Streptococcus mutans

Streptococcus mutans
	Streptococcus mutans (Gram stain)
Systematics
Department :	Firmicutes
Class :	Bacilli
Order :	Lactobacillales
Family :	Streptococcaceae
Genre :	Streptococcus
Type :	Streptococcus mutans
Scientific name
	Streptococcus mutans
	Clarke 1924

Streptococcus mutans is a type of bacteria from the genus streptococci ( Streptococcus ). S. mutans is the leading organism of dental caries and ispresentin the saliva of almost everyone. The level of the concentration of S. mutans in the saliva correlates closely with the risk of caries.

description

S. mutans has roughly spherical to egg-shaped cells (“cocci”) that are arranged in pairs or in chains and do not move actively. The bacterium is gram-positive , facultatively anaerobic , has oxidative and fermentative energy metabolism and does not form spores . On gel culture media with complex nutrients, S. mutans forms rounded, convex colonies with a granulated surface. Most of the strains have an α- hemolytic effect (greenish discoloration around the bacteria on a blood-containing nutrient medium). However, β-hemolysis (complete dissolution of the erythrocytes and breakdown of hemoglobin ) was also detected in three strains .

Pathophysiology

Streptococcus mutans is the most important cause of tooth decay. The pathogen has a number of special properties ( virulence factors ) that assign it a major role in the formation of bacterial plaque :

Glucan-mediated adherence: S. mutans forms extracellular glucans from the sucrose contained in the chyme , with which the bacteria are able to adhere to the tooth enamel . So a biofilm is formed on the surfaces of the teeth . The formation of glucans is mediated by glucosyltransferases (enzymes for the transfer of glucose units). The activity of the glucosyltransferases is the benchmark for the virulence of the pathogen.

Lactic acid production: S. mutans breaks down carbohydrates into lactic acid (lactate) in the course of a fermentative energy metabolism . The resulting drop in pH leads to demineralization of the tooth substance.

Acid tolerance: Through the active excretion of protons , S. mutans is able to survive even in a strongly acidic environment.

Individual evidence

^ Clarke, J. Kilian (1924). On the Bacterial Factor in the Etiology of Dental Caries . British Journal of Experimental Pathology 5: 141-7. PMC 2047899 (free full text).
↑ A Sharma et al. (2009): Dermatoglyphic interpretation of dental caries and its correlation to salivary bacteria interactions: An in vivo study In: JISPPD , Vol. 27, No. 1, pp. 17-21 PMID 19414969 doi : 10.4103 / 0970-4388.50811
↑ Richard R. Facklam et al. (1977): Physiological Differentiation of Viridans Streptococci In: JCM , Vol. 5, No. 2, pp. 184-201 PMID 845245
↑ Larry Wolff et al. (1978): Observation of Beta-Hemolysis Among Three Strains of Streptococcus mutans In: IAI , Vol. 19, No. 2, pp. 745-748 PMID 24591
↑ ^a ^b ^c Friedrich Burkhardt : Microbiological diagnostics. Bacteriology, mycology, virology, parasitology . Thieme, 2009, ISBN 978-3-13-743602-7 , p. 323 .

[1] Clarke, J. Kilian (1924). On the Bacterial Factor in the Etiology of Dental Caries . British Journal of Experimental Pathology 5: 141-7. PMC 2047899 (free full text).

[2] A Sharma et al. (2009): Dermatoglyphic interpretation of dental caries and its correlation to salivary bacteria interactions: An in vivo study In: JISPPD , Vol. 27, No. 1, pp. 17-21 PMID 19414969 doi : 10.4103 / 0970-4388.50811

[3] Richard R. Facklam et al. (1977): Physiological Differentiation of Viridans Streptococci In: JCM , Vol. 5, No. 2, pp. 184-201 PMID 845245

[4] Larry Wolff et al. (1978): Observation of Beta-Hemolysis Among Three Strains of Streptococcus mutans In: IAI , Vol. 19, No. 2, pp. 745-748 PMID 24591

[Mikrobiologische-Diagnostik-5] Friedrich Burkhardt : Microbiological diagnostics. Bacteriology, mycology, virology, parasitology . Thieme, 2009, ISBN 978-3-13-743602-7 , p. 323 .