and Are Able to Incorporate and Influence Gene Expression in a Pre-Formed Biofilm.

Bacterial vaginosis (BV) is associated with a highly structured polymicrobial biofilm on the vaginal epithelium where species presumably play a pivotal role. , , and are vaginal pathogens detected during the early stages of incident BV. Herein, we aimed to analyze the impact of and on a pre-established biofilm using a novel in vitro triple-species biofilm model. Total biofilm biomass was determined by the crystal violet method. We also discriminated the bacterial populations in the biofilm and in its planktonic fraction by using PNA FISH. We further analyzed the influence of and on the expression of key virulence genes of by quantitative PCR. In our tested conditions, and were able to incorporate into pre-established biofilms but did not induce an increase in total biofilm biomass, when compared with 48-h biofilms. However, they were able to significantly influence the expression of , a gene suggested to be associated with biofilm maintenance in . This study suggests that microbial relationships between co-infecting bacteria can deeply affect the biofilm, a crucial marker of BV.