In Vitro antibacterial activity of Lactiplantibacillus sp. cell-free supernatants against Porphyromonas gingivalis: A potential approach for oral health

Objective

This study explores the potential of postbiotic metabolites from lactic acid bacteria (LAB) isolated from human milk and tempeh against Porphyromonas gingivalis, a key pathogen in periodontitis.

Design

Selected LAB strains and their treated cell-free supernatants (TCFS), lyophilized TCFS (L-TCFS), and bacteriocin-like inhibitory substances (BLIS) were tested individually and in combination using agar well diffusion, MIC, MBC, autoaggregation, coaggregation, and biofilm inhibition assays. LAB identification was performed using the API 50 CHL kit and 16S rDNA sequencing.

Results

Strain S2, a mixture of Lactiplantibacillus sp. SUK1 and T2 showed the highest inhibitory activity (20.06 ± 4.14 mm) using the agar well diffusion method. It demonstrated strong autoaggregation compared to the individual T2 strain but lacked significant coaggregation ability. The L-TCFS of S2 also exhibited the strongest antibacterial effect, with a minimum inhibitory concentration (MIC) of 50 mg/mL, although no minimum bactericidal concentration (MBC) was detected for any bacteriocin-like inhibitory substances (BLIS). L-TCFS from strain S2 significantly reduced P. gingivalis biofilm formation at a minimum concentration of 25 mg/mL, compared to the untreated control. Strain T2 was identified as Lactiplantibacillus plantarum using the API 50CHL test and 16S rDNA gene sequencing.

Conclusion

The combination metabolite S2 demonstrates promising inhibitory activity against P. gingivalis and may serve as an effective adjunctive therapy for periodontal infections, outperforming individual and other combination LAB strains tested.