Related Experiment Video

Updated: Oct 26, 2025

Identification of Virulence Markers of Mycobacterium abscessus for Intracellular Replication in Phagocytes
08:34

Identification of Virulence Markers of Mycobacterium abscessus for Intracellular Replication in Phagocytes

Published on: September 27, 2018

8.8K

Increased Virulence of Outer Membrane Porin Mutants of Mycobacterium abscessus

Vinicius C N de Moura1, Deepshikha Verma1, Isobel Everall2,3

  • 1Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States.

Frontiers in Microbiology
|August 2, 2021
PubMed

Insights

Chronic pulmonary infections from Mycobacterium abscessus (MABSC) are increasing. Porin gene mutations enhance MABSC virulence, suggesting host adaptation, not antibiotic resistance, drives infection progression.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Genetics

Background:

  • Chronic pulmonary infections caused by Mycobacterium abscessus complex (MABSC) are a growing global health concern.
  • MABSC poses a significant threat to individuals with underlying lung conditions like cystic fibrosis.
  • The molecular basis of MABSC pathogenicity and antibiotic resistance is poorly understood.

Purpose of the Study:

  • To investigate the role of Msp-type porins in MABSC virulence and pathogenicity.
  • To determine if porin gene mutations contribute to antibiotic resistance in MABSC.
  • To understand the evolutionary drivers of MABSC adaptation during infection.

Main Methods:

  • Inactivation of Msp-type porin genes (mmpA and mmpB) in M. abscessus subsp. massiliense using allelic replacement.
  • Assessment of mutant virulence and pathogenicity in murine macrophages and infected mice.
  • Evaluation of antibiotic resistance profiles of the generated mutants.

Main Results:

  • Inactivation of mmpA or mmpB significantly increased MABSC virulence and pathogenicity in both cellular and animal models.
  • The porin mutants did not exhibit increased resistance to antibiotics.
  • These findings indicate that porin alterations are linked to enhanced MABSC host adaptation.

Conclusions:

  • Msp-type porins play a crucial role in modulating MABSC pathogenicity.
  • Host adaptation, rather than antibiotic pressure, appears to be the primary driver for the emergence of porin mutants during MABSC infections.
  • Targeting porin function could be a potential strategy to combat MABSC infections.
Keywords:
Mycobacteriumabscessusantibiotic resistanceporinvirulence

More Related Videos

Deciphering and Imaging Pathogenesis and Cording of Mycobacterium abscessus in Zebrafish Embryos10:38

Deciphering and Imaging Pathogenesis and Cording of Mycobacterium abscessus in Zebrafish Embryos

Published on: September 9, 2015

10.6K
Preparation of Agar Bead Embedded Mycobacterium abscessus to Inoculate Immunocompetent Mice Intratracheally05:40

Preparation of Agar Bead Embedded Mycobacterium abscessus to Inoculate Immunocompetent Mice Intratracheally

Published on: April 25, 2025

1.1K

Related Concept Videos

Porin Insertion in the Outer Mitochondrial Membrane01:12

Porin Insertion in the Outer Mitochondrial Membrane

Porins are beta-barrel proteins translocated to the mitochondrial outer membrane through the TOM complex into the intermembrane space. Porin precursors bind TIM chaperones within the intermembrane space and are guided to the Sorting and Assembly Machinery complex or SAM complex on the outer mitochondrial membrane.
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
3.7K
Defense Against Bacterial Pathogens01:31

Defense Against Bacterial Pathogens

The human immune system is a complex network of cells, tissues, and organs that work together to defend the body against bacterial infections. It consists of various immune cells, each playing a specific role in the defense mechanism.
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
1.7K
Development of Antibiotic Resistance01:30

Development of Antibiotic Resistance

Antibiotic resistance is a major public health concern that arises when bacteria evolve mechanisms to withstand the effects of antibiotic treatments. This resistance can be intrinsic, acquired through genetic mutations, or transferred between bacteria via horizontal gene transfer. The development of antibiotic resistance poses significant challenges in treating bacterial infections and necessitates ongoing research to develop new therapeutic strategies.Intrinsic resistance occurs when bacterial...
636
Gene Regulation in Microbial Communities: Quorum Sensing01:28

Gene Regulation in Microbial Communities: Quorum Sensing

Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...
167
Structure of Porins01:21

Structure of Porins

Mitochondria, chloroplasts, and gram-negative bacteria have transmembrane, beta-barrel proteins called porins to mediate the free diffusion of ions and metabolites across the membrane. Mitochondrial porin precursors contain conserved amino acid sequences called beta signals at their C-terminal. Beta signals have a  motif of PoXGXXHyXHy (Po-Polar, X-Any amino acid, G-Glycine, Hy-LargeHydrophobic), which are crucial for precursor recognition to initiate precursor assembly. Beta-barrel...
3.4K