Streptococcus mutans
Streptococcus mutans | |
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Gram stain of S. mutans in thioglycollate broth culture. | |
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Species: | S. mutans
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Streptococcus mutans Clarke 1924
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Streptococcus mutans is a Gram-positive, facultatively anaerobic bacteria commonly found in the human oral cavity and is a significant contributor to tooth decay.[1],[2]
Role in tooth decay
Along with S. sobrinus, S. mutans plays a major role in tooth decay, metabolizing sucrose to lactic acid.[2] The acidic environment created in the mouth by this process is what causes the highly mineralized tooth enamel to be vulnerable to decay. The microbe was first described by J. K. Clark in 1924. S. mutans is one of a few specialized organisms equipped with receptors for adhesion to the surface of teeth. Sucrose is utilized by S. mutans to produce a sticky, extracellular, dextran-based polysaccharide that allows them to cohere to each other forming plaque. S. mutans produces dextran via the enzyme dextransucrase using sucrose as a substrate in the following reaction:
n sucrose → (glucose)n + n fructose
Sucrose is the only sugar that S. mutans can use to form this polysaccharide.[1] Conversely, many sugars—glucose, fructose, lactose, sucrose—can be digested by S. mutans to produce lactic acid as an end product. It is the combination of plaque and acid that leads to dental decay.[3]
References
- ^ a b Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed. ed.). McGraw Hill. ISBN 0-8385-8529-9.
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has extra text (help)CS1 maint: multiple names: authors list (link) - ^ a b Loesche WJ (1996). Microbiology of Dental Decay and Periodontal Disease. In: Barron's Medical Microbiology (Barron S et al, eds.) (4th ed. ed.). Univ of Texas Medical Branch. (via NCBI Bookshelf) ISBN 0-9631172-1-1.
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has extra text (help) - ^ Madigan M; Martinko J (editors). (2005). Brock Biology of Microorganisms (11th ed. ed.). Prentice Hall. ISBN 0-13-144329-1.
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External links