (FET) device functionalized with anti-Mycobacterium tuberculosis antigen 85B antibody (Ab85B) to detect the major M. tuberculosis-secreted antigen 85B (Ag85B). Through optimizing the device fabrication process by evaluating the mass of the antibody and the concentration of the gating electrolyte, our Ab85B-SWCNT FET devices achieved the detection of the Ag85B spiked in phosphate-buffered saline (calibration samples) with a limit of detection (LOD) of 0.05 fg/mL. This SWCNT FET biosensor also showed good sensing performance in biological matrices including artificial sputum and can identify Ag85B in serum after introducing bovine serum albumin (BSA) into the blocking layer. Furthermore, our BSA-blocked Ab85B-SWCNT FET devices can distinguish between TB-positive and -negative clinical samples, promising the application of SWCNT FET devices in point-of-care TB diagnostics. Moreover, the robustness of this SWCNT-based biosensor to the TB diagnosis in blood serum was enhanced by blocking SWCNT devices directly with a glutaraldehyde cross-linked BSA layer, enabling future applications of these SWCNT-based biosensors in clinical testing.

A soft-computation hybrid method for search of the antibiotic-resistant gene in Mycobacterium tuberculosis for promising drug target identification and antimycobacterial lead discovery

Tuberculosis (TB) control programs were already piloted before the COVID-19 pandemic commenced and the global TB response was amplified by the pandemic. To combat the global TB epidemic, drug repurposing, novel drug discovery, identification and targeting of the antimicrobial resistance (AMR) genes, and addressing social determinants of TB are required. The study aimed to identify AMR genes in Mycobacterium tuberculosis (MTB) and a new anti-mycobacterial drug candidate. In this research, we used a few software to explore some AMR genes as a target protein in MTB and identified some potent antimycobacterial agents. We used Maestro v12.8 software, along with STRING v11.0, KEGG and Pass Server databases to gain a deeper understanding of MTB AMR genes as drug targets. Computer-aided analysis was used to identify mtrA and katG AMR genes as potential drug targets to depict some antimycobacterial drug candidates. Based on docking scores of -4.218 and -6.161, carvacrol was identified as a potent inhibitor against both drug targets. This research offers drug target identification and discovery of antimycobacterial leads, a unique and promising approach to combating the challenge of antibiotic resistance in Mycobacterium, and contributes to the development of a potential futuristic solution.

A systematic review of potential screening biomarkers for active TB disease

INTRODUCTION

The standard TB Four Symptom Screen does not meet the World Health Organization (WHO) ideal screening criteria for having greater than 90% sensitivity to identify active TB disease, regardless of HIV status. To identify novel screening biomarkers for active TB, we performed a systematic review of any cohort or case-control study reporting associations between screening biomarkers and active TB disease.

METHODS

We searched PubMed and Embase for articles published before October 10, 2021. We included studies from high or medium tuberculosis burden countries. We excluded articles focusing on C-reactive protein and lipoarabinomannan. For all included biomarkers, we calculated sensitivity, specificity and 95% confidence intervals, and assessed study quality using a tool adapted from the QUADAS-2 risk of bias.

RESULTS

From 8,062 abstracts screened, we included 79 articles. The articles described 302 unique biomarkers, including host antibodies, host proteins, TB antigens, microRNAs, whole blood gene PCRs, and combinations of biomarkers. Of these, 23 biomarkers had sensitivity greater than 90% and specificity greater than 70%, meeting WHO criteria for an ideal screening test. Among the eleven biomarkers described in people living with HIV, only one had a sensitivity greater than 90% and specificity greater than 70% for active TB.

CONCLUSION

Further evaluation of biomarkers of active TB should be pursued to accelerate identification of TB disease.