Mycobacterium
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2008-06-16T01:53:22Z
DumZiBoT
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robot Modifying: [[cs:Mycobacterium]]
{{Taxobox
| color = lightgrey
| name = ''Mycobacterium''
| image = Mycobacterium tuberculosis 01.jpg
| image_width = 240px
| image_caption = [[Transmission electron microscopy|TEM]] [[micrograph]] of ''M. tuberculosis''.
| regnum = [[Bacterium|Bacteria]]
| phylum = [[Actinobacteria]]
| ordo = [[Actinomycetales]]
| subordo = [[Corynebacterineae]]
| familia = '''Mycobacteriaceae'''
| genus = '''''Mycobacterium'''''
| genus_authority = Lehmann & Neumann 1896
| subdivision_ranks = [[Species]]
| subdivision =
See [[#Species|below]].
}}
'''''Mycobacterium''''' is a [[genus]] of [[Actinobacteria]], given its own family, the Mycobacteriaceae. The genus includes [[pathogen]]s known to cause serious diseases in mammals, including [[tuberculosis]] and [[leprosy]].<ref name=Sherris>{{cite book | author = Ryan KJ, Ray CG (editors) | title = Sherris Medical Microbiology | edition = 4th ed. | publisher = McGraw Hill | year = 2004 | isbn = 0-8385-8529-9 }}</ref> The [[Latin]] prefix ''"myco—"'' means both ''fungus'' and ''wax''; its use here relates to the "waxy" compounds in the cell wall.
{{TOCleft}}{{clear}}
== Microbiologic characteristics ==
[[Image:Mycobacterial cell wall diagram.png|thumb|300px|[[Mycobacterial]] [[cell wall]]: 1-outer lipids, 2-[[mycolic acid]], 3-[[polysaccharides]] ([[arabinogalactan]]), 4-[[peptidoglycan]], 5-[[plasma membrane]], 6-[[lipoarabinomannan]] (LAM), 7-[[phosphatidylinositol mannoside]], 8-cell wall skeleton]]
Mycobacteria are [[aerobic]] and nonmotile bacteria (except for the species ''[[Mycobacterium marinum]]'' which has been shown to be motile within [[macrophage]]s) that are characteristically [[Acid-fast|acid-alcohol fast]].<ref name=Sherris /> Mycobacteria do not contain [[endospores]] or [[capsules]], and are usually considered [[Gram-positive]]. While mycobacteria do not seem to fit the Gram-positive category from an [[empirical]] standpoint (i.e. they do not retain the crystal violet stain), they are classified as an acid-fast Gram-positive bacterium due to their lack of an outer [[cell membrane]]. All ''Mycobacterium'' species share a characteristic [[cell wall]], thicker than in many other bacteria, which is [[hydrophobic]], waxy, and rich in [[mycolic acids]]/mycolates. The cell wall makes a substantial contribution to the hardiness of this genus.
Many ''Mycobacterium'' species adapt readily to growth on very simple [[Substrate (biology)|substrates]], using [[ammonia]] or [[amino acid]]s as nitrogen sources and [[glycerol]] as a carbon source in the presence of mineral salts. Optimum growth temperatures vary widely according to the species and range from 25 °C to over 50 °C.
Some species can be very difficult to [[Microbiological culture|culture]] (i.e. they are ''fastidious''), sometimes taking over two years to develop in culture.{{Fact|date=August 2007}} Further, some species also have extremely long reproductive cycles — ''[[M. leprae]]'', may take more than 20 days to proceed through one division cycle (for comparison, some ''[[E. coli]]'' strains take only 20 minutes), making laboratory culture a slow process.<ref name=Sherris />
A natural division occurs between [[Slowly growing Mycobacteria|slowly]]– and [[Rapidly growing Mycobacteria|rapidly–growing]] species. Mycobacteria that form colonies clearly visible to the naked eye within 7 days on subculture are termed rapid growers, while those requiring longer periods are termed slow growers. Mycobacteria are slightly curved or straight rods between 0.2-0.6 µm wide by 1.0-10 µm long.
===Pigmentation===
Some mycobacteria produce [[carotenoid]] pigments without light. Others require photoactivation for pigment production.
*Photochromogens (Group I) produce nonpigmented colonies when grown in the dark and pigmented colonies only after exposure to light and reincubation.
**Ex: ''M. kansasii'', ''M. marinum'', ''M. simiae''.
*Scotochromogens (Group II) produce deep yellow to orange colonies when grown in either the light or dark.
**Ex: ''M. scrofulaceum'', ''M. gordonae'', ''M. xenopi'', ''M. szulgai''.
*Non-chromogens (Groups III & IV) are nonpigmented in the light and dark or have only a pale yellow, buff or tan pigment that does not intensify after light exposure.
**Ex: ''M. tuberculosis'', ''M. avium-intra-cellulare'', ''M. bovis'', ''M. ulcerans''
**Ex: ''M. fortuitum'', ''M. chelonae''
===Staining characteristics===
Mycobacteria are classical [[acid-fast]] organisms.<ref name=Baron>{{cite book | author = McMurray DN | editor = Baron S ''et al'' (eds.) | chapter = Mycobacteria and Nocardia | title = Baron's Medical Microbiology | edition = 4th ed. | publisher = Univ of Texas Medical Branch | year = 1996 | chapterurl = http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.section.1772| isbn = 0-9631172-1-1 }}</ref> Stains used in evaluation of tissue specimens or microbiological specimens include [[Fite's stain]], [[Ziehl-Neelsen stain]], and [[Kinyoun stain]].'''
Mycobacteria appear phenotypically most closely related to members of ''[[Nocardia]]'', ''[[Rhodococcus]]'' and ''[[Corynebacterium]]''.
== Ecological characteristics ==
Mycobacteria are widespread organisms, typical living in water (including [[tap water]] [[Water purification|treated]] with [[chlorine]]) and food sources. Some, however, including the tuberculosis and the leprosy organisms, appear to be [[obligate parasite]]s and are not found as free-living members of the genus.
== Pathogenicity ==
Mycobacteria can colonize their hosts without the hosts showing any adverse signs. For example, billions of people around the world are infected with ''[[M. tuberculosis]]'' but will never know it because they will not develop symptoms.
Mycobacterial infections are notoriously difficult to treat. The organisms are hardy due to their cell wall, which is neither truly [[gram-negative|Gram negative]] nor [[gram-positive|positive]], and unique to the family, they are naturally resistant to a number of [[antibiotics]] that work by destroying cell walls, such as [[penicillin]]. Also, because of this cell wall, they can survive long exposure to acids, alkalis, detergents, oxidative bursts, lysis by [[Complement system|complement]] and [[antibiotic]]s which naturally leads to [[antibiotic resistance]]. Most mycobacteria are susceptible to the antibiotics [[clarithromycin]] and [[rifamycin]], but antibiotic-resistant strains are known to exist.
===Medical classification===
Mycobacteria can be classified into several major groups for purpose of diagnosis and treatment: ''M. tuberculosis'' complex which can cause [[tuberculosis]]: ''M. tuberculosis, M. bovis, M. africanum, and M. microti''; ''M. leprae'' which causes [[Leprosy|Hansen's disease]] or leprosy; [[Nontuberculous mycobacteria]] '''(NTM)''' are all the other mycobacteria which can cause pulmonary disease resembling tuberculosis, lymphadenitis, skin disease, or disseminated disease.
==Phenotypic testing ==
Various phenotypic tests can be used to identify and distinguish different Mycobacteria species and strains.
[[Phenotypic testing of Mycobacteria]]
==Mycosides==
Mycosides are [[phenolic alcohols]] (such as [[phenolphthiocerol]]) that were shown to be components of mycobacterium [[glycolipids]] which are termed [[glycosides]] of phenolphthiocerol dimycocerosate (Smith DW et al., Nature 1960, 186, 887) There are 18 and 20 carbon atoms in mycosides A, and B, respectively.<ref>[http://www.cyberlipid.org/simple/simp0003.htm#10 fatty alcohols and aldehydes<!-- Bot generated title -->]</ref>
== Species ==
*''[[Mycobacterium abcessus|M. abscessus]]''
*''[[Mycobacterium africanum|M. africanum]]''
*''[[Mycobacterium agri|M. agri]]''
*''[[Mycobacterium aichiense|M. aichiense]]''
*''[[Mycobacterium alvei|M. alvei]]''
*''[[Mycobacterium arupense|M. arupense]]''
*''[[Mycobacterium asiaticum|M. asiaticum]]''
*''[[Mycobacterium aubagnense|M. aubagnense]]''
*''[[Mycobacterium aurum|M. aurum]]''
*''[[Mycobacterium austroafricanum|M. austroafricanum]]''
*''[[Mycobacterium avium complex|Mycobacterium avium complex (MAC)]],'' is a group of species which are a significant cause of death in [[AIDS]] patients. Species in this complex include:
*:''[[Mycobacterium avium avium|M. avium]]''
*:''[[Mycobacterium avium paratuberculosis|M. avium paratuberculosis]]'', which has been implicated in [[Crohn's disease]] in humans and [[Johne's disease]] in [[sheep]]
*:''[[Mycobacterium avium silvaticum|M. avium silvaticum]]''
*:''[[Mycobacterium avium hominissuis|M. avium "hominissuis"]]''
*:''[[Mycobacterium colombiense|M. colombiense]]''
*''[[Mycobacterium boenickei|M. boenickei]]''
*''[[Mycobacterium bohemicum|M. bohemicum]]''
*''[[Mycobacterium bolletii|M. bolletii]]''
*''[[Mycobacterium botniense|M. botniense]]''
*''[[Mycobacterium bovis|M. bovis]]''
*''[[Mycobacterium branderi|M. branderi]]''
*''[[Mycobacterium brisbanense|M. brisbanense]]''
*''[[Mycobacterium brumae|M. brumae]]''
*''[[Mycobacterium canariasense|M. canariasense]]''
*''[[Mycobacterium caprae|M. caprae]]''
*''[[Mycobacterium celatum|M. celatum]]''
*''[[Mycobacterium chelonae|M. chelonae]]'',
*''[[Mycobacterium chimaera|M. chimaera]]''
*''[[Mycobacterium chitae|M. chitae]]''
*''[[Mycobacterium chlorophenolicum|M. chlorophenolicum]]''
*''[[Mycobacterium chubuense|M. chubuense]]''
*''[[Mycobacterium conceptionense|M. conceptionense]]''
*''[[Mycobacterium confluentis|M. confluentis]]''
*''[[Mycobacterium conspicuum|M. conspicuum]]''
*''[[Mycobacterium cookii|M. cookii]]''
*''[[Mycobacterium cosmeticum|M. cosmeticum]]''
*''[[Mycobacterium diernhoferi|M. diernhoferi]]''
*''[[Mycobacterium doricum|M. doricum]]''
*''[[Mycobacterium duvalii|M. duvalii]]''
*''[[Mycobacterium elephantis|M. elephantis]]''
*''[[Mycobacterium fallax|M. fallax]]''
*''[[Mycobacterium farcinogenes|M. farcinogenes]]''
*''[[Mycobacterium flavescens|M. flavescens]]''
*''[[Mycobacterium florentinum|M. florentinum]]''
*''[[Mycobacterium fluoroanthenivorans|M. fluoroanthenivorans]]''
*''[[Mycobacterium fortuitum|M. fortuitum]]''
*''[[Mycobacterium fortuitum subsp. acetamidolyticum|M. fortuitum subsp. acetamidolyticum]]''
*''[[Mycobacterium frederiksbergense|M. frederiksbergense]]''
*''[[Mycobacterium gadium|M. gadium]]''
*''[[Mycobacterium gastri|M. gastri]]''
*''[[Mycobacterium genavense|M. genavense]]''
*''[[Mycobacterium gilvum|M. gilvum]]''
*''[[Mycobacterium goodii|M. goodii]]''
*''[[Mycobacterium gordonae|M. gordonae]]''
*''[[Mycobacterium haemophilum|M. haemophilum]]''
*''[[Mycobacterium hassiacum|M. hassiacum]]''
*''[[Mycobacterium heckeshornense|M. heckeshornense]]''
*''[[Mycobacterium heidelbergense|M. heidelbergense]]''
*''[[Mycobacterium hiberniae|M. hiberniae]]''
*''[[Mycobacterium hodleri|M. hodleri]]''
*''[[Mycobacterium holsaticum|M. holsaticum]]''
*''[[Mycobacterium houstonense|M. houstonense]]''
*''[[Mycobacterium immunogenum|M. immunogenum]]''
*''[[Mycobacterium interjectum|M. interjectum]]''
*''[[Mycobacterium intermedium|M. intermedium]]''
*''[[Mycobacterium intracellulare|M. intracellulare]]''
*''[[Mycobacterium kansasii|M. kansasii]]''
*''[[Mycobacterium komossense|M. komossense]]''
*''[[Mycobacterium kubicae|M. kubicae]]''
*''[[Mycobacterium kumamotonense|M. kumamotonense]]''
*''[[Mycobacterium lacus|M. lacus]]''
*''[[Mycobacterium lentiflavum|M. lentiflavum]]
*''[[Mycobacterium leprae|M. leprae]]'', which causes [[leprosy]]
*''[[Mycobacterium lepraemurium|M. lepraemurium]]''
*''[[Mycobacterium madagascariense|M. madagascariense]]''
*''[[Mycobacterium mageritense|M. mageritense]]''
*''[[Mycobacterium malmoense|M. malmoense]]''
*''[[Mycobacterium marinum|M. marinum]]''
*''[[Mycobacterium massiliense|M. massiliense]]''
*''[[Mycobacterium microti|M. microti]]''
*''[[Mycobacterium monacense|M. monacense]]''
*''[[Mycobacterium montefiorense|M. montefiorense]]''
*''[[Mycobacterium moriokaense|M. moriokaense]]''
*''[[Mycobacterium mucogenicum|M. mucogenicum]]''
*''[[Mycobacterium murale|M. murale]]''
*''[[Mycobacterium nebraskense|M. nebraskense]]''
*''[[Mycobacterium neoaurum|M. neoaurum]]''
*''[[Mycobacterium neworleansense|M. neworleansense]]''
*''[[Mycobacterium nonchromogenicum|M. nonchromogenicum]]''
*''[[Mycobacterium novocastrense|M. novocastrense]]''
*''[[Mycobacterium obuense|M. obuense]]''
*''[[Mycobacterium palustre|M. palustre]]''
*''[[Mycobacterium parafortuitum|M. parafortuitum]]''
*''[[Mycobacterium parascrofulaceum|M. parascrofulaceum]]''
*''[[Mycobacterium parmense|M. parmense]]''
*''[[Mycobacterium peregrinum|M. peregrinum]]''
*''[[Mycobacterium phlei|M. phlei]]''
*''[[Mycobacterium phocaicum|M. phocaicum]]''
*''[[Mycobacterium pinnipedii|M. pinnipedii]]''
*''[[Mycobacterium porcinum|M. porcinum]]''
*''[[Mycobacterium poriferae|M. poriferae]]''
*''[[Mycobacterium pseudoshottsii|M. pseudoshottsii]]''
*''[[Mycobacterium pulveris|M. pulveris]]''
*''[[Mycobacterium psychrotolerans|M. psychrotolerans]]''
*''[[Mycobacterium pyrenivorans|M. pyrenivorans]]''
*''[[Mycobacterium rhodesiae|M. rhodesiae]]''
*''[[Mycobacterium saskatchewanense|M. saskatchewanense]]''
*''[[Mycobacterium scrofulaceum|M. scrofulaceum]]''
*''[[Mycobacterium senegalense|M. senegalense]]''
*''[[Mycobacterium seoulense|M. seoulense]]''
*''[[Mycobacterium septicum|M. septicum]]''
*''[[Mycobacterium shimoidei|M. shimoidei]]''
*''[[Mycobacterium shottsii|M. shottsii]]''
*''[[Mycobacterium simiae|M. simiae]]''
*''[[Mycobacterium smegmatis|M. smegmatis]]''
*''[[Mycobacterium sphagni|M. sphagni]]''
*''[[Mycobacterium szulgai|M. szulgai]]''
*''[[Mycobacterium terrae|M. terrae]]''
*''[[Mycobacterium thermoresistibile|M. thermoresistibile]]''
*''[[Mycobacterium tokaiense|M. tokaiense]]''
*''[[Mycobacterium triplex|M. triplex]]''
*''[[Mycobacterium triviale|M. triviale]]''
*''[[Mycobacterium tuberculosis complex|Mycobacterium tuberculosis complex (MTBC)]],''members are causative agents of human and animal tuberculosis. Species in this complex include:
*:''[[Mycobacterium tuberculosis|M. tuberculosis]]'', the major cause of human [[tuberculosis]]
*:''[[Mycobacterium bovis|M. bovis]]''
*:''[[Mycobacterium bovis BCG|M. bovis BCG]]''
*:''[[Mycobacterium africanum|M. africanum]]''
*:''[[Mycobacterium canetti|M. canetti]]''
*:''[[Mycobacterium caprae|M. caprae]]''
*:''[[Mycobacterium pinnipedii|M. pinnipedii]]'''
*''[[Mycobacterium tusciae|M. tusciae]]''
*''[[Mycobacterium ulcerans|M. ulcerans]]'', which causes the [[Buruli ulcer|"Buruli", or "Bairnsdale, ulcer"]]
*''[[Mycobacterium vaccae|M. vaccae]]''
*''[[Mycobacterium vanbaalenii|M. vanbaalenii]]''
*''[[Mycobacterium wolinskyi|M. wolinskyi]]''
*''[[Mycobacterium xenopi|M. xenopi]]''
==Databases on Mycobacterium tuberculosis==
*Tuberculist- Genome Annotation database [http://genolist.pasteur.fr/TubercuList/]
*MTB Sysborg- Genome Annotation database from the Institute of Genomics and Integrative Biology [http://mtbsysborg.igib.res.in/]
*TB Structural Genomics Consortium- Structures of Mycobacterium tuberculosis proteins [http://www.doe-mbi.ucla.edu/TB/]
* MycDB - Mycobacterium database [http://kiev.physchem.kth.se/MycDB.html]
==References==
{{Reflist}}
===Further reading===
<div class="references-small">
* Diagnosis and Treatment of Disease Caused by Nontuberculous Mycobacteria. American Thoracic Society. Am J Respiratory and Critical Care Medicine. Aug 1997 156(2) Part 2 Supplement [http://www.thoracic.org/sections/publications/statements/resources/nontuberc1-27.pdf PDF format]
*RIDOM - Ribosomal Differentiation of Medical Microorganisms [http://www.ridom-rdna.de/]
*J.P. Euzéby: List of Prokaryotic Names with Standing in Nomenclature - Genus ''Mycobacterium'' [http://www.bacterio.cict.fr/m/mycobacterium.html]
</div>
[[Category:Acid fast bacilli]]
[[Category:Corynebacterineae]]
[[Category:Tuberculosis]]
[[Category:Bacteriology]]
[[Category:Bacterial diseases]]
[[Category:Microbiology]]
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[[cs:Mycobacterium]]
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[[es:Mycobacterium]]
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[[fr:Mycobacterium]]
[[ko:미코박테륨]]
[[id:Mikobakteria]]
[[it:Mycobacterium]]
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