Mycobacterium avium complex

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Mycobacterium avium complex
Scientific classification
Domain: Bacteria
Phylum: Actinobacteria
Order: Actinomycetales
Suborder: Corynebacterineae
Family: Mycobacteriaceae
Genus: Mycobacterium
Species complex: Mycobacterium avium complex
Binomial name
Mycobacterium intracellulare
Runyon 1965,[1] ATCC 13950
Mycobacterium avium
Chester 1901 emend. Thorel et al. 1990
Mycobacterium chimaera
Tortoli et al. 2004, CCUG 50989

Mycobacterium avium complex is a group of mycobacteria comprising Mycobacterium intracellulare, Mycobacterium avium, and Mycobacterium chimaera 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 or Mycobacterium avium complex infection.[2]


In the Runyon classification all three are nonchromogens. They can be differentiated from M. tuberculosis and each other via commercially available DNA probes.[3]:245

"Gram-positive", nonmotile and acid-fast short to long rods.

Colony characteristics

  • Usually smooth, rarely rough and nonpigmented colonies. Ageing colonies may become yellow.


Differential characteristics

  • M. intracellulare and Mycobacterium avium form the M. avium complex] (MAC).
  • Remarkable ITS heterogeneity within different M. intracellulare isolates.

Type strains[edit]

M. intracellulare type strains include ATCC 13950, CCUG 28005, CIP 104243, DSM 43223, JCM 6384, and NCTC 13025.[4]

M. avium type strains include ATCC 25291, DSM 44156, and TMC 724.[5]

M. chimaera type strains include DSM 44623 and CIP 107892.[6]

Human health[edit]

MAC infection can cause chronic pulmonary disease, lymphadenitis, and can cause disseminated disease, especially in people with immunodeficiency.[3]:245

The plant cannabinoid cannabigerol (CBG) have shown selective antimicrobial activity against Mycobacterium intracellulare with an IC50 value of 15.0 μg/mL.[7]


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, a mythological being made up of parts of 3 different animals.[8][9]


  1. ^ Runyon, E. 1965. Pathogenic mycobacteria. Advances in Tuberculosis Research, 14, 235-287.
  2. ^ "Mycobacterium Avium Complex. MAI; MAC Information". Patient Info. 29 August 2014. 
  3. ^ a b Jones-Lopez, Edward C.; Ellner, Jerrold J. (2011). "Chapter 35: Tuberculosis and Atypical Mycobacterial Infections". In Guerrant, Richard L.; Walker, David H.; Weller, Peter F. Tropical infectious diseases : principles, pathogens, & practice (3rd ed.). Edinburgh: Saunders. ISBN 9780702039355. 
  4. ^ Type strain of Mycobacterium intracellulare at BacDive - the Bacterial Diversity Metadatabase
  5. ^ Type strain of Mycobacterium avium at BacDive - the Bacterial Diversity Metadatabase
  6. ^ Type strain of Mycobacterium chimaera at BacDive - the Bacterial Diversity Metadatabase
  7. ^ Radwan, Mohamed M.; Ross, Samir A.; Slade, Desmond; Ahmed, Safwat A.; Zulfiqar, Fazila; ElSohly, Mahmoud A. (2008). "Isolation and Characterization of New Cannabis Constituents from a High Potency Variety". Planta Medica. 74 (3): 267–272. doi:10.1055/s-2008-1034311. ISSN 0032-0943. PMC 4887452Freely accessible. PMID 18283614. 
  8. ^ Henry, Ronnie (March 2017). "Etymologia: Mycobacterium chimaera". Emerg Infect Dis. 23 (3): 499. doi:10.3201/eid2303.ET2303. Retrieved March 14, 2017. Citing public domain text from the CDC. 
  9. ^ Tortoli, E; Rindi, L; Garcia, MJ; Chiaradonna, P; Dei, R; Garzelli, C; Kroppenstedt, RM; Lari, N; Mattei, R; Mariottini, A; Mazzarelli, G; Murcia, MI; Nanetti, A; Piccoli, P; Scarparo, C (July 2004). "Proposal to elevate the genetic variant MAC-A, included in the Mycobacterium avium complex, to species rank as Mycobacterium chimaera sp. nov". International Journal of Systematic and Evolutionary Microbiology. 54 (Pt 4): 1277–85. doi:10.1099/ijs.0.02777-0. PMID 15280303. 

External links[edit]