Antimicrobial activity of Lactobacillus plantarum against oral microbial plaque

Abstract

Some strains of lactic acid bacteria have a favorable influence on physiologic and pathological processes of the host due to their specific health-promoting probiotic characteristics that relate to modulation of the immune system. The aim of the present study is to evaluate the possibility of antimicrobial substances against oral microbial plaque, extracted from Lactobacillus plantarum during its growth in broth culture media. 50 samples collected from white headed cabbage and kept in sterile tubes containing Man-Rogosa-Sharpe medium (MRS) broth were incubated for 3 days, and then subcultured on MRS agar. The grown colonies were characterized by phenotypical properties. Polymerase chain reaction (PCR) analyses were then performed on the extracted DNA from cultures. The colony of L. plantarum confirmed by PCR, were inoculated in MRS broth for 5 days and then mixed with ethyle acetate. The solution was separated into two phases, in which the supernatant comprised of the extracted antimicrobial compound. The supernatant was then dried at 45°C and was used for antimicrobial susceptibility by E. Test. The MIC's of this compound which affected target bacteria were as follow: Streptococcus mutans 0.1 mg/ml,Streptococcus salivarius 0.05 mg/ml, Streptococcus sanguis 0.2 mg/ml, and Lactobacillus casei 0.05 mg/ml. According to this study and others, L. plantarum can produce antimicrobial compounds and these bacteria exist in fresh vegetables; consumption of such vegetables may colonize this probiotic and other useful probiotics in the mouth and intestines and protect these parts of body from pathogens. Key words: Lactobacillus plantarum, oral plaque and antimicrobial.