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Streptococcus is a genus of gram-positive or spherical bacteria that belongs to the family Streptococcaceae, within the order Lactobacillales (lactic acid bacteria), in the phylum Bacillota. [2] Cell division in streptococci occurs along a single axis, thus when growing they tend to form pairs or chains, which may appear bent or twisted.
Reproduction of T. namibiensis occurs on a single plane; the cocci (a spherical bacterial cell) divide into a diplococcus or streptococcus arrangement. [ 13 ] [ 42 ] A diplococcus is a pair of cocci cells that can form chains, and streptococcus is a grape-like cluster of cells. [ 43 ]
According to some definitions, the term is used to describe Gram-negative bacteria. [3] [4] According to other definitions, the term also encompasses yeasts. [5] [6] The name spheroplast stems from the fact that after the microbe's cell wall is digested, membrane tension causes the cell to acquire a characteristic spherical shape. [4]
The encapsulated, Gram-positive, coccoid bacteria have a distinctive morphology on Gram stain, lancet-shaped diplococci. They have a polysaccharide capsule that acts as a virulence factor for the organism; more than 100 different serotypes are known, and these types differ in virulence, prevalence, and extent of drug resistance.
Chains of S. pyogenes bacteria (orange) at 900× magnification Gram stain of Streptococcus pyogenes. Unlike most bacterial pathogens, S. pyogenes only infects humans. Thus, zoonotic transmission from an animal (or animal products) to a human is rare. [8] S. pyogenes typically colonizes the throat, genital mucosa, rectum, and skin. Of healthy ...
Sucrose is the only sugar that bacteria can use to form this sticky polysaccharide. [1] However, other sugars—glucose, fructose, lactose—can also be digested by S. mutans, but they produce lactic acid as an end product. The combination of plaque and acid leads to dental decay. [12]
Streptococcus thermophilus formerly known as Streptococcus salivarius subsp. thermophilus [2] [1] is a gram-positive bacterium, and a fermentative facultative anaerobe, of the viridans group. [3] It tests negative for cytochrome , oxidase , and catalase , and positive for alpha-hemolytic activity. [ 3 ]
Bacteria are also used for the bioremediation of industrial toxic wastes. [231] In the chemical industry, bacteria are most important in the production of enantiomerically pure chemicals for use as pharmaceuticals or agrichemicals. [232] Bacteria can also be used in place of pesticides in biological pest control.