Related Experiment Video

Updated: Jun 27, 2026

Growth of Mycobacterium tuberculosis Biofilms
09:03

Growth of Mycobacterium tuberculosis Biofilms

Published on: February 15, 2012

[Biological properties of M. Tuberculosis W cluster strains]

L N Chernousova, S N Andreevskaia, T G Smirnova

    Problemy Tuberkuleza I Boleznei Legkikh
    |December 17, 2008
    PubMed

    Insights

    Mycobacterium tuberculosis W cluster strains show enhanced survival in macrophages, though not necessarily increased virulence. These findings highlight a key characteristic of W cluster strains in host-pathogen interactions.

    Area of Science:

    • Microbiology
    • Immunology
    • Pathogenesis

    Background:

    • The W cluster of Mycobacterium tuberculosis (M. tuberculosis) is a distinct phylogenetic group.
    • Previous assumptions suggested potential hypervirulence of W cluster strains.

    Purpose of the Study:

    • To investigate the biological characteristics of M. tuberculosis W cluster strains.
    • To compare the in vitro, ex vivo, and in vivo behaviors of W cluster strains.

    Main Methods:

    • Standardized methodology for strain clustering.
    • In vitro and ex vivo experiments using 5,6-[3H]-uracil incorporation to assess mycobacterial replication.
    • In vivo experiments evaluating mycobacterial survival, cultivation, and lung pathology in infected animals.

    Main Results:

    • M. tuberculosis W cluster strains exhibited a moderate multiplication rate in vitro.
    • These strains demonstrated high viability within macrophages (ex vivo).
    • In vivo studies indicated that W cluster strains did not significantly differ in virulence compared to the H37Rv laboratory strain, with variable outcomes.

    Conclusions:

    • The hypothesis of M. tuberculosis W cluster hypervirulence was not supported by this study.
    • A defining feature of W cluster strains is their superior capacity for macrophage survival, irrespective of the infectious dose.

    More Related Videos

    A Tuberculosis Molecular Bacterial Load Assay (TB-MBLA)10:41

    A Tuberculosis Molecular Bacterial Load Assay (TB-MBLA)

    Published on: April 30, 2020

    Polarization of M1 and M2 Human Monocyte-Derived Cells and Analysis with Flow Cytometry upon Mycobacterium tuberculosis Infection10:43

    Polarization of M1 and M2 Human Monocyte-Derived Cells and Analysis with Flow Cytometry upon Mycobacterium tuberculosis Infection

    Published on: September 18, 2020

    Related Concept Videos

    Tuberculosis01:23

    Tuberculosis

    Tuberculosis (TB) remains a significant global health concern, primarily targeting the lungs and spreading through airborne transmission. Infection begins when aerosolized droplet nuclei, expelled by an individual with active TB, are inhaled by another person. These microscopic particles carry Mycobacterium tuberculosis, the causative agent of TB. Upon reaching the alveoli, the bacilli are engulfed by alveolar macrophages. However, due to their specialized lipid-rich cell wall, these pathogens...
    Bacterial Phylum Actinobacteria01:30

    Bacterial Phylum Actinobacteria

    Coryneform bacteria are gram-positive, aerobic, nonmotile rods that exhibit irregular, club-shaped, or V-shaped arrangements. Their V-shape results from snapping division, where the inner cell wall layer forms the cross-wall, while the outer layer remains intact until it ruptures on one side, causing the daughter cells to bend away.The primary genera are Corynebacterium and Arthrobacter. Corynebacterium includes diverse species, ranging from saprophytes to pathogens like Corynebacterium...
    Pulmonary Tuberculosis III01:31

    Pulmonary Tuberculosis III

    Tuberculosis (TB) is a contagious infection primarily affecting the lung parenchyma but which can also affect other body parts. TB can be classified based on disease development, presentation, and the affected anatomical site.
    The first classification is based on the development of the disease, and it includes the following categories:
    Pulmonary Tuberculosis II01:28

    Pulmonary Tuberculosis II

    Tuberculosis, or TB, is a bacterial infectious disease caused by Mycobacterium tuberculosis. While its primary impact is on the lungs, leading to pulmonary tuberculosis, it can also affect various other organs, a condition referred to as extrapulmonary tuberculosis.
    Here is a detailed explanation of its pathophysiology:
    Transmission: The process begins when a person inhales droplet nuclei containing M. tuberculosis. These are typically released into the air when an individual with pulmonary or...
    Pulmonary Tuberculosis I01:29

    Pulmonary Tuberculosis I

    Tuberculosis, often called TB, is a contagious illness primarily caused by Mycobacterium tuberculosis. It mainly affects the lung parenchyma but can also impact other body parts.
    Causative Organism
    The primary infectious agent causing tuberculosis is Mycobacterium tuberculosis, a slow-growing, acid-fast, aerobic rod that exhibits sensitivity to heat and ultraviolet light. Instances of Mycobacterium bovis and Mycobacterium avium contributing to the development of TB infection are rare.
    Mode of...
    Pulmonary Tuberculosis IV01:26

    Pulmonary Tuberculosis IV

    Tuberculosis, more commonly referred to as TB, is an infectious disease stemming from Mycobacterium tuberculosis. While it primarily impacts the lungs, TB can also affect other body areas. Given its severity and global impact, timely and accurate diagnosis is crucial for controlling its spread and improving patient outcomes.
    Several diagnostic approaches are used to detect TB. The conventional method is the Tuberculin Skin Test (TST), also known as the Mantoux test. However, this method has...