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Updated: May 11, 2026

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
Published on: February 19, 2019
Agr function is upregulated by photodynamic therapy for Staphylococcus aureus and is related to resistance to
Hee Jeong Park1, Yeon-Hee Moon, Hyo-Eun Yoon
1Department of Microbiology and Immunology, Chosun University School of Dentistry, Gwangju, 501-759, Korea.
Abstract:
Photodynamic therapy (PDT) has been considered a feasible alternative for antimicrobial therapy of multidrug-resistant pathogens. However, bacterial response mechanisms against PDT-generated photo-oxidative stress remain largely unknown. Herein, it is shown that the accessory gene regulator Agr is involved in Staphylococcus aureus response to photo-oxidative stress generated by laser-induced PDT with the photosensitizer chlorin e6 . Transcriptional profiling revealed that sublethal PDT induces a general stress response and also activates Agr-dependent gene regulation. Moreover, mutant S. aureus lacking Agr function showed hypersusceptibility to two independent PDT conditions with higher energy densities, demonstrating Agr-dependent S. aureus resistance against PDT.
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