Comparison of growth of viable oral bacteria and Streptococcus mutans in biofilm models using three different culture media

Abstract

Traditional culture-based media can have different ability to recover mutans streptococci from pure culture and oral bacteria from saliva samples after biofilm formation. For this purpose, the aim of this study was to compare three different culture media: Brain heart infusion (BHI), ultrapurified tryptone-yeast extract broth (UTYEB) and defined medium mucin (DMM), in two biofilm models: microcosm and monoculture, over 72 and 96 h incubation periods. Ninety-six bovine teeth were used for each biofilm assay. These specimens were randomly assigned to six different groups (n=8). Fresh stimulated saliva and Streptococcus mutans UA159 were used for comparisons among different culture media in microcosms and monoculture assays, respectively. Biofilm was formed on enamel disks for 72 and 96 h and after that, the biomass was collected. The UTYEB was similar to DMM, but significantly different from BHI for bacterial growth in microcosm biofilm. For the monoculture biofilm, DMM was statistically different from BHI and UTYEB. It was concluded that UYTEB is a suitable alternative for microcosm and monoculture assays. Key words: Brain heart infusion (BHI), ultrapurified tryptone-yeast extract broth (UTYEB), defined medium mucin (DMM), dental plaque microcosm, monoculture.