Strep throat causes: Difference between revisions
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*Members of the normal flora | *Members of the normal flora | ||
*Human skin and mucous membrane only known reservoir | *Human skin and mucous membrane only known reservoir | ||
==Serovars== | |||
*More than 80 serotypes identified based on M protien | *More than 80 serotypes identified based on M protien | ||
*GAS strep throat may be associated with serotypes such as M types 1, 3, 5, 6, 14, 18, 19, and 24.<ref name="pmid2670192">{{cite journal| author=Fischetti VA| title=Streptococcal M protein: molecular design and biological behavior. | journal=Clin Microbiol Rev | year= 1989 | volume= 2 | issue= 3 | pages= 285-314 | pmid=2670192 | doi= | pmc=358122 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2670192 }} </ref><ref name="pmid10885988">{{cite journal| author=Cunningham MW| title=Pathogenesis of group A streptococcal infections. | journal=Clin Microbiol Rev | year= 2000 | volume= 13 | issue= 3 | pages= 470-511 | pmid=10885988 | doi= | pmc=88944 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10885988 }} </ref> | *GAS strep throat may be associated with serotypes such as M types 1, 3, 5, 6, 14, 18, 19, and 24.<ref name="pmid2670192">{{cite journal| author=Fischetti VA| title=Streptococcal M protein: molecular design and biological behavior. | journal=Clin Microbiol Rev | year= 1989 | volume= 2 | issue= 3 | pages= 285-314 | pmid=2670192 | doi= | pmc=358122 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2670192 }} </ref><ref name="pmid10885988">{{cite journal| author=Cunningham MW| title=Pathogenesis of group A streptococcal infections. | journal=Clin Microbiol Rev | year= 2000 | volume= 13 | issue= 3 | pages= 470-511 | pmid=10885988 | doi= | pmc=88944 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10885988 }} </ref> | ||
==Features of group A streptococcal infection== | |||
*[[Gram-positive]] coccus (grows in chains) | *[[Gram-positive]] coccus (grows in chains) | ||
*Non-motile | *Non-motile | ||
| Line 23: | Line 23: | ||
*Capsulated ([[hyaluronic acid capsule]]) | *Capsulated ([[hyaluronic acid capsule]]) | ||
==Classification of GAS== | |||
*According to the lancefield classification, based on the group A antigen in the [[cell wall]], it is named as group A streptococcus | *According to the lancefield classification, based on the group A antigen in the [[cell wall]], it is named as group A streptococcus | ||
*Based on the [[hemolysis]] on blood agar, the GAS is [[β-hemolytic]] (clear, complete lysis of red cells) | *Based on the [[hemolysis]] on blood agar, the GAS is [[β-hemolytic]] (clear, complete lysis of red cells) | ||
==Virulence factors== | |||
Virulence factors of group A streptococci include:<ref name="pmid20347595">{{cite journal| author=Smeesters PR, McMillan DJ, Sriprakash KS| title=The streptococcal M protein: a highly versatile molecule. | journal=Trends Microbiol | year= 2010 | volume= 18 | issue= 6 | pages= 275-82 | pmid=20347595 | doi=10.1016/j.tim.2010.02.007 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20347595 }} </ref><ref name="pmid16223875">{{cite journal| author=Mora M, Bensi G, Capo S, Falugi F, Zingaretti C, Manetti AG et al.| title=Group A Streptococcus produce pilus-like structures containing protective antigens and Lancefield T antigens. | journal=Proc Natl Acad Sci U S A | year= 2005 | volume= 102 | issue= 43 | pages= 15641-6 | pmid=16223875 | doi=10.1073/pnas.0507808102 | pmc=1253647 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16223875 }} </ref> | Virulence factors of group A streptococci include:<ref name="pmid20347595">{{cite journal| author=Smeesters PR, McMillan DJ, Sriprakash KS| title=The streptococcal M protein: a highly versatile molecule. | journal=Trends Microbiol | year= 2010 | volume= 18 | issue= 6 | pages= 275-82 | pmid=20347595 | doi=10.1016/j.tim.2010.02.007 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20347595 }} </ref><ref name="pmid16223875">{{cite journal| author=Mora M, Bensi G, Capo S, Falugi F, Zingaretti C, Manetti AG et al.| title=Group A Streptococcus produce pilus-like structures containing protective antigens and Lancefield T antigens. | journal=Proc Natl Acad Sci U S A | year= 2005 | volume= 102 | issue= 43 | pages= 15641-6 | pmid=16223875 | doi=10.1073/pnas.0507808102 | pmc=1253647 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16223875 }} </ref> | ||
*A hyaluronic acid capsule (outer most covering-inhibits phagocytosis) | *A hyaluronic acid capsule (outer most covering-inhibits phagocytosis) | ||
Revision as of 16:05, 20 October 2016
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Strep throat Microchapters |
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Strep throat causes On the Web |
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American Roentgen Ray Society Images of Strep throat causes |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Aysha Anwar, M.B.B.S[2]
Overview
Strep throat is caused by B hemolytic Group A streptococcal infection. More than 80 serotypes are identified based on M protien. GAS strep throat may be associated with serotypes such as M types 1, 3, 5, 6, 14, 18, 19, and 24.[1]
Causes
Strep throat is caused by B hemolytic Group A streptococcal infection.
Reservoir
- Members of the normal flora
- Human skin and mucous membrane only known reservoir
Serovars
- More than 80 serotypes identified based on M protien
- GAS strep throat may be associated with serotypes such as M types 1, 3, 5, 6, 14, 18, 19, and 24.[1][2]
Features of group A streptococcal infection
- Gram-positive coccus (grows in chains)
- Non-motile
- Non-spore forming
- 0.5-1.2µm in size
- Catalase-negative
- Facultative anaerobes or obligate (strict) anaerobes
- Requires enriched media (blood agar)to grow
- Capsulated (hyaluronic acid capsule)
Classification of GAS
- According to the lancefield classification, based on the group A antigen in the cell wall, it is named as group A streptococcus
- Based on the hemolysis on blood agar, the GAS is β-hemolytic (clear, complete lysis of red cells)
Virulence factors
Virulence factors of group A streptococci include:[3][4]
- A hyaluronic acid capsule (outer most covering-inhibits phagocytosis)
- Peptidoglycan cell wall
- Cell membrane
- Adhesion molecules
- M protein PMC358122
- Lipoteichoic acid (located in cell membrane)
- Extracellular components
- Toxins
- Pyrogenic (erythrogenic) toxin (rash of scarlet fever)
- Invasins
References
- ↑ 1.0 1.1 Fischetti VA (1989). "Streptococcal M protein: molecular design and biological behavior". Clin Microbiol Rev. 2 (3): 285–314. PMC 358122. PMID 2670192.
- ↑ Cunningham MW (2000). "Pathogenesis of group A streptococcal infections". Clin Microbiol Rev. 13 (3): 470–511. PMC 88944. PMID 10885988.
- ↑ Smeesters PR, McMillan DJ, Sriprakash KS (2010). "The streptococcal M protein: a highly versatile molecule". Trends Microbiol. 18 (6): 275–82. doi:10.1016/j.tim.2010.02.007. PMID 20347595.
- ↑ Mora M, Bensi G, Capo S, Falugi F, Zingaretti C, Manetti AG; et al. (2005). "Group A Streptococcus produce pilus-like structures containing protective antigens and Lancefield T antigens". Proc Natl Acad Sci U S A. 102 (43): 15641–6. doi:10.1073/pnas.0507808102. PMC 1253647. PMID 16223875.