This Gram positive coccus is most frequently found in pairs and short chains of spherical or ovoid cells. Cells are catalase negative and exhibit facultatively anaerobic metabolism. Optimum temperature for growth is 37 C, but has been grown at 45 C. This is the main organism responsible for the biofilm known as “plaque” that coats unbrushed teeth. Brushing and flossing mechanically removes the biofilm, which quickly reorganizes and grows to cover tooth surface again in a matter of hours. This microbe then acts as the major agent for forming dental caries (cavities) in humans. \u00a0<\/p>\n\n\n\n