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

Abstract

Objective: The 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. Methods: Strains 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. Results: Genotypic 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. Conclusions: LL 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.