Treponema pallidum: Difference between revisions

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#REDIRECT [[Syphilis]]
{{Automatic taxobox
| image = Treponema pallidum.jpg
| image_width = 200px
| binomial = ''Treponema pallidum''
| binomial_authority = [[Fritz Schaudinn|Schaudinn]] & [[Erich Hoffmann|Hoffmann]], 1905
}}
'''''Treponema pallidum''''' is a  [[spirochaete]] [[bacterium]] with subspecies that cause [[treponema]]l diseases such as [[syphilis]], [[bejel]], [[pinta (disease)|pinta]], and [[yaws]]. The treponemes have a cytoplasmic and an outer membrane. Using [[light microscopy]], treponemes are only visible using [[dark field illumination]]. They are [[gram negative]], but some regard them too thin to be gram stained.
 
==Subspecies==
{{expand section|date=December 2010}}
At least four [[subspecies]] are known:
* ''Treponema pallidum pallidum'', which causes syphilis
* ''T. p. endemicum'', which causes bejel or endemic syphilis
* ''T. p. carateum'', which causes pinta
* ''T. p. pertenue'', which causes yaws
Some variation occurs as to which are considered subspecies, and which are species. The cause of pinta is sometimes described as ''Treponema carateum'', rather than a subspecies of ''T. pallidum'', even when the subspecies convention is used for the other agents.<ref name="pmid11825779">{{cite journal |author=Antal GM, Lukehart SA, Meheus AZ |title=The endemic treponematoses |journal=Microbes Infect. |volume=4 |issue=1 |pages=83–94 |date=January 2002 |pmid=11825779 |doi= 10.1016/S1286-4579(01)01513-1|url=http://linkinghub.elsevier.com/retrieve/pii/S1286457901015131}}</ref>
 
==Laboratory identification==
[[Image:Treponema pallidum - very high mag - extreme crop.jpg|thumb|right|150px|[[Micrograph]] showing ''T. pallidum'' (black and thin) - [[Dieterle stain]]]]
This bacterium can be detected with special stains, such as the [[Dieterle stain]].  ''T. pallidum'' is also detected by [[serology]], including [[nontreponemal]] [[Venereal Disease Research Laboratory test|VDRL]], [[rapid plasma reagin]], and treponemal antibody tests ([[FTA-ABS]]), ''T. pallidum'' immobilization reaction, and [[syphilis TPHA test]]).<ref name=Microbiology>{{cite book |author=Fisher, Bruce; Harvey, Richard P.; Champe, Pamela C. |title=Lippincott's Illustrated Reviews: Microbiology (Lippincott's Illustrated Reviews Series) |publisher=Lippincott Williams & Wilkins |location=Hagerstown, MD |year= |pages= |isbn=0-7817-8215-5 |oclc= |doi=}}</ref>
 
==Clinical significance==
{{unreferenced|section|date=July 2014}}
''T. p. pallidum'' is a motile spirochaete that is generally acquired by close [[sexually transmitted disease|sexual]] contact, entering the host via breaches in squamous or columnar epithelium. The organism can also be transmitted to a fetus by [[placenta|transplacental]] passage during the later stages of pregnancy, giving rise to congenital syphilis. The helical structure of ''T. p. pallidum'' allows it to move in a corkscrew motion through a viscous medium such as mucus. It gains access to the host's blood and lymph systems through tissue and mucous membranes.
 
The subspecies causing [[yaws]], [[Pinta (disease)|pinta]], and [[bejel]] are [[Comparative anatomy|morphologically]] and [[serology|serologically]] indistinguishable from ''T. p. pallidum'' (syphilis); however, their transmission is not venereal in nature and the course of each disease is significantly different.
 
==Genome==
In the 17 July 1998 issue of the journal ''[[Science (journal)|Science]]'', a group of biologists reported how they sequenced the [[genome]] of ''T. pallidum''.<ref name="pmid9665876">{{cite journal |author=Fraser CM, Norris SJ, Weinstock GM, ''et al.'' |title=Complete genome sequence of Treponema pallidum, the syphilis spirochete |journal=Science |volume=281 |issue=5375 |pages=375–88 |date=July 1998 |pmid=9665876 |doi= 10.1126/science.281.5375.375|url=http://www.sciencemag.org/cgi/pmidlookup?view=long&pmid=9665876}}</ref> The recent sequencing of the genomes of several spirochetes permits a thorough analysis of the similarities and differences within this bacterial phylum.  ''T. p. pallidum ''has one of the smallest bacterial genomes at 1.14 million base pairs, and has limited metabolic capabilities, reflecting its adaptation through genome reduction to the rich environment of mammalian tissue.
The shape of ''T. pallidum''  is flat and wavy, unlike the other spirochetes, which are helical.<ref>Clark, D.P., Dunlap, P.V, Madigan, J.T., Martinko, J.M. Brock Biology of Microorganism. San Francisco: Pearson. 2009. 79 p.</ref>
 
==Vaccine==
No [[vaccine]] for syphilis is available as of 2015. The outer membrane of ''T. pallidum'' has too few surface proteins for an [[antibody]] to be effective. Efforts to develop a safe and effective syphilis vaccine have been hindered by uncertainty about the relative importance of humoral and cellular mechanisms to protective immunity,{{Citation needed|date=December 2008}} and because ''T. pallidum'' outer membrane proteins have not been unambiguously identified.<ref name="pmid17890130">{{cite journal |author=Tomson FL, Conley PG, Norgard MV, Hagman KE |title=Assessment of cell-surface exposure and vaccinogenic potentials of Treponema pallidum candidate outer membrane proteins |journal=Microbes Infect. |volume=9 |issue=11 |pages=1267–75 |date=September 2007 |pmid=17890130 |pmc=2112743 |doi=10.1016/j.micinf.2007.05.018 |url=http://linkinghub.elsevier.com/retrieve/pii/S1286-4579(07)00200-6}}</ref>
 
==References==
{{Reflist|2}}
 
==Further reading==
* {{cite journal|last1=Althouse|first1=Benjamin M.|last2=Herbert-Dufresne|first2=Laurent|title=Epidemic cycles driven by host behaviour|journal=Journal of the Royal Society Interface|date=2014|pages=20140575|url=http://rsif.royalsocietypublishing.org/content/11/99/20140575.long|accessdate=November 6, 2014|volume = 11|doi = 10.1098/rsif.2014.0575}}
 
==External links==
*[http://www.cdc.gov/std/Syphilis/STDFact-Syphilis.htm "Syphilis- CDC Fact Sheet]." Centers for Disease Control and Prevention. May. 2004. Centers for Disease Control and Prevention. 7 February 2006
{{Gram-negative non-proteobacterial bacterial diseases}}
 
{{Use dmy dates|date=January 2011}}
 
{{DEFAULTSORT:Treponema Pallidum}}
[[Category:Treponema]]
[[Category:Syphilis]]
[[Category:Bacteria with sequenced genomes]]
[[Category:Bacteria described in 1905]]

Revision as of 18:58, 11 August 2015

Template:Automatic taxobox Treponema pallidum is a spirochaete bacterium with subspecies that cause treponemal diseases such as syphilis, bejel, pinta, and yaws. The treponemes have a cytoplasmic and an outer membrane. Using light microscopy, treponemes are only visible using dark field illumination. They are gram negative, but some regard them too thin to be gram stained.

Subspecies

At least four subspecies are known:

  • Treponema pallidum pallidum, which causes syphilis
  • T. p. endemicum, which causes bejel or endemic syphilis
  • T. p. carateum, which causes pinta
  • T. p. pertenue, which causes yaws

Some variation occurs as to which are considered subspecies, and which are species. The cause of pinta is sometimes described as Treponema carateum, rather than a subspecies of T. pallidum, even when the subspecies convention is used for the other agents.[1]

Laboratory identification

File:Treponema pallidum - very high mag - extreme crop.jpg
Micrograph showing T. pallidum (black and thin) - Dieterle stain

This bacterium can be detected with special stains, such as the Dieterle stain. T. pallidum is also detected by serology, including nontreponemal VDRL, rapid plasma reagin, and treponemal antibody tests (FTA-ABS), T. pallidum immobilization reaction, and syphilis TPHA test).[2]

Clinical significance

T. p. pallidum is a motile spirochaete that is generally acquired by close sexual contact, entering the host via breaches in squamous or columnar epithelium. The organism can also be transmitted to a fetus by transplacental passage during the later stages of pregnancy, giving rise to congenital syphilis. The helical structure of T. p. pallidum allows it to move in a corkscrew motion through a viscous medium such as mucus. It gains access to the host's blood and lymph systems through tissue and mucous membranes.

The subspecies causing yaws, pinta, and bejel are morphologically and serologically indistinguishable from T. p. pallidum (syphilis); however, their transmission is not venereal in nature and the course of each disease is significantly different.

Genome

In the 17 July 1998 issue of the journal Science, a group of biologists reported how they sequenced the genome of T. pallidum.[3] The recent sequencing of the genomes of several spirochetes permits a thorough analysis of the similarities and differences within this bacterial phylum. T. p. pallidum has one of the smallest bacterial genomes at 1.14 million base pairs, and has limited metabolic capabilities, reflecting its adaptation through genome reduction to the rich environment of mammalian tissue. The shape of T. pallidum is flat and wavy, unlike the other spirochetes, which are helical.[4]

Vaccine

No vaccine for syphilis is available as of 2015. The outer membrane of T. pallidum has too few surface proteins for an antibody to be effective. Efforts to develop a safe and effective syphilis vaccine have been hindered by uncertainty about the relative importance of humoral and cellular mechanisms to protective immunity,[citation needed] and because T. pallidum outer membrane proteins have not been unambiguously identified.[5]

References

  1. ↑ Antal GM, Lukehart SA, Meheus AZ (January 2002). "The endemic treponematoses". Microbes Infect. 4 (1): 83–94. doi:10.1016/S1286-4579(01)01513-1. PMID 11825779.
  2. ↑ Fisher, Bruce; Harvey, Richard P.; Champe, Pamela C. Lippincott's Illustrated Reviews: Microbiology (Lippincott's Illustrated Reviews Series). Hagerstown, MD: Lippincott Williams & Wilkins. ISBN 0-7817-8215-5.
  3. ↑ Fraser CM, Norris SJ, Weinstock GM; et al. (July 1998). "Complete genome sequence of Treponema pallidum, the syphilis spirochete". Science. 281 (5375): 375–88. doi:10.1126/science.281.5375.375. PMID 9665876.
  4. ↑ Clark, D.P., Dunlap, P.V, Madigan, J.T., Martinko, J.M. Brock Biology of Microorganism. San Francisco: Pearson. 2009. 79 p.
  5. ↑ Tomson FL, Conley PG, Norgard MV, Hagman KE (September 2007). "Assessment of cell-surface exposure and vaccinogenic potentials of Treponema pallidum candidate outer membrane proteins". Microbes Infect. 9 (11): 1267–75. doi:10.1016/j.micinf.2007.05.018. PMC 2112743. PMID 17890130.

Further reading

External links

  • "Syphilis- CDC Fact Sheet." Centers for Disease Control and Prevention. May. 2004. Centers for Disease Control and Prevention. 7 February 2006

Template:Gram-negative non-proteobacterial bacterial diseases

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