| Streptococcus downei | |
|---|---|
Scientific classification  | |
| Domain: | Bacteria |
| Phylum: | Bacillota |
| Class: | Bacilli |
| Order: | Lactobacillales |
| Family: | Streptococcaceae |
| Genus: | Streptococcus |
| Species: | S. downei |
| Binomial name | |
| Streptococcus downei Whiley et al. 1988 | |
Streptococcus downei is a Gram-positive bacterium, with type strain MFe28 (NCTC 11391T). [1] It is thought to be cariogenic.
Streptococcus is a genus of gram-positive coccus or spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales, in the phylum Bacillota. Cell division in streptococci occurs along a single axis, so as they grow, they tend to form pairs or chains that may appear bent or twisted. This differs from staphylococci, which divide along multiple axes, thereby generating irregular, grape-like clusters of cells. Most streptococci are oxidase-negative and catalase-negative, and many are facultative anaerobes.
Escherichia coli, also known as E. coli, is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus Escherichia that is commonly found in the lower intestine of warm-blooded organisms. Most E. coli strains are harmless, but some serotypes (EPEC, ETEC etc.) can cause serious food poisoning in their hosts, and are occasionally responsible for food contamination incidents that prompt product recalls. Most strains do not cause disease in humans and are part of the normal microbiota of the gut; such strains are harmless or even beneficial to humans (although these strains tend to be less studied than the pathogenic ones). For example, some strains of E. coli benefit their hosts by producing vitamin K2 or by preventing the colonization of the intestine by pathogenic bacteria. These mutually beneficial relationships between E. coli and humans are a type of mutualistic biological relationship — where both the humans and the E. coli are benefitting each other. E. coli is expelled into the environment within fecal matter. The bacterium grows massively in fresh faecal matter under aerobic conditions for three days, but its numbers decline slowly afterwards.
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 that tend to link in chains. They are clinically important for humans, as they are an infrequent, but usually pathogenic, part of the skin microbiota that can cause Group A streptococcal infection. S. pyogenes is the predominant species harboring the 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 mm) zones of beta-hemolysis, a complete destruction of red blood cells. The name group A (beta-hemolytic) Streptococcus (GABHS) is thus also used.
Frederick Griffith (1877–1941) was a British bacteriologist whose focus was the epidemiology and pathology of bacterial pneumonia. In January 1928 he reported what is now known as Griffith's Experiment, the first widely accepted demonstrations of bacterial transformation, whereby a bacterium distinctly changes its form and function.
Optochin is a derivative of quinine introduced in 1911 by Morgenroth and Levy with the intention to treat pneumococci infection. In very high dilutions, it inhibits the growth of representatives of all four groups of pneumococci in vitro. That is the main reason it is now used in bacteriology for the differentiation of Streptococcus pneumoniae, which is optochin-sensitive, from the other, resistant alpha-hemolytic streptococci, sometimes called the viridans streptococci because of the green colouration on blood agar around colonies.
The bacteria capsule is a large structure common to many bacteria. It is a polysaccharide layer that lies outside the cell envelope, and is thus deemed part of the outer envelope of a bacterial cell. It is a well-organized layer, not easily washed off, and it can be the cause of various diseases.
Streptococcus thermophilus formerly known as Streptococcus salivarius subsp. thermophilus is a gram-positive bacterium, and a fermentative facultative anaerobe, of the viridans group. It tests negative for cytochrome, oxidase, and catalase, and positive for alpha-hemolytic activity. It is non-motile and does not form endospores. S. thermophilus is fimbriated.
Enterobacter cloacae is a clinically significant Gram-negative, facultatively-anaerobic, rod-shaped bacterium.
Streptococcus equinus is a Gram-positive, nonhemolytic, nonpathogenic, lactic acid bacterium of the genus Streptococcus. It is the principal Streptococcus found in the alimentary canal of a horse, and makes up the majority of the bacterial flora in horse feces. Equivalence with Streptococcus bovis has been contested.
Streptococcus iniae is a species of Gram-positive, sphere-shaped bacterium belonging to the genus Streptococcus. Since its isolation from an Amazon freshwater dolphin in the 1970s, S. iniae has emerged as a leading fish pathogen in aquaculture operations worldwide, resulting in over US$100M in annual losses. Since its discovery, S. iniae infections have been reported in at least 27 species of cultured or wild fish from around the world. Freshwater and saltwater fish including tilapia, red drum, hybrid striped bass, and rainbow trout are among those susceptible to infection by S. iniae. Infections in fish manifest as meningoencephalitis, skin lesions, and septicemia.
Bacteriophage T12 is a bacteriophage that infects Streptococcus pyogenes bacteria. It is a proposed species of the family Siphoviridae in the order Caudovirales also known as tailed viruses. It converts a harmless strain of bacteria into a virulent strain. It carries the speA gene which codes for erythrogenic toxin A. speA is also known as streptococcal pyogenic exotoxin A, scarlet fever toxin A, or even scarlatinal toxin. Note that the name of the gene "speA" is italicized; the name of the toxin "speA" is not italicized. Erythrogenic toxin A converts a harmless, non-virulent strain of Streptococcus pyogenes to a virulent strain through lysogeny, a life cycle which is characterized by the ability of the genome to become a part of the host cell and be stably maintained there for generations. Phages with a lysogenic life cycle are also called temperate phages. Bacteriophage T12, proposed member of family Siphoviridae including related speA-carrying bacteriophages, is also a prototypic phage for all the speA-carrying phages of Streptococcus pyogenes, meaning that its genome is the prototype for the genomes of all such phages of S. pyogenes. It is the main suspect as the cause of scarlet fever, an infectious disease that affects small children.
Enterococcus hirae is a species of Enterococcus. Its type strain is NCDO 1258. It is involved in growth depression in young chickens and endocarditis and sepsis in humans.
Desulfitobacterium hafniense is a species of gram positive bacteria, its type strain is DCB-2T..
Bacillus vallismortis is a species of bacteria, with type strain DV1-F-3.
Streptococcus infantarius is a species of bacteria.
Lentibacillus salicampi is a moderately halophilic bacterium, the type species of its genus. It is Gram-variable, aerobic, endospore-forming and rod-shaped, with type strain SF-20(T).
Streptococcus cristatus is a species of viridans Streptococcus with tufted fibrils, first isolated from the human oral cavity and throat. The type strain is strain CR311.
Streptococcus orisratti is a species of oral Streptococcus bacteria first isolated from Sprague–Dawley rats, hence its name. Its type strain is A63T.
Granada medium is a selective and differential culture medium designed to selectively isolate Streptococcus agalactiae and differentiate it from other microorganisms. Granada Medium was developed by Dr. Manuel Rosa-Fraile et al. at the Service of Microbiology in the Hospital Virgen de las Nieves in Granada (Spain).
Robert George Everitt Murray was an English-Canadian bacteriologist. He is known for his research on bacterial structure and pathology, as well as bacterial taxonomy.
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