| Objective:Through in vitro culture Streptococcus mutans (Sm). Actinobacillus actinomycetemcomitans (Aa), Fusobacterium nucleatum (Fn), this study investigate the effects of the liquid of Sm cultured, medium supernatant and liquid of Sm cell inactivation crushed to the growth of Aa and Fn. And whether there is ability of Sm to inhibit Aa and Fn adhesion to SLA titanium plate.Method Experiment1:The stain of Sm, Aa and Fn have been revived, then proliferated. Through colony observation, biochemical identification and Gram staining observing, it ensures that the proliferation of bacteria strains is purposed strain. And then:1Compound the concentration of1×108CFU/ml of Sm, Fn, Aa bacteria suspension;2Collect Sm bacterial culture supernatant, bacteria smash fluid;3Produce Live bacteria BH1agar plate of Sm, Aa and Fn, dug four holes in the plate. According to the Sabine antimicrobial test methods, antibacterial test has been done. After48hours cultured, diameter of inhibition zone has been measured.Experiment2:Titanium plates are blasted and acid, then the surface morphology of them are observed by electron microscopy. Each medium plate4titanium plate, then the experimental group1and experimental group2were respectively added1×108CFU/ml concentrations of Sm and Aa bacterial suspension, Sm and Fn bacterial suspension; the control group land the control group2were respectively added the same concentrations of Aa bacterial suspension, Fn bacterial suspension. At Oh,12h,24h,36h,48h,60h,72h,96h, the bacteria multiplication were assayed by means of Methyl thiazolyl tertrazolium (MTT) to draw the curve of vitality of bacteria. When the means of MTT measured vitality of bacteria, it groups Blank control group(PBS). BHI group, the experimental group1, the control groupl, the experimental group2, the control group2. Electron microscope was used to scan the titanium plates of the time point of60h to observe the member of bacteria, which adhered to titanium plates. Taking the four groups of time points60h titanium plate, each of them has been cleaned by PBS to remove disadhered bacteria, and then they was throuthly cleared with10ml PBS by hyperacoustic instrument. Then the PBS, with bacteria, was diluted l×105times. The100μl PBS was absorbed and Coated to the BHI agar surface. After48hours culture, the colony, on the BHI plate surface, was been count.Result Experiment1:After37℃anaerobic cultured for48h, Inhibition zone diameter of the Sm, on the Aa and Fn vital bacterial plate, was much larger in the Sm bacterial suspension fluid(1×108CFU/ml) groups than that in the PBS groups. And the difference was statistically significant(P<0.05); But, There wasn't significant difference, Inhibition zone diameter, on the Sm vital bacterial plate, in the Aa bacterial suspension fluid (1×108CFU/ml) groups and Fn bacterial suspension fluid (1×108CFU/ml) groups between the control group(P>0.05); After37℃anaerobic cultured for48h, there wasn't significant difference, Inhibition zone diameter, on the Aa and Fn vital bacterial plate, in the Sm bacterial culture supernatant groups and Sm bacteria smash fluid groups between the control groups(P>0.05).Experiment2:The curve of of bacteria vitality show that:the bacterial vitality of the control groupland the control group2was continued growth; before36hour, the bacterial vitality of the experimental group1and the experimental group2was continued growth;36h later, the bacterial vitality of the experimental group1and experimental group2began reduce.the bacterial vitality of the experimental group1was lower than the control group1, between36hour to96hour, and the difference was statistically significant(P<0.05); the bacterial vitality of the experimental group2was lower then the control group2, between36hour to96hour, and the difference was statistically significant(P<0.05). By the Electron microscope scanned, the amount of bacteria adhered to the SLA titanium plates of the experimental group were obviously less than that of the control group2. It is same to the experimental group2and the experimental group1. Micro-organisms of titanium plates'surface cultured for48hours, and then colonies were counted. The number of of the experimental group1and the experimental group2colonies were obvious less than that of the control group1and the control group2, the difference was statistically significant (P<0.05).Conclusion:1It is obviously that Sm bacterial suspension fluid(1×108CFU/ml) can inhibit the growth of Aa and Fn;2Sm bacterial culture supernatant and Sm bacteria smash fluid can't inhibit the growth of Aa and Fn;3Aa and Fn suspension fluids (1×108CFU/ml) can't Inhibit the growth of Sm;4Antibacterial substances of sm need to keep metabolism to produce;5after Sm and Aa and Sm and Fn mixed culture36h, Sm begen inhibit viability and proliferation of Aa and Fn;6Sm bacterial suspension fluids (1×108CFU/ml) can inhibit Aa and Fn adhesion to the SLA titanium plates;... |
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