Sung-Pin Tseng1, Wei-Chun Hung2, Hsiao-Jan Chen3, Yu-Tzu Lin3, Hung-Sih Jiang3, Hao-Chieh Chiu3, Po-Ren Hsueh4, Lee-Jene Teng5, Jui-Chang Tsai6. 1. Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan. 2. Department of Microbiology and Immunology, Kaohsiung Medical University, Kaohsiung, Taiwan. 3. Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan. 4. Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan; Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan. 5. Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan. 6. Center for Optoelectronic Medicine, National Taiwan University College of Medicine, Taipei, Taiwan; Department of Surgery, Division of Neurosurgery, National Taiwan University Hospital, Taipei, Taiwan. Electronic address: jctsai@ntu.edu.tw.
Abstract
BACKGROUND/ OBJECTIVES: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) was recognized as a leading pathogen and has been shown to be genetically different from the health care-associated MRSA (HA-MRSA). Photodynamic therapy (PDT) is considered a potential alternative method for the treatment of resistant bacterial infections, but the effect of PDT on CA-MRSA is unknown. The purpose of this study was to compare the bactericidal effects of toluidine blue O (TBO) on CA-MRSA and HA-MRSA and investigate the photodynamic inactivation effects of TBO (TBO-PDI) against bacterial virulence factors. MATERIALS AND METHODS: TBO-PDI effects were determined by measuring the survival fractions for four strains and bactericidal activities for 26 CA-MRSA isolates and 26 HA-MRSA isolates. The influences of TBO-PDI on DNA fragmentation and the activities of protease, lipase, staphylococcal α-hemolysin, and enterotoxin were studied. RESULTS: TBO-PDI has effective bactericidal activity against both CA- and HA-MRSA. However, the bactericidal activity of TBO-PDI was significantly higher against HA-MRSA than CA-MRSA isolates. In addition, TBO-PDI treatment using a sublethal TBO concentration led to reduced production of several virulence factors, including protease, lipase, staphylococcal α-hemolysin, and enterotoxin. CONCLUSION: Although TBO-PDI is slightly less effective against CA-MRSA than HA-MRSA isolates, TBO-PDI could reduce the production of virulence factors at a sublethal TBO concentration, which would be beneficial for treating CA-MRSA infections.
BACKGROUND/ OBJECTIVES: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) was recognized as a leading pathogen and has been shown to be genetically different from the health care-associated MRSA (HA-MRSA). Photodynamic therapy (PDT) is considered a potential alternative method for the treatment of resistant bacterial infections, but the effect of PDT on CA-MRSA is unknown. The purpose of this study was to compare the bactericidal effects of toluidine blue O (TBO) on CA-MRSA and HA-MRSA and investigate the photodynamic inactivation effects of TBO (TBO-PDI) against bacterial virulence factors. MATERIALS AND METHODS:TBO-PDI effects were determined by measuring the survival fractions for four strains and bactericidal activities for 26 CA-MRSA isolates and 26 HA-MRSA isolates. The influences of TBO-PDI on DNA fragmentation and the activities of protease, lipase, staphylococcal α-hemolysin, and enterotoxin were studied. RESULTS:TBO-PDI has effective bactericidal activity against both CA- and HA-MRSA. However, the bactericidal activity of TBO-PDI was significantly higher against HA-MRSA than CA-MRSA isolates. In addition, TBO-PDI treatment using a sublethal TBO concentration led to reduced production of several virulence factors, including protease, lipase, staphylococcal α-hemolysin, and enterotoxin. CONCLUSION: Although TBO-PDI is slightly less effective against CA-MRSA than HA-MRSA isolates, TBO-PDI could reduce the production of virulence factors at a sublethal TBO concentration, which would be beneficial for treating CA-MRSA infections.