Characterization of Lactococcus lactis subspecies lactis strain Y-PDH01-07 isolated from traditional Indonesian fermented milk (dadih) as an oral probiotic candidate.

ObjectiveThe balance of oral microbiota is important in oral disease prevention and treatment. Oral microbiomes play an essential role in oral diseases through anti-inflammatory effects and restoring dysbiosis. Lactococcus lactis subspecies lactis strains Y-PDH01-07 (LL01-07) were identified from dadih, a traditional Indonesian fermented milk. Previous research had shown that dadih can reduce colon inflammation. However, the characteristics of LL01-07 as an oral probiotic have not been explored. The objective of this research is to characterize and functionally assess the potential of LL01-07 as an oral probiotic.MethodsStrains were identified using phenotypic features, PCR, and sequencing, and their biosafety status was evaluated. The oral probiotic characterization of LL01-07 consisted of carbohydrate fermentation ability, antimicrobial activity, auto-aggregation, hydrophobicity, and acid resistance. An in vivo experiment was conducted to evaluate its anti-inflammatory effect on the oral mucosal wound model with unpaired t-test to evaluate the group's significance.ResultsGenotypic results confirmed that all isolates were Lactococcus lactis subsp. lactis, and biosafety assessment showed no inhibition zone in antibiotic resistance test and no hemolytic activity. LL05 had the highest % auto aggregation: 15.0 ± 1.7% at 33 h and 54.2 ± 4.8% at 22 h. LL05 had the best acid resistance test (75.2% survival after 4 h of acid exposure). The lesion severity score did not improve in the treatment group, but body weight increased.ConclusionsLL 01-07 was safe to administer to oral cavity but showed less oral probiotic potential. The in vivo study showed that the treatment group had a lower wound healing effect score but a higher average body weight.