Editing Anaerobic organism (section)

==Classifications==
[[Image:Ana.png|300px|thumb|right|Aerobic and anaerobic [[bacteria]] can be differentiated by culturing them in test tubes of [[thioglycollate broth]]: {{ordered list| [[Obligate aerobe]]s need oxygen because they cannot ferment or respire anaerobically. They gather at the top of the tube where the oxygen concentration is highest. | [[Obligate anaerobe]]s are poisoned by oxygen, so they gather at the bottom of the tube where the oxygen concentration is lowest. | [[Facultative anaerobes]] can grow with or without oxygen because they can metabolize energy aerobically or anaerobically. They gather mostly at the top because aerobic respiration generates more [[adenosine triphosphate]] (ATP) than either fermentation or anaerobic respiration. | [[Microaerophile]]s need oxygen because they cannot ferment or respire anaerobically. However, they are poisoned by high concentrations of oxygen. They gather in the upper part of the test tube but not the very top. | Aerotolerant organisms do not require oxygen as they metabolize energy anaerobically. Unlike obligate anaerobes, however, they are not poisoned by [[oxygen]]. They can/will be evenly distributed throughout the test tube.}} ]]

For practical purposes, there are three categories of anaerobe:
* '''[[Obligate anaerobe]]s''', which are harmed by the presence of oxygen.<ref name="Prescott-1996">{{cite book |vauthors=Prescott LM, Harley JP, Klein DA |title=Microbiology |publisher = Wm. C. Brown Publishers |year=1996 |edition=3rd |pages=130–131| isbn = 978-0-697-29390-9}}</ref><ref name="Brooks-2007">{{cite book |vauthors=Brooks GF, Carroll KC, Butel JS, Morse SA |title=Jawetz, Melnick & Adelberg's Medical Microbiology |publisher = McGraw Hill |year=2007 |edition=24th |pages=307–312| isbn = 978-0-07-128735-7 }}</ref> Two examples of obligate anaerobes are ''Clostridium botulinum'' and the bacteria which live near hydrothermal vents on the deep-sea ocean floor.
* '''[[Aerotolerant|Aerotolerant organism]]s''', which cannot use oxygen for growth, but tolerate its presence.<ref name="Hogg-2005">{{cite book |author=Hogg, S. |title=Essential Microbiology| publisher = Wiley |year=2005 |edition=1st |pages=99–100| isbn = 978-0-471-49754-7}}</ref>
* '''[[Facultative anaerobic organism|Facultative anaerobe]]s''', which can grow without oxygen but use oxygen if it is present.<ref name="Hogg-2005"/>

However, this classification has been questioned after recent research showed that human "obligate anaerobes" (such as ''Finegoldia magna'' or the methanogenic archaea ''[[Methanobrevibacter smithii]]'') can be grown in aerobic atmosphere if the culture medium is supplemented with antioxidants such as [[ascorbic acid]], [[glutathione]] and [[uric acid]].<ref>{{Cite journal|last1=La Scola|first1=B.|last2=Khelaifia|first2=S.|last3=Lagier|first3=J.-C.|last4=Raoult|first4=D.|date=2014|title=Aerobic culture of anaerobic bacteria using antioxidants: a preliminary report|journal=European Journal of Clinical Microbiology & Infectious Diseases|volume=33|issue=10|pages=1781–1783|doi=10.1007/s10096-014-2137-4|pmid=24820294|s2cid=16682688|issn=0934-9723}}</ref><ref>{{Cite journal|last1=Dione|first1=N.|last2=Khelaifia|first2=S.|last3=La Scola|first3=B.|last4=Lagier|first4=J.C.|last5=Raoult|first5=D.|date=2016|title=A quasi-universal medium to break the aerobic/anaerobic bacterial culture dichotomy in clinical microbiology|journal=Clinical Microbiology and Infection|volume=22|issue=1|pages=53–58|doi=10.1016/j.cmi.2015.10.032|pmid=26577141|doi-access=free}}</ref><ref>{{Cite journal|last1=Khelaifia|first1=S.|last2=Lagier|first2=J.-C.|last3=Nkamga|first3=V. D.|last4=Guilhot|first4=E.|last5=Drancourt|first5=M.|last6=Raoult|first6=D.|date=2016|title=Aerobic culture of methanogenic archaea without an external source of hydrogen|journal=European Journal of Clinical Microbiology & Infectious Diseases|volume=35|issue=6|pages=985–991|doi=10.1007/s10096-016-2627-7|pmid=27010812|s2cid=17258102|issn=0934-9723}}</ref><ref>{{Cite journal|last1=Traore|first1=S.I.|last2=Khelaifia|first2=S.|last3=Armstrong|first3=N.|last4=Lagier|first4=J.C.|last5=Raoult|first5=D.|date=2019|title=Isolation and culture of Methanobrevibacter smithii by co-culture with hydrogen-producing bacteria on agar plates|journal=Clinical Microbiology and Infection|volume=25|issue=12|pages=1561.e1–1561.e5|doi=10.1016/j.cmi.2019.04.008|pmid=30986553|doi-access=free}}</ref>