Editing Streptococcus pyogenes (section)

{{Short description|Species of bacterium}}
{{Use mdy dates|date=April 2024}}
{{Speciesbox
| image = Streptococcus Pyogenes (Group A Strep) (52602981880).jpg
| image_caption = False-color scanning electron micrograph of chain of ''Streptococcus pyogenes'' bacteria (yellow)
| genus = Streptococcus
| species = pyogenes
| authority = Rosenbach 1884
| synonyms =
| synonyms_ref =
}}

'''''Streptococcus pyogenes''''' is a [[species]] of [[Gram-positive]], aerotolerant [[bacteria]] in the genus ''[[Streptococcus]]''.  These bacteria are [[extracellular]], and made up of non-motile and non-sporing [[cocci]] (round cells) that tend to link in chains. They are clinically important for humans, as they are an infrequent, but usually [[Pathogenic bacteria|pathogenic]], part of the [[skin microbiota]] that can cause [[group A streptococcal infection]].  ''S. pyogenes''  is the predominant species harboring the [[Lancefield grouping|Lancefield]] group A [[antigen]], and is often called '''group A ''Streptococcus''''' ('''GAS''').  However, both ''[[Streptococcus dysgalactiae]]'' and the ''[[Streptococcus anginosus]]'' group can possess group A antigen as well.  Group A streptococci, when grown on [[blood agar]], typically produce small (2–3&nbsp;mm) zones of [[beta-hemolysis]], a complete [[Lysis|destruction]] of [[red blood cell]]s. The name '''group A (beta-hemolytic) ''Streptococcus''''' is thus also used.<ref name=PSDS>{{cite web|url=http://www.phac-aspc.gc.ca/lab-bio/res/psds-ftss/strep-pyogenes-eng.php |title=Streptococcus pyogenes - Pathogen Safety Data Sheets |publisher=Government of Canada, Public Health Agency of Canada|date=September 26, 2001 }}</ref>

The species name is derived from Greek words meaning 'a chain' ({{lang|el-Latn|streptos}}) of berries ({{lang|la|coccus}} [Latinized from {{lang|el-Latn|kokkos}}]) and [[pus]] ({{lang|el-Latn|pyo}})-forming (''genes''), since a number of infections caused by the bacterium produce pus.  The main criterion for differentiation between ''[[Staphylococcus]]'' spp. and ''Streptococcus'' spp. is the [[catalase test]].  Staphylococci are catalase positive whereas streptococci are catalase-negative.<ref name=Sherris>{{cite book | veditors = Ryan KJ, Ray CG | title = Sherris Medical Microbiology | edition = 4th | publisher = McGraw Hill | year = 2004 | isbn = 978-0-8385-8529-0 }}</ref>  ''S. pyogenes'' can be [[microbiological culture|cultured]] on fresh blood agar plates. The [[Pyrrolidonyl-β-naphthylamide|PYR]] test allows for the differentiation of ''Streptococcus pyogenes'' from other morphologically similar beta-hemolytic streptococci (including ''S. dysgalactiae'' subsp. ''esquismilis'') as ''S. pyogenes'' will produce a positive test result.<ref>{{cite book| vauthors = Spellerberg B, Brandt C | chapter = Chapter 29: Laboratory Diagnosis of Streptococcus pyogenes (group A streptococci) |title=''Streptococcus pyogenes'': Basic Biology to Clinical Manifestations|date=October 9, 2022|orig-date=Originally published September 15, 2022| veditors = Ferretti JJ, Stevens DL, Fischetti VA|edition=2nd|publisher=University of Oklahoma Health Sciences Center|location=Oklahoma City, United States | chapter-url= https://www.ncbi.nlm.nih.gov/books/NBK587110/|access-date=May 11, 2023|via=National Center for Biotechnology Information, National Library of Medicine |pmid=36479747}}</ref>

An estimated 700 million GAS infections occur worldwide each year. While the overall mortality rate for these infections is less than 0.1%, over 650,000 of the cases are severe and invasive, and these cases have a mortality rate of 25%.<ref>{{cite journal | vauthors = Aziz RK, Kansal R, Aronow BJ, Taylor WL, Rowe SL, Kubal M, Chhatwal GS, Walker MJ, Kotb M | display-authors = 6 | title = Microevolution of group A streptococci in vivo: capturing regulatory networks engaged in sociomicrobiology, niche adaptation, and hypervirulence | journal = PLOS ONE | volume = 5 | issue = 4 | pages = e9798 | date = April 2010 | pmid = 20418946 | pmc = 2854683 | doi = 10.1371/journal.pone.0009798 | veditors = Ahmed N | doi-access = free | bibcode = 2010PLoSO...5.9798A }}</ref> Early recognition and treatment are critical; [[Medical diagnosis|diagnostic failure]] can result in [[sepsis]] and death.<ref name=NYT71112>{{cite news|title=An Infection, Unnoticed, Turns Unstoppable|url=https://www.nytimes.com/2012/07/12/nyregion/in-rory-stauntons-fight-for-his-life-signs-that-went-unheeded.html|access-date=July 12, 2012|newspaper=The New York Times|date=July 11, 2012|author=Jim Dwyer}}</ref><ref name=NYT71812>{{cite news|title=After Boy's Death, Hospital Alters Discharging Procedures|url=https://www.nytimes.com/2012/07/19/nyregion/after-rory-stauntons-death-hospital-alters-discharge-procedures.html|access-date=July 19, 2012|newspaper=The New York Times|date=July 18, 2012|author=Jim Dwyer}}</ref> ''S. pyogenes'' is clinically and historically significant as the cause of [[scarlet fever]], which results from exposure to the species' [[exotoxin]].<ref name="pmid29939666">{{Citation | vauthors = Pardo S, Perera TB | chapter = Scarlet Fever |date=2023 | chapter-url = http://www.ncbi.nlm.nih.gov/books/NBK507889/ | title = StatPearls |access-date=January 14, 2024 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=29939666 }}</ref>