In vitro Interactions between Streptococcus intermedius and Streptococcus salivarius K12 on a Titanium Cylindrical Surface

Abstract

Peri-implantitis is a steadily rising disease and is caused by oral bacterial pathogens able to form biofilm on implant surfaces and peri-implant tissues, making antibiotics treatment less effective. The use of commercial probiotics against oral pathogens could serve as an alternative to prevent biofilm formation. <i>Streptococcus intermedius</i> is one of the early colonizers of biofilm formation in dental implants. The aim of this study was to model the interaction between <i>S. intermedius</i> and <i>Streptococcus salivarius</i> strain K12, a probiotic bacterium producing bacteriocins. <i>S. intermedius</i> was co-cultured with <i>S. salivarius</i> K12 in an in vitro model simulating the biofilm formation in a dental implant composed by a titanium cylinder system. Biofilm formation rate was assessed by Real-Time PCR quantification of bacterial count and expression levels of <i>luxS</i> gene, used in response to cell density in the biofilm. Biofilm formation, bacteriocin production, <i>luxS</i> expression patterns were found to be already expressed within the first 12 h. More importantly, <i>S. salivarius</i> K12 was able to counter the biofilm formation in a titanium cylinder under the tested condition. In conclusion, our dental implant model may be useful for exploring probiotic-pathogen interaction to find an alternative to antibiotics for peri-implantitis treatment.