IADR Abstract Archives

Antibacterial Effect Of Probiotic Lactobacillus casei Shirota Towards Streptococcus mutans

Background: Some probiotic lactobacilli have shown the antibacterial effect against oral pathogenic bacteria. However, potential probiotic effect of Lactobacillus casei Shirota, a strain from Yakult, on Streptococcus mutans remains unclear.

Objectives: This study aimed to evaluate the effect of L. casei Shirota on the growth of the important cariogenic bacteria S. mutans.

Materials and Methods: 2ml cell free culture supernatants from different growth phases of L. casei Shirota culture were added into 10ml S. mutans culture, then incubated in a 5% CO2 incubator for 8 hours. S. mutans growth curve was observed by spectrophotometry and bacteria counting. The effect of neutralized L. casei Shirota supernatant and autoclaved (121°C, 15min) supernatant on the growth of S. mutans were also evaluated by spectrophotometry. The inhibitory compound in L. casei Shirota supernatant was crudely extracted by ethyl acetate and the inhibition effect was determined by the agar well diffusion test.

Results: L. casei Shirota supernatant within and after stationary phase greatly inhibited the growth of S. mutans (P<0.01). Neutralized supernatant showed no inhibitory effect (P>0.05). Autoclaved supernatant remained the same antibacterial effect as the fresh supernatant (P>0.05). The ethyl acetate crude extract displayed the inhibition zone on S. mutans agar plate.

Conclusions: L. casei Shirota supernatant may produce antibacterial compound to inhibit the growth of S. mutans in oral biofilm. The antibacterial effect is pH-dependent and heat stable.

(This study was financially supported by Singapore MOE grant R-222-000-031-112)


Southeast Asian Division Meeting
2011 Southeast Asian Division Meeting (Singapore)
Singapore
2011
179
Scientific Groups
  • Chen, Huizhen  ( Department of Preventive Dentistry, Faculty of Dentistry, National University of Singapore, Singapore, N/A, Singapore )
  • Zhang, Lian Hui  ( Institute of Molecular and Cell Biology, Singapore, Singapore, N/A, Singapore )
  • Lee, Yuan Kun  ( Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, N/A, Singapore )
  • Hsu, Chin-ying, Stephen  ( National University of Singapore, Singapore, N/A, Singapore )
    • Poster Session
    Microbiology/Immunology II
    10/30/2011