Related Experiment Video
Updated: Nov 19, 2025
The Synergistic Effect of Visible Light and Gentamycin on Pseudomona aeruginosa Microorganisms
Published on: July 2, 2013
Granadaene Photobleaching Reduces the Virulence and Increases Antimicrobial Susceptibility of Streptococcus
Sebastian Jusuf1, Pu-Ting Dong2, Jie Hui3
1Department of Biomedical Engineering, Boston University, Boston, MA.
Abstract:
Streptococcus agalactiae, also known as Group B Streptococcus (GBS), is increasingly recognized as a major cause of soft tissue and invasive diseases in the elderly and diabetic populations. Antibiotics like penicillin are used with great frequency to treat these infections, although antimicrobial resistance is increasing among GBS strains and underlines a need for alternative methods not reliant on traditional antibiotics. GBS granadaene pigment is related to the hemolysin/cytolysin of GBS, which is critical for the pathogenesis of GBS diseases. Here, we show that photobleaching granadaene dampens the hemolytic activity of GBS. Furthermore, photobleaching of this antioxidant was found to increase GBS susceptibility to killing by reactive oxygen species like hydrogen peroxide. Treatment with light was also shown to affect GBS membrane permeability and contribute to increased susceptibility to the cell membrane-targeting antibiotic daptomycin. Overall, our study demonstrates dual effects of photobleaching on the virulence and antimicrobial susceptibility of GBS and suggests a novel approach for the treatment of GBS infection.
Insights
Photobleaching the Granadaene pigment in Group B Streptococcus (GBS) reduces its virulence and increases susceptibility to killing by reactive oxygen species and certain antibiotics. This suggests a novel light-based therapy for GBS infections.
Area of Science:
- Microbiology
- Antimicrobial Research
- Biochemistry
Background:
- Streptococcus agalactiae (Group B Streptococcus, GBS) causes significant soft tissue and invasive diseases, particularly in elderly and diabetic individuals.
- Increasing antimicrobial resistance to antibiotics like penicillin necessitates alternative treatment strategies for GBS infections.
- GBS granadaene pigment, linked to hemolysin/cytolysin, plays a crucial role in GBS pathogenesis.
Purpose of the Study:
- To investigate the effects of photobleaching GBS granadaene pigment on GBS virulence.
- To assess the impact of photobleaching on GBS susceptibility to oxidative stress and antibiotics.
- To explore photobleaching as a potential novel therapeutic approach for GBS infections.
Main Methods:
- Photobleaching of GBS granadaene pigment.
- Assessing GBS hemolytic activity post-photobleaching.
- Evaluating GBS susceptibility to hydrogen peroxide (reactive oxygen species).
- Measuring GBS membrane permeability and susceptibility to daptomycin after light treatment.
Main Results:
- Photobleaching granadaene significantly dampened the hemolytic activity of GBS.
- Photobleaching increased GBS susceptibility to killing by reactive oxygen species, such as hydrogen peroxide.
- Light treatment altered GBS membrane permeability, enhancing susceptibility to the antibiotic daptomycin.
Conclusions:
- Photobleaching granadaene exhibits dual effects, reducing GBS virulence and increasing antimicrobial susceptibility.
- This study presents a novel, light-based strategy for combating GBS infections.
- Targeting GBS virulence factors like granadaene offers a promising avenue for alternative antimicrobial therapies.
Related Concept Videos
01:28Antimicrobial Effectiveness
01:28Gene Regulation in Microbial Communities: Quorum Sensing