IADR Abstract Archives
Evaluation of Antimicrobial Effect of Lactobacillus Reuteri on Streptococcus Mutans
Objectives: The aim of this study was to evaluate “in vitro” the antimicrobial effect of probiotic Lactobacillus reuteri-55730 on Streptococcus mutans-UA130 counts by the Kirby Bauer Method and Minimum Inhibitory Concentration techniques.
Methods: For the Kirby Bauer Method, Petri dishes were inoculated with S. mutans, subsequently diffusion disk was soaked with L. reuteri and placed in the dishes; positive (Chlorhexidine 0.12%) and negative (distilled water) controls were used also. The interpretation of the results is based on the size of the halo and bacterial growth.
After having a suitable concentration of S. mutans and L. reuteri done by measuring the absorbance (600nm), the Minimum Inhibitory Concentration (MIC) was carried out. Each tube had 1ml of final volume, which consisted in Brain-Heart Infusion medium of S. mutans, consecutively the indicated concentration obtained from different growth phases of L. reuteri (10,12,14,16,18 and 20 hours), and finally S. mutans strain.
Both procedures were performed in triplicate. We also used E. coli as bacterial control.
Results: Results on both techniques showed that L. reuteri has the ability to interrupt the growth of S. mutans at 16 hours of growth. Antibiogram halos showed sizes of 4.3mm compared to 3.2mm of Chlorexidine. In MIC technique, we obtained high values of absorbance because the two bacteria were together nevertheless we observed by microscopy an increased in cellular concentration of L. reuteri and an inhibitory effect of S. mutans and E. coli growth.
Conclusions: L. reuteri can reduce S. mutans levels in vitro, it has a good performance as an antimicrobial agent and has more efficiency in its exponential phase of growth. It means that L. reuteri can be used to reduce cariogenic microorganisms like S. mutans and approach to caries prevention. Further research is needed to use L. reuteri as an alternative strategy in oral health.
Methods: For the Kirby Bauer Method, Petri dishes were inoculated with S. mutans, subsequently diffusion disk was soaked with L. reuteri and placed in the dishes; positive (Chlorhexidine 0.12%) and negative (distilled water) controls were used also. The interpretation of the results is based on the size of the halo and bacterial growth.
After having a suitable concentration of S. mutans and L. reuteri done by measuring the absorbance (600nm), the Minimum Inhibitory Concentration (MIC) was carried out. Each tube had 1ml of final volume, which consisted in Brain-Heart Infusion medium of S. mutans, consecutively the indicated concentration obtained from different growth phases of L. reuteri (10,12,14,16,18 and 20 hours), and finally S. mutans strain.
Both procedures were performed in triplicate. We also used E. coli as bacterial control.
Results: Results on both techniques showed that L. reuteri has the ability to interrupt the growth of S. mutans at 16 hours of growth. Antibiogram halos showed sizes of 4.3mm compared to 3.2mm of Chlorexidine. In MIC technique, we obtained high values of absorbance because the two bacteria were together nevertheless we observed by microscopy an increased in cellular concentration of L. reuteri and an inhibitory effect of S. mutans and E. coli growth.
Conclusions: L. reuteri can reduce S. mutans levels in vitro, it has a good performance as an antimicrobial agent and has more efficiency in its exponential phase of growth. It means that L. reuteri can be used to reduce cariogenic microorganisms like S. mutans and approach to caries prevention. Further research is needed to use L. reuteri as an alternative strategy in oral health.
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