Environmental Factors Influence Biofilm Formation Of Streptococcus Oligofermants And Strepcococcsu Mutans When Grown In Dual-species Mode

Objectives:To observe the environmental factors influence biofilm formation of Streptococcus oligofermants (So)and Streptococcus mutans (Sm)when grown in dual-species mode,and compare with Streptococcus. sanguinis.(Ss),in order to discuss the function of So in maintain the balance of oral environment.Methods:1Human Saliva Preparation. Whole saliva samples were collected from three healthy human. The saliva was centrifuged and10000×g for20min at4℃. The samples were sterilized using a sterile membrane filter(0.22μm) and used immediately for the biofilm formation assay.2The establishment of the model of saliva coated①The establishment of polystyrene:96-well microtiter plate coating with saliva for30min at37℃.②he establishment of glass:glass tube coating with saliva for30min at37℃.3The establishment of single、dual-species modelSingle-species:So、Ss、SmDual-species;So and Sm,Ss and Sm.4To investigate the interaction between different bacterial in single-species or dual-species of different environment factors①To observe the adhesion of different bacterial in single-species or dual-species on the glass by microbiological methods.②To observe the adhesion of different bacterial in single-species or dual-species on the polystyrene by safranin methods.5To obserbe the thickness of biofilm in single-species or dual-species in different sucrose concentration by confocal laser scanning microscope.Results:1The influence of oxygen factors on the interaction of bacterial in dual-speciesBiofilm formation by Sm was decreased when grown with Ss and So under different oxygen factors, but was significantly decreased when it grown under aerobic condition. And biofilm formation by Sm was decreased obviously when it co-cultivated with So under aerobic condition or anaerobic conditions.2The influence of different sucrose factors on the interaction of bacterial in dual-speciesBiofilm formation by Sm was decreased when grown with Ss and So under different sucrose factors. And the two probiotics show different ability of inhibition: the ability of So of inhibition:1%>0%>5%, but the ability of Ss of inhibition:0%>l%>5%.The biofilm formation of Sm was decreased obviously when it co-cultivated with S.oligofermants under1%and5%sucrose conditions.3The influence of different pH factors on the interaction of bacterial in dual-speciesBiofilm formation by Sm was decreased when grown with Ss and So under pH6.0、pH6.5、pH7.0and pH7.5, pH7.0>pH6.5> pH6.0and pH7.5(There is no significant differences between pH6.0and pH7.5), and no matter of any pH condition, biofilm formation of Sm was decreased significantly when it co-cultivated with So. But there is no changes of biofilm formation by Sm when it grown under pH5.5and pH8.0.4The thickness of biofilm in single-species or dual-species in different sucrose concentration by confocal laser scanning microscopeThe biofilm thickness of the three bacterial under0%sucrose:Ss> S m>So; under1%sucrose:Sm> Ss>So. The thickness of biofilm of dual-species were reduced.Conclusions:1The inhibition of Sm by So was stronger than Ss under both oxygen conditions, and the inhibition were weaker under anaerobic conditions.2The inhibition of Sm by So was stronger than Ss under1%and5%sucrose concentration, and the ability of Ss of inhibiton was stronger than So under0%sucrose concentration. 3The inhibition of Sm by So was stronger than Ss under pH6.0, pH6.5,pH7.0and pH7.5, and the inhibition was strongest under pH7.0,then is pH6.5, pH6.0and pH7.5were weakest (p>0.05).So and Ss only maintain their growth but not show any inhibition on Sm under pH5.5and pH8.0.4The environmental factors can influence the the inhibition of So and Ss, and So shows more inhibition ability than S. sanguinis under all different condition.