Editing Streptococcus pyogenes (section)

== Disease ==
{{See also|Group A streptococcal infection}}

''S. pyogenes'' is the cause of many human diseases, ranging from mild superficial skin infections to life-threatening systemic diseases.<ref name=Sherris/> The most frequent manifestations of disease are commonly known as [[scarlet fever]]. Infections typically begin in the throat or skin. The most striking sign is a strawberry-like rash. Examples of mild ''S. pyogenes'' infections include [[Streptococcal pharyngitis|pharyngitis]] (strep throat) and localized skin infection ([[impetigo]]). [[Erysipelas]] and [[cellulitis]] are characterized by multiplication and lateral spread of ''S. pyogenes'' in deep layers of the skin. ''S. pyogenes'' invasion and multiplication in the [[fascia]] beneath the skin can lead to [[necrotizing fasciitis]], a life-threatening surgical emergency.<ref>{{cite journal | vauthors = Schroeder JL, Steinke EE | title = Necrotizing fasciitis--the importance of early diagnosis and debridement | journal = AORN Journal | volume = 82 | issue = 6 | pages = 1031–1040 | date = December 2005 | pmid = 16478083 | doi = 10.1016/s0001-2092(06)60255-x }}</ref><ref>
{{cite web |url=https://www.cdc.gov/Features/NecrotizingFasciitis/
 |title=Necrotizing Fasciitis |author=<!--Not stated--> |date=October 26, 2017 |website=CDC |publisher=Content source: National Center for Immunization and Respiratory Diseases, Division of Bacterial Diseases. Page maintained by: Office of the Associate Director for Communication, Digital Media Branch, Division of Public Affairs |access-date=January 6, 2018  }}
</ref> The bacterium is also an important cause of [[neonatal infection|infection in newborn]]s, who are susceptible to some forms of the infection that are rarely seen in adults, including [[meningitis]].<ref name="BaucellsMercadal Hally2015">{{cite journal | vauthors = Baucells BJ, Mercadal Hally M, Álvarez Sánchez AT, Figueras Aloy J | title = Asociaciones de probióticos para la prevención de la enterocolitis necrosante y la reducción de la sepsis tardía y la mortalidad neonatal en recién nacidos pretérmino de menos de 1.500g: una revisión sistemática | trans-title = Probiotic associations in the prevention of necrotising enterocolitis and the reduction of late-onset sepsis and neonatal mortality in preterm infants under 1,500g: A systematic review | journal = Anales de Pediatria | language = Spanish | volume = 85 | issue = 5 | pages = 247–255 | date = November 2016 | pmid = 26611880 | doi = 10.1016/j.anpedi.2015.07.038 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Berner R, Herdeg S, Gordjani N, Brandis M | title = Streptococcus pyogenes meningitis: report of a case and review of the literature | journal = European Journal of Pediatrics | volume = 159 | issue = 7 | pages = 527–529 | date = July 2000 | doi = 10.1007/s004310051325 | pmid = 10923229 | s2cid = 7693087 }}</ref>

Like many pathogenic bacteria, ''S. pyogenes'' may colonize a healthy person's respiratory system without causing disease, existing as a [[commensal]] member of the respiratory microbiota. It is commonly found in some populations as part of the mixed [[Human microbiome|microbiome]] of the upper respiratory tract. Individuals who have the bacterium in their bodies but no signs of disease are known as [[asymptomatic carrier]]s.<ref name="pmid38360357">{{cite journal |vauthors=Hung TY, Phuong LK, Grobler A, Tong SY, Freeth P, Pelenda A, Gibney KB, Steer AC |title=Antibiotics to eradicate Streptococcus pyogenes pharyngeal carriage in asymptomatic children and adults: A systematic review |journal=J Infect |volume=88 |issue=3 |pages=106104 |date=March 2024 |pmid=38360357 |doi=10.1016/j.jinf.2024.01.003 |url=|doi-access=free }}</ref><ref name="pmid31200755"/><ref name="pmid29554121"/> The bacteria may start to cause disease when the host's immune system weakens, such as during a viral respiratory infection, which may lead to ''S. pyogenes'' [[superinfection]].<ref name="pmid31200755">{{cite journal | vauthors = Othman AM, Assayaghi RM, Al-Shami HZ, Saif-Ali R | title = Asymptomatic carriage of Streptococcus pyogenes among school children in Sana'a city, Yemen | journal = BMC Research Notes | volume = 12 | issue = 1 | pages = 339 | date = June 2019 | pmid = 31200755 | pmc = 6570875 | doi = 10.1186/s13104-019-4370-5 | doi-access = free }}</ref><ref name="pmid29554121">{{cite journal | vauthors = Oliver J, Malliya Wadu E, Pierse N, Moreland NJ, Williamson DA, Baker MG | title = Group A Streptococcus pharyngitis and pharyngeal carriage: A meta-analysis | journal = PLOS Neglected Tropical Diseases | volume = 12 | issue = 3 | pages = e0006335 | date = March 2018 | pmid = 29554121 | pmc = 5875889 | doi = 10.1371/journal.pntd.0006335 | doi-access = free }}</ref>

''S. pyogenes'' infections are commonly associated with the release of one or more bacterial [[toxin]]s. The release of endotoxins from throat infections has been linked to the development of scarlet fever.<ref name="pmid29939666" /> Other toxins produced by ''S. pyogenes'' may lead to streptococcal [[toxic shock syndrome]], a life-threatening emergency.<ref name=Sherris/>

''S. pyogenes'' can also cause disease in the form of post-infectious "non-pyogenic" (not associated with local bacterial multiplication and pus formation) syndromes. These [[autoimmune]]-mediated complications follow a small percentage of infections and include [[rheumatic fever]] and acute [[post-infectious glomerulonephritis]]. Both conditions appear several weeks following the initial streptococcal infection. Rheumatic fever is characterized by inflammation of the joints and/or heart following an episode of [[streptococcal pharyngitis]]. Acute glomerulonephritis, inflammation of the [[renal glomerulus]], can follow streptococcal pharyngitis or skin infection.{{citation needed|date=February 2023}}

''S. pyogenes'' is sensitive to [[penicillin]], and has not developed [[Antimicrobial resistance|resistance]] to it,<ref>{{Cite journal |last=Horn |first=D. L. |last2=Zabriskie |first2=J. B. |last3=Austrian |first3=R. |last4=Cleary |first4=P. P. |last5=Ferretti |first5=J. J. |last6=Fischetti |first6=V. A. |last7=Gotschlich |first7=E. |last8=Kaplan |first8=E. L. |last9=McCarty |first9=M. |last10=Opal |first10=S. M. |last11=Roberts |first11=R. B. |last12=Tomasz |first12=A. |last13=Wachtfogel |first13=Y. |date=June 1998 |title=Why have group A streptococci remained susceptible to penicillin? Report on a symposium |url=https://pubmed.ncbi.nlm.nih.gov/9636860/ |journal=Clinical Infectious Diseases|volume=26 |issue=6 |pages=1341–1345 |doi=10.1086/516375 |issn=1058-4838 |pmid=9636860}}</ref> making penicillin a suitable [[antibiotic]] to treat infections caused by this bacterium. Failure of treatment with penicillin is generally attributed to other local commensal microorganisms producing [[β-lactamase]], or failure to achieve adequate tissue levels in the pharynx. Certain strains have developed resistance to [[macrolides]], [[tetracyclines]], and [[clindamycin]].<ref>{{cite journal |author = Tadesse, Molla |title = Prevalence, Antibiotic Susceptibility Profile and Associated Factors of Group A Streptococcal pharyngitis Among Pediatric Patients with Acute Pharyngitis in Gondar, Northwest Ethiopia |date = March 2023 |journal = Infection and Drug Resistance|volume = 16 |pages = 1637–1648 |doi = 10.2147/IDR.S402292 |doi-access = free |pmid = 36992964 |pmc = 0040342}}</ref>