Evaluation of Biofilm Inhibitory Activity of Probiotics and Postbiotics Using In Vitro Biofilm Model of Canine Periodontal Disease

Periodontal disease (PD) is one of the most widespread oral inflammatory diseases in dogs, with the potential to cause systemic consequences. The purpose of this study was to evaluate the inhibitory potential of yeast-derived postbiotics and probiotic bacterial strains by using a previously developed in vitro biofilm model mimicking canine PD-associated biofilm including five bacterial species: <i>Neisseria zoodegmatis</i>, <i>Corynebacterium canis</i>, <i>Porphyromonas cangingivalis</i>, <i>Peptostreptococcus canis</i>, and <i>Enterococcus faecalis</i>. After we confirmed the presence of these five bacterial species by employing Fluorescence In Situ Hybridization, the biofilm inhibitory and eradication activity of 11 yeast-derived postbiotics and probiotic bacterial strains, as well as selected dual biotic combinations, against the polymicrobial biofilm were determined using a modified version of the Calgary Biofilm Pin Lid Device and the crystal violet method; additionally, hemolytic activity was evaluated using canine red blood cells. The results show that the inhibitory activity against the polymicrobial PD biofilm ranged from 0% to 22.55%, and eradication ability varied between 0% and 17.28%; however, when combined, the biotics achieved a maximum inhibition rate of 71%. Probiotic strain BC-05 exhibited the lowest in vitro hemolytic activity. Overall, based on the results, four yeast-derived postbiotics and one probiotic bacterial strain were selected as promising candidates for further evaluation, aiming at in vivo application.