''Streptococcus oralis'' is a

Gram positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bact ...

bacterium that grows characteristically in chains. It forms small white

colonies In modern parlance, a colony is a territory subject to a form of foreign rule. Though dominated by the foreign colonizers, colonies remain separate from the administration of the original country of the colonizers, the '' metropolitan state'' ...

on a Wilkins-Chalgren

agar Agar ( or ), or agar-agar, is a jelly-like substance consisting of polysaccharides obtained from the cell walls of some species of red algae, primarily from ogonori (''Gracilaria'') and "tengusa" (''Gelidiaceae''). As found in nature, agar is ...

plate. It is found in high numbers in the oral cavity. It has been classified as a member of the ''

Streptococcus mitis ''Streptococcus mitis'' is a mesophilic alpha-hemolytic species of ''Streptococcus'' that inhabits the oral cavity. It is coccus (spherical shaped), gram-positive, catalase negative, and facultative anaerobe. It was previously classified as ''Str ...

'' group. Members of this group are

opportunistic pathogen An opportunistic infection is an infection caused by pathogens (bacteria, fungi, parasites or viruses) that take advantage of an opportunity not normally available. These opportunities can stem from a variety of sources, such as a weakened immune ...

s. Strains of ''S. oralis'' produce

neuraminidase Exo-α-sialidase (EC 3.2.1.18, sialidase, neuraminidase; systematic name acetylneuraminyl hydrolase) is a glycoside hydrolase that cleaves the glycosidic linkages of neuraminic acids: : Hydrolysis of α-(2→3)-, α-(2→6)-, α-(2→8)- glycos ...

and an IgA

protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the ...

and cannot bind

α-amylase α-Amylase is an enzyme (EC 3.2.1.1; systematic name 4-α-D-glucan glucanohydrolase) that hydrolyses α bonds of large, α-linked polysaccharides, such as starch and glycogen, yielding shorter chains thereof, dextrins, and maltose: :Endohyd ...

Natural genetic transformation

''S. oralis'' is competent for natural genetic transformation. Thus ''S. oralis'' cells are able to take up exogenous DNA and incorporate exogenous sequence information into their genomes by

homologous recombination Homologous recombination is a type of genetic recombination in which genetic information is exchanged between two similar or identical molecules of double-stranded or single-stranded nucleic acids (usually DNA as in cellular organisms but may ...

. These bacteria can employ a predatory fratricidal mechanism for active acquisition of homologous DNA.

References

Note

External links

Type strain of ''Streptococcus oralis'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
Gram-positive bacteria Streptococcaceae Bacteria described in 1982 {{lactobacilli-stub