Title Lipoteichoic acids of lactobacilli inhibit Enterococcus faecalis biofilm formation and disrupt the preformed biofilm
Author Solmin Jung1, Ok-Jin Park1, A Reum Kim1, Ki Bum Ahn1,2, Dongwook Lee1, Kee-Yeon Kum3, Cheol-Heui Yun4,5, and Seung Hyun Han1*
Address 1Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul 08826, Republic of Korea, 2Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup 56212, Republic of Korea, 3Department of Conservative Dentistry, DRI, and Seoul Dental Hospital for Disabled, School of Dentistry, Seoul National University, Seoul 03080, Republic of Korea, 4Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea, 5Institute of Green Bio Science Technology, Seoul National University, Pyeongchang 25354, Republic of Korea
Bibliography Journal of Microbiology, 57(4),310–315, 2019,
DOI 10.1007/s12275-019-8538-4
Key Words biofilm, Enterococcus faecalis, lipoteichoic acid, lactobacilli, apical periodontitis
Abstract Enterococcus faecalis, a Gram-positive bacterium commonly isolated in patients with refractory apical periodontitis, invades dentin tubules easily and forms biofilms. Bacteria in biofilms, which contribute to recurrent and/or chronic inflammatory diseases, are more resistant to antimicrobial agents than planktonic cells and easily avoid phagocytosis. Although Lactobacillus plantarum lipoteichoic acid (Lp.LTA) is associated with biofilm formation, the effect of Lp.LTA on biofilm formation by E. faecalis is not clearly understood. In this study, we investigated whether Lp.LTA inhibits E. faecalis biofilm formation. The degree of biofilm formation was determined by using crystal violet assay and LIVE/DEAD bacteria staining. The quantification of bacterial growth was determined by measuring the optical density at 600 nm with a spectrophotometer. Formation of biofilms on human dentin slices was observed under a scanning electron microscope. E. faecalis biofilm formation was reduced by Lp.LTA treatment in a dose-dependent manner. Lp.LTA inhibited biofilm development of E. faecalis at the early stage without affecting bacterial growth. LTA from other Lactobacillus species such as Lactobacillus acidophilus, Lactobacillus casei, or Lactobacillus rhamnosus GG also inhibited E. faecalis biofilm formation. In particular, among LTAs from various lactobacilli, Lp.LTA showed the highest inhibitory effect on biofilms formed by E. faecalis. Interestingly, LTAs from lactobacilli could remove the biofilm preformed by E. faecalis. These inhibitory effects were also observed on the surface of human dentin slices. In conclusion, Lactobacillus species LTA inhibits biofilm formation caused by E. faecalis and it could be used as an anti-biofilm agent for prevention or treatment against E. faecalis-associated diseases.