Lipoteichoic acid from a canine probiotic strain Lacticaseibacillus rhamnosus possesses anti-biofilm capacity against clinically isolated canine periodontopathic Porphyromonas species.

Periodontitis is one of the most prevalent oral infectious diseases in canines which is mainly caused by periodontopathic bacteria such as Porphyromonas spp. Biofilm formation of periodontopathogens is closely related to the development of the disease, as it provides increased resistance against dental medicaments or host immunity. Although we recently demonstrated the anti-biofilm activity of Lactobacillus lipoteichoic acid (LTA), a major cell wall component of Gram-positive bacteria, against various human dental pathogens, the anti-biofilm effects of LTA from canine probiotics on canine periodontopathic Porphyromonas spp. have not been evaluated. Here, we investigated whether LTA purified from healthy canine-derived Lacticaseibacillus rhamnosus (Lr.LTA) affects biofilm formation and pre-formed biofilm of clinically isolated canine periodontopathic Porphyromonas spp., including Porphyromonas gulae, Porphyromonas macacae, and Porphyromonas canoris. We initially purified Lr.LTA through a serial application of butanol extraction, hydrophobic-interaction chromatography, and ion-exchange chromatography and confirmed that the resulting Lr.LTA was of high purity. Lr.LTA effectively suppressed the biofilm formation of P. gulae and P. canoris, but minimally P. macacae, without any effects on the bacterial growth. In addition, the inhibitory effects of Lr.LTA on biofilm formation of P. gulae and P. canoris were more potent than that of P. macacae. Lr.LTA also reduced the pre-formed biofilm of P. gulae and P. canoris, while it rarely affected that of P. macacae. These results suggest that Lr.LTA possesses the anti-biofilm capacity against canine periodontopathic Porphyromonas spp. and can be used as an effective anti-biofilm agent for the prevention and treatment of canine periodontitis caused by infection of Porphyromonas spp.