Related Experiment Video

Updated: May 13, 2026

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
07:10

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues

Published on: February 19, 2019

Effects of subinhibitory concentrations of antibiotics on virulence factor expression by community-acquired

Marie Pierre Otto1, Emilie Martin, Cedric Badiou

  • 1Centre National de Référence des Staphylocoques, Faculté de Médecine Lyon Est, Université de Lyon, Lyon F-69008, France.

The Journal of Antimicrobial Chemotherapy
|March 20, 2013
PubMed
Abstract

Insights

Clindamycin and linezolid effectively reduced virulence factors like Panton-Valentine leucocidin (PVL) and protein A (SpA) in community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). Tigecycline specifically targeted PVL, while other antibiotics showed limited effects.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Pharmacology

Background:

  • Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) poses a significant public health threat.
  • Virulence factors such as Panton-Valentine leucocidin (PVL), α-haemolysin (Hla), and protein A (SpA) contribute to CA-MRSA pathogenicity.
  • Understanding how sub-MICs of antibiotics affect virulence factor expression is crucial for treatment strategies.

Purpose of the Study:

  • To investigate the impact of sub-MICs of five antistaphylococcal antibiotics on the expression of PVL, Hla, and SpA in CA-MRSA.
  • To determine the differential effects of clindamycin, daptomycin, linezolid, tigecycline, and vancomycin on key CA-MRSA virulence factors.

Main Methods:

  • Five distinct CA-MRSA clones were cultured with sub-inhibitory concentrations (1/8, 1/4, 1/2 MIC) of five antibiotics.
  • Relative quantitative RT-PCR was employed to measure mRNA levels of pvl, hla, and spa genes.
  • PVL, Hla, and SpA protein concentrations were quantified using ELISAs in culture supernatants and cell pellets.

Main Results:

  • Clindamycin and linezolid significantly reduced PVL and SpA mRNA levels across all tested strains.
  • Tigecycline demonstrated a notable decrease in PVL and SpA mRNA, while daptomycin and vancomycin showed minimal impact.
  • Clindamycin was the most effective in inhibiting Hla mRNA and protein release, with linezolid showing some effect.

Conclusions:

  • Antibiotic choice and concentration critically influence virulence factor expression in CA-MRSA.
  • Clindamycin and linezolid demonstrate consistent suppression of multiple virulence factors.
  • Tigecycline specifically targets PVL, suggesting potential for targeted therapy, while daptomycin and vancomycin appear less effective at sub-MICs.
Keywords:
PVLleucocidinprotein Aα-haemolysin

More Related Videos

Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus (MRSA)12:18

Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus (MRSA)

Published on: February 9, 2011

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

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...
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...
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,...
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...
Regulation of Bacterial Virulence01:28

Regulation of Bacterial Virulence

Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
Staphylococcal Skin Infections01:29

Staphylococcal Skin Infections

Staphylococcus aureus is a Gram-positive coccus that resides harmlessly on the skin and mucous membranes of healthy individuals. When the skin barrier is breached, it can shift from a commensal to an opportunistic pathogen. This transition is facilitated by surface adhesins, such as clumping factor B and S. aureus surface protein G (SasG), which bind to structural proteins, including loricrin and cytokeratin, in the damaged epidermis. Protein A, another key factor, binds the Fc region of...