10.1177/1056789514562152

Vollständiger Abstract

Worum geht es in dieser Arbeit?

<h4>Background</h4><i>Candida albicans</i> and <i>Pseudomonas aeruginosa</i> are frequently co-isolated from refractory endodontic infections. Antimicrobial photodynamic therapy (aPDT) is a promising adjunctive disinfection strategy; however, its efficacy against polymicrobial communities containing structurally distinct organisms remains unclear.<h4>Objective</h4>To evaluate methylene blue-mediated aPDT at three energy densities (15, 30, and 60 J/cm 2 ) against a dual-species coculture model and to investigate the ecological consequences of differential species susceptibility.<h4>Methods</h4>Dual-species biofilms were established on silicone substrates. Mature cocultures were treated with 100 µM methylene blue and irradiated with 630 nm light-emitting diode (LED) light. Morphological changes were assessed by scanning electron microscopy (SEM); bacterial and fungal viability were quantified by colony forming unit assays on species-selective media.<h4>Results</h4>aPDT produced dose-dependent structural damage to <i>P. aeruginosa</i>. SEM showed approximately 90% morphological reduction, and viable counts fell by approximately 1.95 log 10 (≈99%) at 60 J/cm 2 . <i>C. albicans</i> remained morphologically intact across all energy densities. Selective, dose-dependent bacterial inactivation, confirmed by viable counts, was accompanied by secondary fungal overgrowth. <i>C. albicans</i> proliferation rates reached 460-690% within 18 h.<h4>Conclusions</h4>Differential species susceptibility to methylene blue-mediated aPDT disrupts microbial competitive equilibrium in polymicrobial communities. Optimized aPDT protocols for polymicrobial endodontic infections should incorporate antifungal components to prevent secondary fungal proliferation.

Abstract: PubMed · Datensatz