View source for Biology:Streptococcus mitis

{{Short description|Species of bacterium}}
{{Speciesbox
| taxon = Streptococcus mitis
| authority = Andrewes and Horder 1906 (Approved Lists 1980)
| synonyms = ''Streptococcus mitior''<ref name="pmid7287885">{{cite journal |vauthors=Gross KC, Houghton MP, Roberts RB |title=Evaluation of blood culture media for isolation of pyridoxal-dependent ''Streptococcus mitior'' (''mitis'') |journal=J. Clin. Microbiol. |volume=14 |issue=3 |pages=266–72 |date=September 1981 |pmid=7287885 |pmc=271953 |doi=10.1128/jcm.14.3.266-272.1981}}</ref>
}}

'''''Streptococcus mitis''''' is a mesophilic alpha-hemolytic species of ''[[Biology:Streptococcus|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 [[Medicine:Infective endocarditis|infective endocarditis]].<ref name="Johnsborg" />

== 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.<ref name=":1" />

== 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.<ref>{{Cite journal |last1=Kutlu |first1=Selda Sayin |last2=Sacar |first2=Suzan |last3=Cevahir |first3=Nural |last4=Turgut |first4=Huseyin |date=2008-11-01 |title=Community-acquired ''Streptococcus mitis'' meningitis: a case report |journal=International Journal of Infectious Diseases |language=en |volume=12 |issue=6 |pages=e107–e109 |doi=10.1016/j.ijid.2008.01.003 |pmid=18378176 |issn=1201-9712|doi-access=free }}</ref> 

==Natural genetic transformation==

''S. mitis'' is competent for [[Biology:Transformation (genetics)|natural genetic transformation]].  Thus ''S. mitis'' cells are able to take up exogenous DNA and incorporate exogenous sequence information into their genome by [[Biology:Homologous recombination|homologous recombination]].<ref name=Johnsborg>{{cite journal |vauthors=Johnsborg O, Eldholm V, Bjørnstad ML, Håvarstein LS |title=A predatory mechanism dramatically increases the efficiency of lateral gene transfer in ''Streptococcus pneumoniae'' and related commensal species |journal=Mol. Microbiol. |volume=69 |issue=1 |pages=245–53 |year=2008 |pmid=18485065 |doi=10.1111/j.1365-2958.2008.06288.x |s2cid=30923996 |doi-access=free }}</ref> These bacteria can employ a predatory fratricidal mechanism for active acquisition of homologous DNA.<ref name=Johnsborg />

== 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. <ref name=":0">{{cite web |title=Surveyor 3 ''Streptococcus mitis'' (APSTREPMIT) |url=https://lsda.jsc.nasa.gov/scripts/experiment/exper.aspx?exp_index=1651 |access-date=27 December 2015 |publisher=NASA}}</ref>

=== 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.{{cn|date=February 2023}}

== Characteristics of ''Streptococcus mitis'' ==
{| class="wikitable sortable mw-collapsible"
|+The following table has Streptococcus mitis characteristics <ref name=":1">{{Cite web |last=Sapkota |first=Anupama |date=2021-01-06 |title=Streptococcus mitis- An Overview |url=https://microbenotes.com/streptococcus-mitis/ |access-date=2022-05-04 |website=Microbe Notes |language=en-US}}</ref>
!Test type
!Test
|'''Characteristics'''
|-
| rowspan="7" |Biochemical characters
|Gram stain
|Positive
|-
|Catalase
|Negative
|-
|Oxidase
|Positive
|-
|Methyl Red
|Positive
|-
|Voges Proskauer (VR)
|Negative
|-
|Coagulase
|Negative
|-
|DNase
|Negative
|-
| rowspan="2" |Morphological characters
|Shape
|Coccus
|-
|Arrangement
|Chains or pairs
|-
| rowspan="9" |Fermentation
|Glucose
|Positive
|-
|Fructose
|Positive
|-
|Galactose
|Positive
|-
|Lactose
|Positive
|-
|Maltose
|Negative
|-
|Mannitol
|Variable
|-
|Mannose
|Positive
|-
|Sucrose
|Positive
|-
|Starch
|Negative
|-
| rowspan="7" |Enzymatic Reactions
|Acetoin
|Negative
|-
|Acid Phosphatase
|Variable
|-
|Alkaline Phosphatase
|Positive
|-
|Hyaluronidase
|Negative
|-
|β-D-glucosidase
|Positive
|-
|Leucine aminopeptidase
|Positive
|-
|Neuraminidase
|Positive
|}

==References==
{{Reflist}}

==External links==
* [https://web.archive.org/web/20080921213543/http://rad.usuhs.edu/medpix/medpix_image.html?mode=image&pt_id=11626&imageid=40091&topic_id=5113&quiz=no#top S. mitis subdural empyema] from MedPix
* [http://bacdive.dsmz.de/index.php?search=14734&submit=Search Type strain of ''Streptococcus mitis'' at Bac''Dive'' -  the Bacterial Diversity Metadatabase]

{{Gram-positive firmicutes diseases}}

{{Taxonbar|from=Q684674}}

[[Category:Streptococcaceae]]
[[Category:Gram-positive bacteria]]



{{Sourceattribution|Streptococcus mitis}}