We use cookies to understand how you use our site and to improve your experience. This includes personalizing content and advertising. To learn more, click here. By continuing to use our site, you accept our use of cookies. Cookie Policy.

Features Partner Sites Information LinkXpress hp
Sign In
Advertise with Us
LGC Clinical Diagnostics

Download Mobile App




TB Culture Methods Determine Relapse and Cure

By LabMedica International staff writers
Posted on 04 Dec 2017
Print article
Image: The BACTEC mycobacterial growth indicator tubes (Photo courtesy of Becton, Dickinson and Company).
Image: The BACTEC mycobacterial growth indicator tubes (Photo courtesy of Becton, Dickinson and Company).
Tuberculosis (TB) kills more people than any other infectious disease, and new regimens are essential. The primary endpoint for confirmatory phase III trials for new regimens is a composite outcome that includes bacteriological treatment failure and relapse.

Patients in clinical trials can have positive cultures after treatment ends that may not necessarily indicate relapse. Such post-treatment positives have been attributed to laboratory cross-contamination leading to a false positive or to the breakdown of an old cavity, releasing organisms into the sputum from a patient who has no signs and symptoms of TB and will eventually be classified as having a favorable outcome, therefore defined as an isolated positive.

A group of scientists collaborating with the MRC Clinical Trials Unit at UCL (London, UK) conducted a randomized placebo-controlled double-blind drug trial of 1,931 patients were randomized across sites in Africa and Asia and followed for 18 months from randomization. During the trial, sputum samples were taken for smear and culture (Löwenstein-Jensen [LJ] and Mycobacteria Growth Indicator Tube [MGIT] in parallel) weekly to 8 weeks during treatment, monthly thereafter to 6 months and 3-monthly thereafter to 18 months from randomization. One sputum sample was collected and inoculated into both LJ medium and MGIT system.

A total of 12,209 sputum samples were available from 1,652 patients; cultures were more often positive on MGIT than LJ. In 1,322 patients with a favorable trial outcome, 126 (9.5%) had cultures that were positive in MGIT compared to 34 (2.6%) patients with positive cultures on LJ. Among patients with a favorable outcome, the incidence of isolated positives on MGIT differed by study laboratory with 21.9% of these coming from one laboratory investigating only 4.9% of patients. Compared to negative MGIT cultures, positive MGIT cultures were more likely to be associated with higher-grade TB symptoms reported within seven days either side of sputum collection in patients with an unfavorable primary outcome, but not in patients with a favorable outcome.

The authors concluded that MGIT can replace LJ in phase III TB trials, but there are implications for the definition of the primary outcome and patient management in trials in such settings. Most importantly, the methodologies differ in the incidence of isolated positives and in their capacity for capturing non-tuberculosis mycobacteria. It emphasizes the importance of effective medical monitoring after treatment ends and consideration of clinical signs and symptoms for determining treatment failure and relapse. The study was published on November 24, 2017, in the journal BMC Medicine.

Related Links:
MRC Clinical Trials Unit at UCL

Gold Member
Veterinary Hematology Analyzer
Exigo H400
Verification Panels for Assay Development & QC
Seroconversion Panels
New
Silver Member
HPV Molecular Controls
ZeptoMetrix® HPV Type 16, 18, 45 & 68 Molecular Controls
New
Fecal DNA Extraction Kit
QIAamp PowerFecal Pro DNA Kit

Print article

Channels

Clinical Chemistry

view channel
Image: The tiny clay-based materials can be customized for a range of medical applications (Photo courtesy of Angira Roy and Sam O’Keefe)

‘Brilliantly Luminous’ Nanoscale Chemical Tool to Improve Disease Detection

Thousands of commercially available glowing molecules known as fluorophores are commonly used in medical imaging, disease detection, biomarker tagging, and chemical analysis. They are also integral in... Read more

Immunology

view channel
Image: The cancer stem cell test can accurately choose more effective treatments (Photo courtesy of University of Cincinnati)

Stem Cell Test Predicts Treatment Outcome for Patients with Platinum-Resistant Ovarian Cancer

Epithelial ovarian cancer frequently responds to chemotherapy initially, but eventually, the tumor develops resistance to the therapy, leading to regrowth. This resistance is partially due to the activation... Read more

Pathology

view channel
Image: The ready-to-use DUB enzyme assay kits accelerate routine DUB activity assays without compromising data quality (Photo courtesy of Adobe Stock)

Sensitive and Specific DUB Enzyme Assay Kits Require Minimal Setup Without Substrate Preparation

Ubiquitination and deubiquitination are two important physiological processes in the ubiquitin-proteasome system, responsible for protein degradation in cells. Deubiquitinating (DUB) enzymes contain around... Read more

Technology

view channel
Image: The HIV-1 self-testing chip will be capable of selectively detecting HIV in whole blood samples (Photo courtesy of Shutterstock)

Disposable Microchip Technology Could Selectively Detect HIV in Whole Blood Samples

As of the end of 2023, approximately 40 million people globally were living with HIV, and around 630,000 individuals died from AIDS-related illnesses that same year. Despite a substantial decline in deaths... Read more

Industry

view channel
Image: The collaboration aims to leverage Oxford Nanopore\'s sequencing platform and Cepheid\'s GeneXpert system to advance the field of sequencing for infectious diseases (Photo courtesy of Cepheid)

Cepheid and Oxford Nanopore Technologies Partner on Advancing Automated Sequencing-Based Solutions

Cepheid (Sunnyvale, CA, USA), a leading molecular diagnostics company, and Oxford Nanopore Technologies (Oxford, UK), the company behind a new generation of sequencing-based molecular analysis technologies,... Read more
Copyright © 2000-2025 Globetech Media. All rights reserved.