Editing Mycobacterium tuberculosis (section)

== Microbiology ==
''M. tuberculosis'' [[obligate aerobe|requires oxygen to grow]], and is [[Motility|nonmotile]].<ref name="pmid10934532">{{cite journal | vauthors = Parish T, Stoker NG | title = Mycobacteria: bugs and bugbears (two steps forward and one step back) | journal = Molecular Biotechnology | volume = 13 | issue = 3 | pages = 191–200 | date = December 1999 | pmid = 10934532 | doi = 10.1385/MB:13:3:191 | s2cid = 28960959 | doi-access = free}}</ref><ref name=":1">{{Cite book |title=Mandell, Douglas, and Bennett's principles and practice of infectious diseases | veditors = Bennett JE, Dolin R, Blaser MJ | vauthors = Fitzgerald DW, Sterline TR, Haas DW |date=2015|publisher=Elsevier Saunders |isbn=978-1-4557-4801-3 |pages=2787 |chapter=251 – Mycobacterium tuberculosis|oclc=903327877}}</ref>  It divides every 18–24 hours. This is extremely slow compared with other bacteria, which tend to have division times measured in minutes (''[[Escherichia coli]]'' can divide roughly every 20 minutes). It is a small [[bacillus (shape)|bacillus]] that can withstand weak [[disinfectant]]s and can survive in a dry state for weeks. Its unusual [[Bacterial cell wall|cell wall]], rich in [[lipids]] such as [[mycolic acid]] and [[cord factor]] [[glycolipid]], is likely responsible for its resistance to [[Desiccation tolerance|desiccation]] and is a key [[virulence factor]].<ref>{{cite book|title=Medical Microbiology|vauthors=Murray PR, Rosenthal KS, Pfaller MA|publisher=Elsevier Mosby|year=2005}}</ref><ref name=":9">{{cite journal | vauthors = Hunter RL, Olsen MR, Jagannath C, Actor JK | title = Multiple roles of cord factor in the pathogenesis of primary, secondary, and cavitary tuberculosis, including a revised description of the pathology of secondary disease | journal = Annals of Clinical and Laboratory Science | volume = 36 | issue = 4 | pages = 371–386 | date = 2006 | pmid = 17127724 | url = https://pubmed.ncbi.nlm.nih.gov/17127724/ | access-date = 16 December 2022 | archive-date = 16 December 2022 | archive-url = https://web.archive.org/web/20221216103128/https://pubmed.ncbi.nlm.nih.gov/17127724/ | url-status = live}}</ref>

=== Microscopy ===
[[File:M.tuberculosis.jpg|thumb|Growth of ''Mycobacterium tuberculosis'' on Löwenstein-Jensen (A) and Ogawa medium (B), after six weeks at 37°C.]]
Other bacteria are commonly identified with a microscope by staining them with [[Gram staining|Gram stain]]. However, the mycolic acid in the cell wall of ''M. tuberculosis'' does not absorb the stain. Instead, acid-fast stains such as [[Ziehl–Neelsen stain]], or fluorescent stains such as [[Auramine O|auramine]] are used.<ref name=":0" /> Cells are curved rod-shaped and are often seen wrapped together, due to the presence of fatty acids in the cell wall that stick together.<ref>{{Cite web |url= http://textbookofbacteriology.net/tuberculosis.html |title= Mycobacterium tuberculosis and Tuberculosis |vauthors= Todar K |website= textbookofbacteriology.net |access-date= 2016-12-24 |archive-date= 24 December 2016 |archive-url= https://web.archive.org/web/20161224162909/http://textbookofbacteriology.net/tuberculosis.html |url-status= live}}</ref> This appearance is referred to as cording, like strands of cord that make up a rope.<ref name=":1" /> ''M. tuberculosis'' is characterized in tissue by caseating [[granulomas]] containing [[Langhans giant cell]]s, which have a "horseshoe" pattern of nuclei.{{citation needed|date=May 2024}}

=== Culture ===
[[File:Slant tubes of Löwenstein-Jensen medium with control, M tuberculosis, M avium and M gordonae.jpg|thumb|upright=0.6|Slant tubes of Löwenstein-Jensen medium. From left to right:{{unordered list|item_style=margin-bottom: 0|Negative control|''M. tuberculosis'': Dry-appearing colonies|''[[Mycobacterium avium complex]]'': Wet-appearing colonies|''[[M. gordonae]]'': Yellowish colonies}}]]
[[File:Mycobacteria Growth Indicator Tube (MGIT) samples in ultraviolet light.jpg|thumb|150px|[[Mycobacteria growth indicator tube]] samples emitting fluorescence in ultraviolet light]]
''M. tuberculosis'' can be grown in the laboratory. Compared to other commonly studied bacteria, ''M. tuberculosis'' has a remarkably slow growth rate, doubling roughly once per day. Commonly used [[Growth medium|media]] include liquids such as [[Middlebrook 7H9 Broth|Middlebrook 7H9]] or 7H12, egg-based solid media such as [[Löwenstein–Jensen medium|Lowenstein-Jensen]], and solid agar-based such as [[Middlebrook 7H11 Agar|Middlebrook 7H11]] or [[Middlebrook 7H10 Agar|7H10]].<ref name=":1" /><ref>{{Cite journal |last=Mousavi-Sagharchi |first=Seyyed Mohammad Amin |last2=Ghorbani |first2=Atousa |last3=Meskini |first3=Maryam |last4=Siadat |first4=Seyed Davar |date=2025-03-01 |title=Historical examination of tuberculosis; from ancient affliction to modern challenges |url=https://linkinghub.elsevier.com/retrieve/pii/S1876034124003836 |journal=Journal of Infection and Public Health |volume=18 |issue=3 |pages=102649 |doi=10.1016/j.jiph.2024.102649 |issn=1876-0341|doi-access=free }}</ref> Visible colonies require several weeks to grow on agar plates. [[Mycobacteria growth indicator tube]]s can contain a gel that emits fluorescent light if mycobacteria are grown. It is distinguished from other mycobacteria by its production of [[catalase]] and [[Niacin (substance)|niacin]].<ref>{{Cite book|chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK7812/|title=Medical Microbiology|vauthors=McMurray DN|date=1996|publisher=University of Texas Medical Branch at Galveston|isbn=978-0963117212|veditors=Baron S|edition=4th|location=Galveston (TX)|pmid=21413269|chapter=Mycobacteria and Nocardia|access-date=5 September 2017|archive-date=12 February 2009|archive-url=https://web.archive.org/web/20090212202626/http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.section.1833|url-status=live}}</ref> Other tests to confirm its identity include [[gene probe]]s and [[MALDI-TOF]].<ref>{{cite journal | vauthors = Bicmen C, Gunduz AT, Coskun M, Senol G, Cirak AK, Ozsoz A | title = Molecular detection and identification of mycobacterium tuberculosis complex and four clinically important nontuberculous mycobacterial species in smear-negative clinical samples by the genotype mycobacteria direct test | journal = Journal of Clinical Microbiology | volume = 49 | issue = 8 | pages = 2874–78 | date = August 2011 | pmid = 21653780 | pmc = 3147717 | doi = 10.1128/JCM.00612-11}}</ref><ref>{{cite journal | vauthors = Saleeb PG, Drake SK, Murray PR, Zelazny AM | title = Identification of mycobacteria in solid-culture media by matrix-assisted laser desorption ionization-time of flight mass spectrometry | journal = Journal of Clinical Microbiology | volume = 49 | issue = 5 | pages = 1790–94 | date = May 2011 | pmid = 21411597 | pmc = 3122647 | doi = 10.1128/JCM.02135-10}}</ref>

=== Morphology ===
Analysis of ''Mycobacterium tuberculosis'' via [[scanning electron microscope]] shows the bacteria are {{val|2.71|1.05|u=um}} in length with an average diameter of {{val|0.345|0.029|u=um}}.<ref name=":10" /> The [[Bacterial cell structure|outer membrane]] and plasma membrane surface areas were measured to be {{val|3.04|1.33|u=um2}} and {{val|2.67|1.19|u=um2}}, respectively. The cell, outer membrane, periplasm, plasma membrane, and cytoplasm volumes were {{val|0.293|0.113|u=fl}} (= μm<sup>3</sup>), {{val|0.006|0.003|u=fl}}, {{val|0.060|0.021|u=fl}}, {{val|0.019|0.008|u=fl}}, and {{val|0.210|0.091|u=fl}}, respectively. The average total [[Ribosome recycling factor|ribosome]] number was {{val|1672|568}} with ribosome density about {{val|716.5|171.4|up=0.1 fl}}.<ref name=":10" />
{| class="wikitable floatcenter"
|+''M. tb'' morphology summary<ref name=":10">{{cite journal | vauthors = Yamada H, Yamaguchi M, Chikamatsu K, Aono A, Mitarai S | title = Structome analysis of virulent Mycobacterium tuberculosis, which survives with only 700 ribosomes per 0.1 fl of cytoplasm | journal = PLOS ONE | volume = 10 | issue = 1 | pages = e0117109 | date = 2015-01-28 | pmid = 25629354 | pmc = 4309607 | doi = 10.1371/journal.pone.0117109 | bibcode = 2015PLoSO..1017109Y | doi-access = free}}</ref>
!Feature
!Magnitude
|-
|Length
|2.71 ± 1.05μm
|-
|Outer membrane surface area
|3.04 ± 1.33 μm<sup>2</sup>
|-
|Cell volume
|0.293 ± 0.113 fl (= μm<sup>3</sup>)
|}

=== Related Mycobacterium species ===
{{See also|Mycobacterium tuberculosis complex}}
''M. tuberculosis'' is part of a genetically related group of Mycobacterium species that has at least nine members:
* ''M. tuberculosis''<ref name="van Ingen2012">{{cite journal |vauthors=van Ingen J, Rahim Z, Mulder A, Boeree MJ, Simeone R, Brosch R, van Soolingen D |date=April 2012 |title=Characterization of Mycobacterium orygis as M. tuberculosis complex subspecies |journal=Emerging Infectious Diseases |volume=18 |issue=4 |pages=653–55 |doi=10.3201/eid1804.110888 |pmc=3309669 |pmid=22469053}}</ref> ''sensu stricto''
* ''[[Mycobacterium africanum|M. africanum]]''<ref name="van Ingen2012" />
* ''[[Mycobacterium canettii|M. canettii]]''<ref name="van Ingen2012" />
* ''[[Mycobacterium bovis|M. bovis]]''<ref name="van Ingen2012" />
* ''[[Mycobacterium caprae|M. caprae]]''<ref name="van Ingen2012" />
* ''[[Mycobacterium microti|M. microti]]''<ref name="van Ingen2012" />
* ''[[Mycobacterium pinnipedii|M. pinnipedii]]''<ref name="van Ingen2012" />
* ''[[Mycobacterium mungi|M. mungi]]''<ref name="van Ingen2012" />
* ''[[Mycobacterium orygis|M. orygis]]''<ref name="van Ingen2012" />