Related Experiment Video

Updated: Aug 18, 2026

Demonstrating a Multi-drug Resistant Mycobacterium tuberculosis Amplification Microarray
07:35

Demonstrating a Multi-drug Resistant Mycobacterium tuberculosis Amplification Microarray

Published on: April 25, 2014

Phenotypic resistance in mycobacteria: is it because I am old or fat that I resist you?

Robert J H Hammond1, Vincent O Baron2, Katarina Oravcova2

  • 1Medical and Biological Sciences Building, University of St Andrews, North Haugh, St Andrews, Fife KY16 9TF, UK rjhh@st-andrews.ac.uk.

The Journal of Antimicrobial Chemotherapy
|July 12, 2015
PubMed
Abstract

Insights

Phenotypic antibiotic resistance in mycobacteria is linked to lipid bodies, not cell age. This finding is crucial for understanding and treating persistent mycobacterial infections.

Area of Science:

  • Microbiology
  • Cell Biology
  • Drug Resistance

Background:

  • Mycobacterial infections often relapse, suggesting underlying mechanisms of persistent or resistant bacteria.
  • Phenotypic resistance, a temporary state not caused by genetic mutation, is a key factor in treatment failure.

Purpose of the Study:

  • To investigate the role of cell age and lipid bodies in the phenotypic resistance of mycobacteria to antibiotics.
  • To determine if lipid-rich cells exhibit differential antibiotic susceptibility compared to lipid-poor cells.

Main Methods:

  • Mycobacterium species (M. smegmatis, M. marinum, M. fortuitum, M. bovis BCG) were cultured.
  • Lipid-rich (LR) and lipid-poor (LP) cells were separated using cell staining and flow cytometry.
  • Minimum bactericidal concentrations (MBCs) were determined for LR and LP cells from young and old cultures.

Main Results:

  • Lipid-rich (LR) cells demonstrated significantly higher antibiotic resistance across all tested mycobacterial species compared to lipid-poor (LP) cells.
  • For Mycobacterium bovis BCG, LR cells showed increased resistance ratios: 5× for rifampicin, 16.7× for isoniazid, 5× for ethambutol, and 5× for ciprofloxacin.
  • This increased phenotypic resistance in LR cells was observed regardless of the age of the bacterial culture.

Conclusions:

  • Phenotypic antibiotic resistance in mycobacteria is directly associated with the presence of intracellular lipid bodies.
  • Cell age does not influence this lipid body-mediated resistance.
  • These findings have significant implications for understanding the persistence of mycobacterial infections and developing strategies to combat relapse.

More Related Videos

Visualization of the Charcoal Agar Resazurin Assay for Semi-quantitative, Medium-throughput Enumeration of Mycobacteria09:57

Visualization of the Charcoal Agar Resazurin Assay for Semi-quantitative, Medium-throughput Enumeration of Mycobacteria

Published on: December 14, 2016

Time-Lapse Epifluorescence Microscopy Imaging of Pseudomonas aeruginosa and Staphylococcus aureus Heterogeneous Phenotypes07:44

Time-Lapse Epifluorescence Microscopy Imaging of Pseudomonas aeruginosa and Staphylococcus aureus Heterogeneous Phenotypes

Published on: February 14, 2025

Related Concept Videos

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...
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...
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...
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...
Mechanism of Antibiotic Resistance in MRSA01:25

Mechanism of Antibiotic Resistance in MRSA

Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and acquisition...
Clinical Significance of Antibiotic Resistance01:25

Clinical Significance of Antibiotic Resistance

Methicillin-resistant Staphylococcus aureus (MRSA) presents a critical public health threat, arising from its capacity to resist β-lactam antibiotics due to acquisition of the mecA gene within the staphylococcal cassette chromosome mec (SCCmec). This gene encodes penicillin-binding protein 2a (PBP2a), which impairs binding efficacy of methicillin and other β-lactams. MRSA has evolved into distinct clonal lineages impacting humans and animals alike, reinforcing its significance within the One...