Biology:Streptococcus mitis
| Streptococcus mitis | |
|---|---|
Scientific classification 
| |
| Domain: | Bacteria |
| Phylum: | Bacillota |
| Class: | Bacilli |
| Order: | Lactobacillales |
| Family: | Streptococcaceae |
| Genus: | Streptococcus |
| Species: | S. mitis
|
| Binomial name | |
| Streptococcus mitis Andrewes and Horder 1906 (Approved Lists 1980)
| |
| Synonyms | |
|
Streptococcus mitior[1] | |
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 Streptococcus mitior. Streptococcus mitis is known to cause several medical conditions one of them being infective endocarditis.[2]
Classification
Members of the Streptococcus genera belong to lactic acid bacteria defined by the formation of lactic acid as an end-product of carbohydrate metabolism. The family Streptococcaceae is characterized by based upon its 16S rRNA gene sequence analysis within the low (< 50 mol%) G+C branch. There are over 50 species in the genus which are classified by their 16S rRNA sequences.[3]
Habitat
Streptococcus mitis primarily resides in the oral cavity which includes the mouth, nasopharynx, and throat. However, there have also been cases of it in the female genital tract, the gastrointestinal tract, and even in the integumentary system.[4]
Natural genetic transformation
S. mitis is competent for natural genetic transformation. Thus S. mitis cells are able to take up exogenous DNA and incorporate exogenous sequence information into their genome by homologous recombination.[2] These bacteria can employ a predatory fratricidal mechanism for active acquisition of homologous DNA.[2]
Moon Surveyor 3 probe
Approach
It has been reported that Streptococcus mitis identified and survived for over two years on the Surveyor 3 probe on the Moon. However, many NASA scientists speculate that this is most probably due to contamination upon return to Earth. The Apollo 12 crew received pieces of Surveyor in 1969, one of these was the TV camera. The probe was then analyzed to consider how the lunar environment affected the material. Surveyor 3 had not been sterilized before its launch because scientists wanted to see if organisms could survive the two and half years on the Moon, so looking for surviving organic material was a part of this analysis. [5]
Results
Upon inspection, a group found an amount of S. mitis inside a piece of foam located inside the camera. Culture plates were made and the identity was later confirmed as Streptococcus mitis at the US Communicable Disease Center at Atlanta, Georgia. At first, it was speculated that S. mitis had been picked up from the Moon but research later discovered that the residence of the bacteria on the probe had started after the probe returned.[citation needed]
Characteristics of Streptococcus mitis
| Test type | Test | Characteristics |
|---|---|---|
| Biochemical characters | Gram stain | Positive |
| Catalase | Negative | |
| Oxidase | Positive | |
| Methyl Red | Positive | |
| Voges Proskauer (VR) | Negative | |
| Coagulase | Negative | |
| DNase | Negative | |
| Morphological characters | Shape | Coccus |
| Arrangement | Chains or pairs | |
| Fermentation | Glucose | Positive |
| Fructose | Positive | |
| Galactose | Positive | |
| Lactose | Positive | |
| Maltose | Negative | |
| Mannitol | Variable | |
| Mannose | Positive | |
| Sucrose | Positive | |
| Starch | Negative | |
| Enzymatic Reactions | Acetoin | Negative |
| Acid Phosphatase | Variable | |
| Alkaline Phosphatase | Positive | |
| Hyaluronidase | Negative | |
| β-D-glucosidase | Positive | |
| Leucine aminopeptidase | Positive | |
| Neuraminidase | Positive |
References
- ↑ "Evaluation of blood culture media for isolation of pyridoxal-dependent Streptococcus mitior (mitis)". J. Clin. Microbiol. 14 (3): 266–72. September 1981. doi:10.1128/jcm.14.3.266-272.1981. PMID 7287885.
- ↑ 2.0 2.1 2.2 "A predatory mechanism dramatically increases the efficiency of lateral gene transfer in Streptococcus pneumoniae and related commensal species". Mol. Microbiol. 69 (1): 245–53. 2008. doi:10.1111/j.1365-2958.2008.06288.x. PMID 18485065.
- ↑ 3.0 3.1 Sapkota, Anupama (2021-01-06). "Streptococcus mitis- An Overview" (in en-US). https://microbenotes.com/streptococcus-mitis/.
- ↑ Kutlu, Selda Sayin; Sacar, Suzan; Cevahir, Nural; Turgut, Huseyin (2008-11-01). "Community-acquired Streptococcus mitis meningitis: a case report" (in en). International Journal of Infectious Diseases 12 (6): e107–e109. doi:10.1016/j.ijid.2008.01.003. ISSN 1201-9712. PMID 18378176.
- ↑ "Surveyor 3 Streptococcus mitis (APSTREPMIT)". NASA. https://lsda.jsc.nasa.gov/scripts/experiment/exper.aspx?exp_index=1651.
External links
- S. mitis subdural empyema from MedPix
- Type strain of Streptococcus mitis at BacDive - the Bacterial Diversity Metadatabase
Wikidata ☰ Q684674 entry
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