Streptococcus mutans is a bacterium that participates in the normal flora of the human body. S.mutans can be found in the oral cavity, and researchers are now finding the bacteria in heart valves. The bacteria prefer human body temperatures but need an acidic place to live. Make interesting S. mutans and bacteria to study. Streptococcus mutans is a coconut-shaped, gram-positive bacterium. It is a facultative anaerobe. Streptococcus mutans is found in the oral cavity and can now be found in heart tissue and valves. Considering the fact that Streptococcus mutans is a facultative anaerobe, the bacteria are often found between the teeth, around the gum line and on occlusal surfaces. Streptococcus mutans lives at temperatures ranging from eighteen to forty degrees Celsius, falling into the mesophilic category. Streptococcus mutans changes the environment by adhering to a layer of biofilm produced on the surface of tooth enamel by things such as: acidic foods that contain sugars and starch, drinks that contain carbonation and sugars, whiting products, tobacco use and lack of oral home care. The first virulence factor depends on the synthesis of water-soluble glycans from the disaccharide sucrose. By breaking down glycogen this helps the bacteria stick together better. The next virulence factor, Streptococcus mutans, has the ability to become more acid resistant and communicate cell to cell. Once bacteria are colonized in the biofilm, they begin to produce an acidic environment below a pH of 7. (Kreth, et al., 2008). In this way, Streptococcus mutans competes with any other organism that lives on the teeth or in the oral cavity. This leads to the third factor, which shows lactic acid production from… middle of paper… controlled oral hygiene procedures on tooth decay and periodontal disease in adults. Journal of Clinical Periodontology, 5: 133–151. doi: 10.1111/j.1600-051X.1978.tb01914.xCharacterization of a glutamate transporter operon, glnQHMP, in Streptococcus mutans and its role in acid tolerance J. Bacteriol. February 2010 192:4 984-993Kreth, Jens, Yongshu Zhang, and Mark C. Herzberg. "Streptococcal antagonism in oral biofilms: interference of Streptococcus sanguinis and Streptococcus gordonii with Streptococcus mutans". Journal of bacteriology 190.13 (2008): 4632-4640.Loesche, Walter J. “Role of Streptococcus mutans in human dental caries.” Microbiological Reviews 50.4 (1986): 353.Cobessi, David, et al. “Apo and hol crystal structures of an NADP-dependent aldehyde dehydrogenase from<i>Streptococcus mutans.” Journal of Molecular Biology 290.1 (1999): 161-173.