Denture acrylic biofilms: microbial composition, interactions and infection.

Denture-associated stomatitis (DS), a frequent infection in denture-wearers (up to 60%), presents as areas of palatal inflammation and is normally associated with denture biofilms containing Candida albicans. However, the contribution of co-existing bacteria in these biofilms to the infection remains unclear. As current DS management strategies are primarily directed towards Candida, research demonstrating the impact of specific bacteria upon infection prognosis is important to improve treatment regimes. This research evaluated the in vitro impact of bacteria on Candida virulence, and compared bacterial microbiomes at specific oral sites in DS and non-DS patients to determine associations with infection. In vitro biofilm studies assessed expression of C. albicans virulence factors (morphological transformation, adhesins, hydrolytic enzymes) and their impact on pathogenesis in an infection model. In clinical studies, microbiological samples were obtained from the tongue, palate and denture-fitting surface of 19 denture-wearing patients (DS n=8, non-DS n=11). The presence of Candida was ascertained by PCR. Bacterial DNA was extracted and subjected to next generation sequencing using bacterial 16S rRNA gene targets, and differences in the bacterial microbiomes determined. Certain bacterial species in acrylic biofilms significantly (P