LAUSR

AIM To investigate the effects of ALA-PDT on biofilm structure, virulence factor secretion, and quorum sensing (QS) in Pseudomonas aeruginosa. MATERIALS AND METHODS We used confocal laser scanning microscopy (CLSM), an XTT assay, scanning electron microscopy (SEM), a virulence factor assay and qRT-PCR in this study. RESULTS The XTT assay showed that ALA-PDT significantly inhibited the growth of planktonic P. aeruginosa. CLSM and SEM showed that ALA-PDT destroyed both bacterial and biofilm structures. The virulence factor assay showed that pyocyanin and elastase secretion were significantly inhibited in the ALA-PDT groups. qRT-PCR assays demonstrated that ALA-PDT significantly reduced the mRNA expression of QS-related genes. CONCLUSION ALA-PDT kills planktonic and viable biofilm-associated P. aeruginosa cells, destroys biofilm structures, reduces virulence factor secretion and affects QS system gene expression.