Avaliação dos efeitos de Lacticaseibacillus paracasei na expressão de fatores de patogenicidade de Aggregatibacter actinomycetemcomitans

Abstract

Periodontal disease (PD) is an inflammatory condition of infectious etiology, associated with dysbiosis of the oral microbiota, and is one of the most prevalent oral health issues worldwide. Aggregatibacter actinomycetemcomitans (Aa) is a key microorganism linked to PD, particularly periodontitis. On the other hand, Lacticaseibacillus paracasei is a prominent probiotic bacterium with antibacterial activity and the ability to disrupt biofilm formation by periodontopathogens. Due to the absence of a definitive treatment for PD, new treatment alternatives are being explored, such as the use of probiotics to control and reverse dysbiosis, as this represent a less invasive and less harmful strategy. Thus, the aim of this study was to evaluate the effects of L. paracasei on the biofilm production and expression of virulence factors of A. actinomycetemcomitans during co-culture. For this purpose, Aa and L. paracasei were used at concentrations of 1 x 10⁷ CFU/ml and 1 x 10⁶ CFU/ml. This study demonstrated the ability of L. paracasei cells or supernatant to reduce the biofilm biomass produced by Aa. Both neutralized and non-neutralized supernatants exhibited a negative effect on biofilm formation. Although protease and enzyme assays were performed, the underlying mechanism involved in this effect remains unclear, whether it is due to a single molecule or a synergistic action of multiple factors. Additionally, there was negative regulation of several genes critical for Aa virulence, including ltxA, cdtB, aae, flp, and dspB. These findings strengthen the ability of L. paracasei cells and supernatant to reduce the virulence of Aa and contribute to the treatment of PD.