Streptococcus salivarius

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1. Classification

a. Higher order taxa

Domain: Bacteria
Phylum: Firmicutes
Class: Bacilli
Order: Lactobacillales
Family: Streptococcaceae
Genus: Streptococcus
Species: Streptococcus salivarius

2. Description and significance

S. salivarius is a spherical, Gram-positive, facultative anaerobic commensal bacterium that is both catalase and oxidase negative. As one of the first colonizers of the human oral cavity, upper respiratory tract, and gut after birth, S. salivarius is thought to contribute to immune homeostasis and regulate inflammatory response. Thus, the bacterium is most often harmless but considered an opportunistic pathogen (1).

Humans are introduced to S. salivarius within a few hours after birth, inhabiting the mouth and upper respiratory tract, making it one of the first commensal bacteria humans are exposed to (2). Early exposure allows humans to acquire immunity, so S. salivarius is usually considered harmless. However, while immunity is established during infancy, the bacteria are opportunistic pathogens, proving to be detrimental under certain circumstances, such as entrance to the bloodstream (3). Due to its opportunistic nature, S. salivarius has been linked to cases of sepsis in immunocompromised patients with neutropenia, a disease associated with a depleted level of white blood cells in the body (3).

3. Genome structure

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4. Cell structure

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5. Metabolic processes

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6. Ecology

Habitat; symbiosis; contributions to the environment.

7. Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

7. Key microorganisms

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8. Current Research

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9. References

It is required that you add at least five primary research articles (in same format as the sample reference below) that corresponds to the info that you added to this page. [Sample reference] Faller, A., and Schleifer, K. "Modified Oxidase and Benzidine Tests for Separation of Staphylococci from Micrococci". Journal of Clinical Microbiology. 1981. Volume 13. p. 1031-1035.