AUTHOR=Pourhajibagher Maryam , Rokn Amir Reza , Rostami-Rad Mehdi , Barikani Hamid Reza , Bahador Abbas 

TITLE=Monitoring of Virulence Factors and Metabolic Activity in Aggregatibacter Actinomycetemcomitans Cells Surviving Antimicrobial Photodynamic Therapy via Nano-Chitosan Encapsulated Indocyanine Green

JOURNAL=Frontiers in Physics

VOLUME=6

YEAR=2018

URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2018.00124

DOI=10.3389/fphy.2018.00124

ISSN=2296-424X

ABSTRACT=<p><italic>Aggregatibacter actinomycetemcomitans</italic> is an etiological agent frequently found in both chronic and aggressive periodontitis as well as peri-implantitis. This study assessed the effect of antimicrobial photodynamic therapy (aPDT), as an alternative treatment modality, by nano-chitosan encapsulated indocyanine green (CNPs/ICG), as a photosensitizer, on the virulence features of cell-surviving aPDT against <italic>A. actinomycetemcomitans</italic>. The cell cytotoxicity effect of CNPs/ICG was evaluated on primary human gingival fibroblast cells. <italic>A. actinomycetemcomitans</italic> ATCC 33384 photosensitized with CNPs/ICG was irradiated with diode laser at a wavelength of 810 nm for 1 min (31.2 J/cm<sup>2</sup>), and then bacterial viability measurements were done. The biofilm formation ability, metabolic activity, and antimicrobial susceptibility profiles were assessed for cell-surviving aPDT. The effect of aPDT on the expression of the <italic>fieF</italic> virulent gene, encoding the ferrous-iron efflux pump, was evaluated by the quantitative real-time PCR. CNPs/ICG-aPDT resulted in a significant reduction of cell viability (91%), biofilm formation capacity (53%), and metabolic activity (48%) of <italic>A. actinomycetemcomitans</italic> when compared to the control group (<italic>P</italic> &lt; 0.05). Moreover, <italic>fieF</italic> gene expression was downregulated by 14.8 folds after the strains were treated with aPDT. The virulence of <italic>A. actinomycetemcomitans</italic> strain reduced in cells surviving aPDT with CNPs/ICG, indicating the potential implications of aPDT for the treatment of <italic>A. actinomycetemcomitans</italic> infections in periodontitis and peri-implantitis <italic>in vivo</italic>.</p>