The emergence of antimicrobial resistance remains one of the greatest public health concerns. Biofilm formation has been postulated as a mechanism of microbial pathogens to resist antimicrobial agents. Lactic Acid Bacteria (LAB) and their metabolites have been proposed to combat bacterial biofilms, due to their antimicrobial activity. In this vein, the aim of the present study was to investigate the biofilm removal potential of cell-free supernatant (CFS) of five wild-type Lacticaseibacillus rhamnosus LAB strains, isolated from Greek natural products, in comparison to the commercial available L. rhamnosus GG strain, formed by common foodborne pathogens (Salmonella Enteritidis, Salmonella Typhimurium, Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus). Biofilm removal activity of LAB was assessed on two-days mature biofilm using a microtiter plate-based procedure. Both non-neutralized and neutralized CFSs removed biofilms in a concentration-dependent manner. Biofilm removal activity of the non-neutralized CFSs was significantly higher compared to the neutralized CFSs, as expected, ranging 40 – 90% and 10 – 78%, respectively. Biofilm removal efficiency of L. rhamnosus OLXAL-3 was signifanctly higher among the wild-type L. rhamnosus strains tested (20 – 100% v/v). In conclusion, our results suggested the great potential of application of wild-type Lacticaseibacillus rhamnosus strains CFSs as effective natural agents against pathogenic bacterial biofilms.

Type-1 Diabetes Mellitus (T1D) onset and development is closely linked with imbalance of gut microbiome, while supplementation with probiotics may result in positive alterations in gut microbiome composition. In the present study, the effect of a dietary intervention including free or immobilized cells of the presumptive probiotic Pediococcus acidilactici ORE5 on Corinthian currants, a food with beneficial impact in the condition of diabetes, was investigated. Male Wistar rats were studied which were divided into 4 groups: healthy animals, which received the free (H_FP) or the immobilized cells (H_IPC), and diabetic animals, which received the free (D_FP) or the immobilized cells (D_IPC), for 4 weeks (109 cfu/day, in all groups). At the end of the dietary intervention, D_IPC group exerted lower concentration of the inflammatory cytokine IL-1b compared to D_FP. Consumption of immobilized on Corinthian currants P. acidilactici ORE5 cells by diabetic animals led to increased loads of fecal lactobacilli and lower levels of Enterobacteriaceae, coliforms, and E. coli, while Actinobacteria phylum, Akkermansia, and Bifidobacterium genera abundances were increased, and fecal lactic acid was elevated. Overall, the results of the present research demonstrated that functional ingredients can ameliorate gut dysbiosis present in T1D and could be used to design dietary patterns aiming at T1D management. However, well-designed clinical trials are necessary, in order to confirm the beneficial effects in humans.