Mycobacterium avium complex: Difference between revisions

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'''''Mycobacterium avium ''complex''' is a group of [[mycobacteria]] comprising '''''Mycobacterium intracellulare''''' and '''''Mycobacterium avium''''' that are commonly grouped because they infect humans together; this group, in turn, is part of the group of [[nontuberculous mycobacteria]]. These bacteria cause [[Mycobacterium avium-intracellulare infection|''Mycobacterium avium-intracellulare'' infections]] or ''Mycobacterium avium'' complex infections in humans.<ref>{{cite web|title=Mycobacterium Avium Complex. MAI; MAC Information|url=https://patient.info/doctor/mycobacterium-avium-complex|publisher=Patient Info|date=29 August 2014}}</ref> These bacteria are common and are found in fresh and salt water, in household [[dust]] and in soil.<ref name=":0">{{Cite web|url=https://rarediseases.info.nih.gov/diseases/7123/mycobacterium-avium-complex-infections|archive-url=https://web.archive.org/web/20200208175000/https://rarediseases.info.nih.gov/diseases/7123/mycobacterium-avium-complex-infections|url-status=dead|archive-date=February 8, 2020|title=Mycobacterium Avium Complex infections {{!}} Genetic and Rare Diseases Information Center (GARD) – an NCATS Program|website=rarediseases.info.nih.gov|language=en|access-date=2020-03-29}}</ref> MAC bacteria usually cause infection in those who are [[immunocompromised]] or those with severe [[lung disease]].

==Description==

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'''Physiology'''

* Growth on [[Löwenstein-Jensen]] medium and [[Middlebrook 7H10 Agar|Middlebrook 7H10 agar]] occurs at 37{{nbsp}}°C after seven or more days.

* The complex can be (but is not often) resistant to [[isoniazid]], [[ethambutol]], [[rifampin]], and [[streptomycin]].<ref name="pmid29054853">{{cite journal | vauthors = Haworth CS, Banks J, Capstick T, Fisher AJ, Gorsuch T, Laurenson IF, Leitch A, Loebinger MR, Milburn HJ, Nightingale M, Ormerod P, Shingadia D, Smith D, Whitehead N, Wilson R, Floto RA | title = British Thoracic Society guidelines for the management of non-tuberculous mycobacterial pulmonary disease (NTM-PD) | journal = Thorax | volume = 72 | issue = Suppl 2 | pages = ii1–ii64 | date = November 2017 | pmid = 29054853 | doi = 10.1136/thoraxjnl-2017-210927 | doi-access = free }}</ref>

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==Human health==

MAC bacteria enter most people's body when inhaled into the lungs or swallowed, but only cause infection in those who are [[immunocompromised]] or who have severe [[lung disease]] such as those with [[cystic fibrosis]] or [[chronic obstructive lung disease]] (COPD).<ref name=":0" /> [[Mycobacterium avium-intracellulare infection|MAC infection]] can cause COPD and [[lymphadenitis]], and can cause disseminated disease, especially in people with [[immunodeficiency]].<ref name=Tropical/>{{rp|245}}

During the last decade ''Mycobacterium chimaera'' (see below) infections following cardiothoracic surgery, especially open-heart surgery, have been increasingly reported worldwide.<ref>{{Cite journal |lastlast1=Riccardi |firstfirst1=Niccolò |last2=Monticelli |first2=Jacopo |last3=Antonello |first3=Roberta Maria |last4=Luzzati |first4=Roberto |last5=Gabrielli |first5=Marco |last6=Ferrarese |first6=Maurizio |last7=Codecasa |first7=Luigi |last8=Di Bella |first8=Stefano |last9=Giacobbe |first9=Daniele Roberto |date=2020 |title=Mycobacterium chimaera infections: An update |url=https://linkinghub.elsevier.com/retrieve/pii/S1341321X19303459 |journal=Journal of Infection and Chemotherapy |language=en |volume=26 |issue=3 |pages=199–205 |doi=10.1016/j.jiac.2019.11.004|pmid=31843377 |url-access=subscription }}</ref> Infections usually involve the respiratory system. ''Mycobacterium chimaera'' is acquired during cardiopulmonary bypass via bioaerosols emitted from contaminated heater-cooler units water systems. Due to nonspecific symptoms and long latency, postoperative ''Mycobacterium chimaera'' infections may not be promptly diagnosed and treated, and may become life-threatening.

==History==

In 2004, Tortoli et al. proposed the name ''M. chimaera'' for strains that a reverse hybridization–based line probe assay suggested belonged to MAIS (''M. avium–M. intracellulare–M. scrofulaceum'' group), but were different from ''M. avium'', ''M. intracellulare'', or ''M. scrofulaceum''. The new species name comes from the [[chimera (mythology)|Chimera]], a mythological being made up of parts of three different animals.<ref>{{cite journal |last=Henry |first=Ronnie |date=March 2017 |title=Etymologia: Mycobacterium chimaera |journal= Emerg Infect Dis |volume=23 |issue=3 |pages=499 |doi=10.3201/eid2303.ET2303 |quote=Citing public ___domain text from the CDC.|pmc=5382748 }}</ref><ref>{{cite journal|last1=Tortoli|first1=E|last2=Rindi|first2=L|last3=Garcia|first3=MJ|last4=Chiaradonna|first4=P|last5=Dei|first5=R|last6=Garzelli|first6=C|last7=Kroppenstedt|first7=RM|last8=Lari|first8=N|last9=Mattei|first9=R|last10=Mariottini|first10=A|last11=Mazzarelli|first11=G|last12=Murcia|first12=MI|last13=Nanetti|first13=A|last14=Piccoli|first14=P|last15=Scarparo|first15=C|title=Proposal to elevate the genetic variant MAC-A, included in the Mycobacterium avium complex, to species rank as Mycobacterium chimaera sp. nov.|journal=International Journal of Systematic and Evolutionary Microbiology|date=July 2004|volume=54|issue=Pt 4|pages=1277–85|pmid=15280303|doi=10.1099/ijs.0.02777-0}}</ref>

==In popular culture==

Twitch's #1 female streamer [[Ironmouse]] described in 2021 that she suffered from MAC as a result of her [[common variable immunodeficiency]].

==References==

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[[Category:Nontuberculous mycobacteria|avium complex]]

[[Category:Bacteria described in 1965]]

[[Category:Pathogenic bacteria]]