Related Experiment Video
Updated: Nov 17, 2025
Standardized In vitro Assays to Visualize and Quantify Interactions between Human Neutrophils and Staphylococcus aureus Biofilms
Published on: June 8, 2022
Structural membrane changes induced by pulsed blue light on methicillin-resistant Staphylococcus aureus (MRSA)
Chynna Bowman1, Violet V Bumah2, Ingrid R Niesman1
1Department of Biology, San Diego State University, San Diego, CA 92182, USA.
Background:
In a recent study we showed that blue light inactivates methicillin-resistant Staphylococcus aureus (MRSA) by perturbing, depolarizing, and disrupting its cell membrane.
Purpose:
The current study presents visual evidence that the observed biochemical changes also result in cell metabolic changes and structural alteration of the cell membrane.
Methods:
Cultures of MRSA were treated with 450 nm pulsed blue light (PBL) at 3 mW/cm2 irradiance, using a sub lethal dose of 2.7 J/cm2 radiant exposure three times at 30-min intervals. Following 24 h incubation at 37 °C, irradiated colonies and control non-irradiated colonies were processed for light and transmission electron microscopy.
Results:
The images obtained revealed three major effects of PBL; (1) disruption of MRSA cell membrane, (2) alteration of membrane structure, and (3) disruption of cell replication.
Conclusion:
These signs of bacterial inactivation at a dose deliberately selected to be sub-lethal supports our previous finding that rapid depolarization of bacterial cell membrane and disruption of cellular function comprise another mechanism underlying photo-inactivation of bacteria. Further, it affirms the potency of PBL.
More Related Videos
09:29In Vivo Investigation of Antimicrobial Blue Light Therapy for Multidrug-resistant Acinetobacter baumannii Burn Infections Using Bioluminescence Imaging
Published on: April 28, 2017
08:25Inactivation of Pathogens via Visible-Light Photolysis of Riboflavin-5′-Phosphate
Published on: April 6, 2022
