Probiotic Lactobacillus Salivarius Strains’ Screening And A Primary Research Of Its Antibiotics And Adhesive Action

Objectives: This study aimed to screen the probiotic potential of Lactobacillus salivarius strain from oral cavity of healthy volunteers, and to investigate its probiotic properties against oral diseases for providing a preliminary strategy.Methods:(1) Selecting Volunteers that healthy and have not any oral disease, then gathering their unstimulated saliva to selective culture using the LBS solid medium. Selecting the withe and different size circular bacterial colonies to monoclonal cultivate. Lactobacillus salivarius are selected by the Lactobacillus strains’ Gram staining and 16 srDNA sequencing and BLAST in NCBI. Moreover, Lactobacillus salivarius strains are cutruled by liquid MRS medium and gathering their fermentation supernatant by high speed Centrifugation and filtration. Using fermentation supernatant to inhibit the streptococcus mutans(SM) and selecting the aim strains which have the significant ability of bacteriostasis.(2) Gathering the aim strain’s fermentation supernatant and detect bactericidal substance’s effect of bacteriostasis in different concentration. We also should detecte its stability to temperature, the sensitivity to protease, and broad-spectrum antibacterial ability.(3) The aim strains and SM UA159 are co-cultured upon the cover glass by different concentration. Using the light microscope and scanning electron microscope(SEM) to observe their adhesive ability in vitro. Results: 1. We have Selected the 4 Lactobacillus salivarius strains that have different genotype and find they have different bacteriostatic ability for SM UA159. One strain is determined the targeted species which have a significant effect of inhibiting SM UA159 and named w22 a. 2.(1) Bacteriostatic ability is not obvious when the w22a’s sterile fermented supernatant diluted 1/3 as stoste. The diameter of inhibition zone have no significant differences compared with controlled group(P>0.05). But The effect of inhibiting streptococci mutans showed an increasing trends with the antibacterial substance’s concentration.(2) The w22a’s sterile fermented supernatant is treated by different temperature between 60℃ to 90℃ and it’s ability of inhibit SM UA159 have no influence, there are no significant differences between each groups(P>0.05).(3) The w22a’s sterile fermented supernatant is treated by catalase and other broad-spectrum proteases and it’s ability of inhibit SM UA159 have a significant destroying. The effect of Proteinase K is more significant.(4) The w22a’s sterile fermented supernatant also have different effect of inhibiting Staphylococcus aureus(MRSA)ATCC25923 、 Candida Albicans(Ca)ATCC10231 、 Lactobacillus acidophilus(La) ATCC4356 and Escherichia coli DH5α. 3. Compared with SM UA159, w22 a have more ability to adhere the oral hard tissue model in vitro. It’s also can influence the growth of SM UA159 when its concentration reach a specific quantity. Conclusions: The w22 a of Lactobacillus salivarius strain have a potential of probiotic properties in oral cavity, and this finding provide a well research value and applied foreground.