Mycobacterium avium complex: Difference between revisions

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{{Short description|Group of bacteria}}

{{Distinguish|Mycobacterium tuberculosis complex}}{{italic title|string=Mycobacterium avium}}

{{Taxobox

| name = ''Mycobacterium avium'' complex

| ___domain = [[Bacteria]]

| phylum = [[ActinobacteriaActinomycetota]]

| ordoclassis = [[ActinomycetalesActinomycetia]]

| subordoordo = [[CorynebacterineaeMycobacteriales]]

| familia = [[Mycobacteriaceae]]

| genus = ''[[Mycobacterium]]''

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| binomial2 = ''Mycobacterium avium''

| binomial2_authority = Chester 1901 emend. Thorel et al. 1990

}}

'''''Mycobacterium avium ''complex''' is a group of [[mycobacteria]] comprising '''''Mycobacterium intracellulare''''' and '''''Mycobacterium avium''''' (No mention of ''M. chimera'' in ref) that are commonly grouped together because they infect humans together; this group, in turn, is part of the group of [[nontuberculous mycobacteria]]. These bacteria cause disease in humans called [[Mycobacterium avium-intracellulare infection|''Mycobacterium avium-intracellulare'' infectioninfections]] or ''Mycobacterium avium'' complex infectioninfections 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==

[[File:Slant tubes of Löwenstein-Jensen medium with control, M tuberculosis, M avium and M gordonae.jpg|thumb|150px|Slant tubes of [[Löwenstein-Jensen medium]]. From left to right:<br>- Negative control<br>- ''[[M. tuberculosis]]'': Dry-appearing colonies<br>- ''Mycobacterium avium complex'': Wet-appearing colonies<br>- ''[[M. gordonae]]'': Yellowish colonies]]

In the [[Runyon classification]] ,all threeboth bacteria are nonchromogens. They can be differentiated from ''M. tuberculosis'' and each other by commercially available [[DNA probes]].<ref name=Tropical>{{cite book|last1=Jones-Lopez|first1=Edward C.|last2=Ellner|first2=Jerrold J.|editor1-last=Guerrant|editor1-first=Richard L.|editor2-last=Walker|editor2-first=David H.|editor3-last=Weller|editor3-first=Peter F.|title=Tropical infectious diseases : principles, pathogens, & practice|date=2011|publisher=Saunders|___location=Edinburgh|isbn=9780702039355|edition=3rd|chapter=Chapter 35: Tuberculosis and Atypical Mycobacterial Infections}}</ref>{{rp|245}}

They are characterized as [[Gram-positive]], nonmotile, [[acid-fast]], short to long rods.{{cn|date=December 2022}}

'''Colony characteristics'''

* Usually, colonies are smooth, rarely rough, and not pigmented [[Colony (biology)|colonies]]. Older colonies may become yellow.

'''Physiology'''

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

'''Differential characteristics'''

* ''M. intracellulare'' and ''M. avium'' form the ''M. avium'' complex (MAC).

* Remarkable [[Internal transcribed spacer|ITS]] heterogeneity is seen within different ''M. intracellulare'' isolates.

==Type strainsSpecies ==

* ''[[Mycobacterium avium avium|Mycobacterium avium]]''

''M. intracellulare'' type strains include [[American Type Culture Collection|ATCC]] 13950, CCUG 28005, CIP 104243, DSM 43223, JCM 6384, and NCTC 13025.<ref>[http://bacdive.dsmz.de/index.php?search=8403&submit=Search Type strain of ''Mycobacterium intracellulare'' at Bac''Dive'' - the Bacterial Diversity Metadatabase]</ref>

** ''[[Mycobacterium avium subsp. paratuberculosis]]''

==Type strains==

''M. avium'' type strains include ATCC 25291, DSM 44156, and TMC 724.<ref>[http://bacdive.dsmz.de/index.php?site=search&rd=8419 Type strain of ''Mycobacterium avium'' at Bac''Dive'' - the Bacterial Diversity Metadatabase]</ref>

* ''M. intracellulare'' type strains include [[American Type Culture Collection|ATCC]] 13950, CCUG 28005, CIP 104243, DSM 43223, JCM 6384, and NCTC 13025.<ref>[http://bacdive.dsmz.de/index.php?search=8403&submit=Search Type strain of ''Mycobacterium intracellulare'' at Bac''Dive'' - the Bacterial Diversity Metadatabase]</ref>

* ''M. avium'' type strains include ATCC 25291, DSM 44156, and TMC 724.<ref>[http://bacdive.dsmz.de/index.php?site=search&rd=8419 Type strain of ''Mycobacterium avium'' at Bac''Dive'' - the Bacterial Diversity Metadatabase]</ref>

==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 chronic pulmonary diseaseCOPD 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 |last1=Riccardi |first1=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 |last2= |first2= |date=March 2017 |title=Etymologia: Mycobacterium chimaera |url=https://dx.doi.org/10.3201/eid2303.ET2303 |journal= Emerg Infect Dis |volume=23 |issue=3 |pages=499 |doi=10.3201/eid2303.ET2303 |access-date=March 14, 2017 |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>

==References==

{{reflistReflist}}

==External links==

* {{MeshName|Mycobacterium avium Complex}}

{{Gram-positive actinobacteria diseases}}

{{Mycobacteria}}

{{Taxonbar|from=Q3311330}}

{{DEFAULTSORT:Mycobacterium Intracellulare}}

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[[Category:Nontuberculous mycobacteria|avium complex]]

[[Category:Bacteria described in 1965]]

[[Category:Pathogenic bacteria]]