streptococcal infection

同

Streptococcus

関

specific causative agents and infections

WordNet

1. (medicine) the invasion of the body by pathogenic microorganisms and their multiplication which can lead to tissue damage and disease
2. (phonetics) the alteration of a speech sound under the influence of a neighboring sound
3. the pathological state resulting from the invasion of the body by pathogenic microorganisms
4. (international law) illegality that taints or contaminates a ship or cargo rendering it liable to seizure
5. moral corruption or contamination; "ambitious men are led astray by an infection that is almost unavoidable"
6. an incident in which an infectious disease is transmitted (同)contagion, transmission
7. of or relating to or caused by streptococci (同)streptococcic, strep

PrepTutorEJDIC

1. 〈U〉(病気の)伝染;感染 / 〈C〉伝染病
2. 連鎖球菌の(による)

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/01/19 17:21:22」(JST)

wiki en

[Wiki en表示]

Not to be confused with Staphylococcus.

Streptococcus
Scientific classification
Kingdom:	Bacteria
Phylum:	Firmicutes
Class:	Bacilli
Order:	Lactobacillales
Family:	Streptococcaceae
Genus:	Streptococcus Rosenbach, 1884
Species
S. agalactiae S. anginosus S. bovis S. canis S. constellatus S. dysgalactiae S. equinus S. iniae S. intermedius S. mitis S. mutans S. oralis S. parasanguinis S. peroris S. pneumoniae S. pseudopneumoniae S. pyogenes S. ratti S. salivarius S. tigurinus S. thermophilus S. sanguinis S. sobrinus S. suis S. uberis S. vestibularis S. viridans S. zooepidemicus

Streptococcus is a genus of spherical Gram-positive bacteria belonging to the phylum Firmicutes and the lactic acid bacteria group. Cellular division occurs along a single axis in these bacteria, and thus they grow in chains or pairs, hence the name—from Greek στρεπτός streptos, meaning easily bent or twisted, like a chain (twisted chain).

Contrast this with staphylococci, which divide along multiple axes and generate grape-like clusters of cells. Most streptococci are oxidase- and catalase-negative, and many are facultative anaerobes.

In 1984, many organisms formerly considered Streptococcus were separated out into the genera Enterococcus and Lactococcus. There are currently over 50 species recognised in this genus.

Pathogenesis and classification

Streptococcal classification.

In addition to streptococcal pharyngitis (strep throat), certain Streptococcus species are responsible for many cases of pink eye, meningitis, bacterial pneumonia, endocarditis, erysipelas and necrotizing fasciitis (the 'flesh-eating' bacterial infections). However, many streptococcal species are nonpathogenic, and form part of the commensal human microbiome of the mouth, skin, intestine, and upper respiratory tract. Furthermore, streptococci are a necessary ingredient in producing Emmentaler ("Swiss") cheese.

Species of Streptococcus are classified based on their hemolytic properties. Alpha hemolytic species cause oxidization of iron in hemoglobin molecules within red blood cells, giving it a greenish color on blood agar. Beta hemolytic species cause complete rupture of red blood cells. On blood agar, this appears as wide areas clear of blood cells surrounding bacterial colonies. Gamma-hemolytic species cause no hemolysis.

Beta-hemolytic streptococci are further characterised via Lancefield serotyping, which describes specific carbohydrates present on the bacterial cell wall. There are 20 described serotypes, named Lancefield groups A to V (excluding I and J).

In the medical setting, the most important groups are the alpha-hemolytic streptococci S. pneumoniae and Streptococcus Viridans-group, and the beta-hemolytic streptococci of Lancefield groups A and B (also known as “Group A strep” and “Group B strep”).

Alpha-hemolytic

Pneumococci

• S. pneumoniae (sometimes called Pneumococcus), is a leading cause of bacterial pneumonia and occasional etiology of otitis media, sinusitis, meningitis and peritonitis.

Inflammation is thought to be the major cause of how pneumococcus causes disease, hence the tendency of diagnoses associated with it to involve inflammation.

The Viridans group: alpha-hemolytic

• Streptococcus viridans is a pseudotaxonomic non-Linnean term for a large group of commensal streptococcal bacteria that are either α-hemolytic, producing a green coloration on blood agar plates (hence the name "viridans", from Latin "vĭrĭdis", green), or nonhemolytic. They possess no Lancefield antigens.

Beta-hemolytic

Alpha-hemolytic S. viridans (right) and beta-hemolytic S. pyogenes (left) streptococci growing on blood agar.

Group A

S. pyogenes, also known as Group A Streptococcus (GAS), is the causative agent in a wide range of Group A streptococcal infections. These infections may be non-invasive or invasive. The non-invasive infections tend to be more common and less severe. The most common of these infections include streptococcal pharyngitis (strep throat) and impetigo. Scarlet fever is also a non-invasive infection, but has not been as common in recent years.

The invasive infections caused by Group A β-hemolytic streptococcus tend to be more severe and less common. This occurs when the bacterium is able to infect areas where it is not usually found, such as the blood and the organs. The diseases that may be caused as a result of this include streptococcal toxic shock syndrome (STSS), necrotizing fasciitis (NF), pneumonia, and bacteremia.

Additional complications may be caused by GAS, namely acute rheumatic fever and acute glomerulonephritis. Rheumatic fever, a disease that affects the joints, kidneys, and heart valves, is a consequence of untreated strep A infection caused not by the bacterium itself. Rheumatic fever is caused by the antibodies created by the immune system to fight off the infection cross-reacting with other proteins in the body. This "cross-reaction" causes the body to essentially attack itself and leads to the damage above. Globally, GAS has been estimated to cause more than 500,000 deaths every year, making it one of the world's leading pathogens. Group A Streptococcus infection is generally diagnosed with a Rapid Strep Test or by culture.

Group B

S. agalactiae, or GBS, causes pneumonia and meningitis in neonates and the elderly, with occasional systemic bacteremia. They can also colonize the intestines and the female reproductive tract, increasing the risk for premature rupture of membranes during pregnancy, and transmission of the organism to the infant. The American College of Obstetricians and Gynecologists, American Academy of Pediatrics and the Centers for Disease Control recommend that all pregnant women between 35 and 37 weeks gestation should be tested for GBS. Women who test positive should be given prophylactic antibiotics during labor, which will usually prevent transmission to the infant.

In the UK, clinicians have been slow to implement the same standards as the US, Australia and Canada. In the UK, only 1% of maternity units test for the presence of Group B Streptococcus. Although the Royal College of Obstetricians and Gynaecologists issued risk-based guidelines in 2003 (due for review 2006), the implementation of these guidelines has been patchy. As a result, over 75 infants in the UK die each year of GBS-related disease, and another 600 or so suffer serious infection, most of which could be prevented; however, this is yet to be substantiated by randomized, controlled trial in the UK setting and, given the evidence for the efficacy of testing and treating from other countries, it may be that the large-scale trial necessary would receive neither funding nor ethics approval.

Group C

This group includes S. equi, which causes strangles in horses, and S. zooepidemicus—S. equi is a clonal descendent or biovar of the ancestral S. zooepidemicus—which causes infections in several species of mammals, including cattle and horses. Streptococcus dysgalactiae is also a member of Group C, β-haemolytic streptococci that can cause pharyngitis and other pyogenic infections similar to Group A streptococci.

Group D (enterococci)

Many former Group D streptococci have been reclassified and placed in the genus Enterococcus (including Enterococcus faecalis, Enterococcus faecium, Enterococcus durans, and Enterococcus avium). For example, Streptococcus faecalis is now Enterococcus faecalis.

The remaining nonenterococcal Group D strains include Streptococcus bovis and Streptococcus equinus.

Nonhemolytic streptococci rarely cause illness. However, weakly hemolytic group D beta-hemolytic streptococci and Listeria monocytogenes (which is actually a Gram-positive bacillus) should not be confused with nonhemolytic streptococci.

Group F streptococci

Group F streptococci were first described in 1934 by Long and Bliss amongst the "minute haemolytic streptococci". They are also known as Streptococcus anginosus (according to the Lancefield classification system) or as members of the S. milleri group (according to the European system).

Group G streptococci

These streptococci are usually, but not exclusively, beta-hemolytic. Streptococcus canis is an example of a GGS which is typically found on animals, but can cause infection in humans.

Group H streptococci

Group H streptococci is a very rare infection caused by the herptitis bacteria found in medium sized canines. Group H streptococci rarely causes illness unless a human has direct contact with the mouth of a canine. One of the most common ways this can be spread is human to canine, mouth-to-mouth contact. However, canine may lick the humans hand and infection can be spread as well.

Molecular taxonomy and phylogenetics

Phylogenetic tree of Streptococcus species, based on data from PATRIC. 16S groups are indicated by brackets and their key members are highlighted in red.

Streptococci have been divided into six groups on the basis of their 16S rDNA sequences: Anginosus, Bovis, Mitis, Mutans, Pyogenes and Salivarius. The 16S groups have been confirmed by whole genome sequencing (see figure). The important pathogens S. pneumoniae and S. pyogenes belong to the Mitis and Pyogenes groups, respectively, while the causing agent of dental caries,Streptococcus mutans, is basal to the Streptococcus group.

Genomics

The genomes of hundreds of species have been sequenced. Most Streptococcus genomes are 1.8 to 2.3 Mb in size and encode 1,700 to 2,300 proteins. Some important genomes are listed in the table. The four species shown in the table (pyogenes, agalactiae, pneumoniae, and mutans) have an average pairwise protein sequence identity of about 70%.

feature	S. pyogenes	S. agalactiae	S. pneumoniae	S. mutans
bp	1,852,442	2,211,488	2,160,837	2,030,921
ORFs	1792	2118	2236	1963
prophages	yes	no	no	no

Treatment

Main article: List of antibiotics

See also

• Quellung reaction
• Streptococcal infection in poultry
• Streptokinase

References

External links

• Streptococcus genomes and related information at PATRIC, a Bioinformatics Resource Center funded by NIAID
• "Adoption of perinatal group B streptococcal disease prevention recommendations by prenatal-care providers—Connecticut and Minnesota, 1998". MMWR Morb. Mortal. Wkly. Rep. 49 (11): 228–32. March 2000. PMID 10763673. 
• The Canadian Strep B Foundation
• The UK Group B Strep Support charity

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

• 1. 連鎖球菌扁桃咽頭炎の治療および予防 treatment and prevention of streptococcal tonsillopharyngitis
• 2. 成人におけるA群レンサ球菌（Streptococcus pyogenes）
  性菌血症 group a streptococcal streptococcus pyogenes bacteremia in adults
• 3. 小児におけるA群レンサ球菌（化膿連鎖球菌）性菌血症 group a streptococcal streptococcus pyogenes bacteremia in children
• 4. 妊娠していない成人におけるB群レンサ球菌感染症 group b streptococcal infections in nonpregnant adults
• 5. 小児および思春期における急性感染性咽頭炎の診断へのアプローチ approach to diagnosis of acute infectious pharyngitis in children and adolescents

English Journal

• Guttate Psoriasis Following Streptococcal Vulvovaginitis in a Five-year-old Girl.

• Hernandez M1, Simms-Cendan J2, Zendell K3.
• Journal of pediatric and adolescent gynecology.J Pediatr Adolesc Gynecol.2015 Oct;28(5):e127-9. doi: 10.1016/j.jpag.2014.10.007. Epub 2014 Oct 23.
• BACKGROUND: Guttate psoriasis is frequently associated with a preceding pharyngeal or perianal streptococcal infection in children. Despite Group A beta-hemolytic streptococci (GABHS) being the most common cause of specific bacterial vulvovaginitis in prepubertal girls, there are no reports of strep
• PMID 26024939

• Platelet-Dependent Neutrophil Function Is Dysregulated by M Protein from Streptococcus pyogenes.

• Hurley SM1, Kahn F1, Nordenfelt P1, Mörgelin M1, Sørensen OE1, Shannon O2.
• Infection and immunity.Infect Immun.2015 Sep;83(9):3515-25. doi: 10.1128/IAI.00508-15. Epub 2015 Jun 22.
• Platelets are rapidly responsive sentinel cells that patrol the bloodstream and contribute to the host response to infection. Platelets have been reported to form heterotypic aggregates with leukocytes and may modulate their function. Here, we have investigated platelet-neutrophil complex formation
• PMID 26099589

• A molecular trigger for intercontinental epidemics of group A Streptococcus.

• Zhu L, Olsen RJ, Nasser W, Beres SB, Vuopio J, Kristinsson KG, Gottfredsson M, Porter AR, DeLeo FR, Musser JM.
• The Journal of clinical investigation.J Clin Invest.2015 Sep 1;125(9):3545-59. doi: 10.1172/JCI82478. Epub 2015 Aug 10.
• The identification of the molecular events responsible for strain emergence, enhanced virulence, and epidemicity has been a long-pursued goal in infectious diseases research. A recent analysis of 3,615 genomes of serotype M1 group A Streptococcus strains (the so-called "flesh-eating" bacterium) iden
• PMID 26258415

Japanese Journal

• A群レンサ球菌感染関連関節炎の3例

• 佐藤 智,千代反田 雅子,堤 範音 [他]
• 日本小児科学会雑誌 = The journal of the Japan Pediatric Society 117(5), 877-881, 2013-05
• NAID 40019693769

• 臨床 小児の急性中耳炎とA群β溶血性連鎖球菌感染症

• 高橋 佳文
• 耳鼻咽喉科臨床 106(5), 397-402, 2013-05
• NAID 40019680927

• 抗大脳基底核抗体 (特集 Antibody Update)

• 林 雅晴
• Brain and nerve : 神経研究の進歩 65(4), 377-384, 2013-04
• NAID 40019677292

---

★リンクテーブル★

リンク元	「レンサ球菌感染」「レンサ球菌感染症」
拡張検索	「fulminant group A streptococcal infection」
関連記事	「infection」

「レンサ球菌感染」

　　[★]

英

streptococcal infection

関

レンサ球菌感染症、連鎖球菌感染症、連鎖球菌感染

「レンサ球菌感染症」

　　[★]

英

streptococcal infection

関

レンサ球菌感染、連鎖球菌感染症、連鎖球菌感染

「fulminant group A streptococcal infection」

　　[★] 劇症型A群溶血性連鎖球菌感染症

「infection」

　　[★]

• n.

• 感染、伝染、感染症

関

contagion、infect、infectious disease、infestation、transmission、transmit