TY - JOUR
T1 - Chitosan inhibits the rehabilitation of damaged microbes induced by photodynamic inactivation
AU - Lin, Ching Hsuan
AU - Chien, Hsiung Fei
AU - Lin, Ming Hsuan
AU - Chen, Chueh Pin
AU - Shen, Mandy
AU - Chen, Chin Tin
N1 - Publisher Copyright:
© 2018 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2018/9/1
Y1 - 2018/9/1
N2 - Previously, we showed that chitosan could augment the biocidal efficacy mediated by photodynamic treatment against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. In this study, we showed that the antimicrobial action of chitosan in augmenting photodynamic inactivation (PDI) is related to the increase in cell surface destruction. The microbial cell surfaces exhibit severe irregular shapes after PDI in the presence of chitosan as demonstrated by transmitted electron microscopy. Furthermore, increases in the concentration or incubation time of chitosan significantly reduced the amounts of photosensitizer toluidine blue O required, indicating that chitosan could be an augmenting agent used in conjunction with PDI against S. aureus, P. aeruginosa, and C. albicans. A prolonged lag phase was found in microbial cells that survived to PDI, in which chitosan acted to completely eradicate the cells. Once the exponential log stage and cell rebuild began, their cellular functions from PDI-induced damage returned and the increased cytotoxic effect of chitosan disappeared. Together, our results suggest that chitosan can prevent the rehabilitation of PDI-surviving microbial cells, leading to increased biocidal efficacy.
AB - Previously, we showed that chitosan could augment the biocidal efficacy mediated by photodynamic treatment against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. In this study, we showed that the antimicrobial action of chitosan in augmenting photodynamic inactivation (PDI) is related to the increase in cell surface destruction. The microbial cell surfaces exhibit severe irregular shapes after PDI in the presence of chitosan as demonstrated by transmitted electron microscopy. Furthermore, increases in the concentration or incubation time of chitosan significantly reduced the amounts of photosensitizer toluidine blue O required, indicating that chitosan could be an augmenting agent used in conjunction with PDI against S. aureus, P. aeruginosa, and C. albicans. A prolonged lag phase was found in microbial cells that survived to PDI, in which chitosan acted to completely eradicate the cells. Once the exponential log stage and cell rebuild began, their cellular functions from PDI-induced damage returned and the increased cytotoxic effect of chitosan disappeared. Together, our results suggest that chitosan can prevent the rehabilitation of PDI-surviving microbial cells, leading to increased biocidal efficacy.
KW - Cell wall
KW - Microbial killing
KW - Photodynamic treatment
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U2 - 10.3390/ijms19092598
DO - 10.3390/ijms19092598
M3 - Article
AN - SCOPUS:85052739490
SN - 1661-6596
VL - 19
JO - International Journal of Molecular Sciences
JF - International Journal of Molecular Sciences
IS - 9
M1 - 2598
ER -