In vitro investigation on the effects of oral lactic acidbacteria on biofilm and halitosis

Difficulties in the mechanical cleaning of oral biofilm in children and some side effects of the chemicals used for this purpose have highlighted probiotic therapy. The aim of this study was to determine the oral probiotics which have antiadhesion, antibiofilm activity and effects on halitosis. For this purpose, facultative anaerobic bacteria and yeast diversity of the samples taken from the biofilm areas on the tooth surfaces of healthy children were revealed. Bacteria were identified according to the 16S rRNA gene sequence and yeasts were biochemically identified by Vitek-2 system. Survival rates at gastrointestinal conditions, antibiotic susceptibility, antioxidant activity, aggregation activities, antimicrobial activity and biofilm forming properties of isolates which identified as Lactobacillus sp. were determined. Antiadhesion and antibiofilm activities of selected lactic acid bacteria on saliva coated hydroxyapatite discs were investigated. As a result of 16S rRNA sequence analysis, Firmicutes (83.4%) was the predominant phylum in the microbial composition and Lactobacillus was defined as the dominant strain. In this genus, L. rhamnosus, L. fermentum, L. paracasei, L. casei, L. plantarum ve L. salivarus species were identified. Neisseria in Proteobacteria phylum, Rothia in Actinobacteria phylum was identified as predominant genus. Candida dubliniensis was found to be the dominant species among yeast isolates. Lactic acid bacteria were found to be resistant to gastrointestinal conditions, showed antioxidant and aggregation activities and were biofilm producers. However, they did not have antimicrobial activity against selected oral microorganisms. Some selected lactic acid bacteria showed antiadhesion and antibiofilm activity. According to the results of organoleptic analysis, it was determined that L. rhamnosus LAB1.2.A could be effective on halitosis.