Effect of a bacterial glutaminyl cyclase inhibitor on multi-species-biofilms

In all biofilms, total bacterial counts and those of <i>Pg</i> and <i>Tf</i> remained unaffected by the inhibitor. In the 12-species biofilm, both biomass and total metabolic activity decreased at high inhibitor concentrations (500 µM to 75.2 ± 6.5% and 87.2 ± 5.8%, respectively; each <i>p</i> < 0.001). The arginine-specific amidolytic activities of Rgp declined dose-dependently, down to 60.4 ± 10.2% (<i>p</i> < 0.001) at 500 µM of the inhibitor. Consequently, <i>Pg</i> colonies lost pigmentation as inhibitor concentrations increased. The inhibitor also reduced IL-1β release from monocytic cells stimulated by the 12-species biofilm. The studied [4,5-c]pyridine-based inhibitor is able to modify virulence of a multispecies biofilm. It might have the potential to be a promising approach in periodontal prevention and therapy.