Mycobacterium genavense

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Mycobacterium genavense

Scientific classification

Kingdom:	Bacteria
Phylum:	Actinobacteria
Order:	Actinomycetales
Suborder:	Corynebacterineae
Family:	Mycobacteriaceae
Genus:	Mycobacterium
Species:	M. genavense

Binomial name

Mycobacterium genavense
Böttger et al. 1993, ATCC 51234

Mycobacterium genavense

1 Description
2 Pathogenesis
3 Type Strain
4 References

[edit] Description

A slow-growing subspecies of Mycobacterium.

Nonmotile, acid-fast coccobacilli (1.0 µm x 2.0 µm). No formation of spores, capsules or aerial hyphae.

Colony characteristics

Tiny, transparent, nonphotochromogenic and dysgonic colonies (on solid Middlebrook 7H11 medium MJ (Allied Laboratories).

Physiology

Slow, fastidious growth in liquid media within 3-12 weeks at 31°C, 37°C and 42°C, with slightly better growth at 45°C.
Primary cultures for isolation require liquid broth media such as BACTEC 12B medium, Middlebrook 7H9 medium.
Acid broth media such as,BACTEC pyrazinamidase test medium, may facilitate primary isolation.
No growth on standard solid media like Löwenstein-Jensen, unsupplemented Middlebrook 7H11 or Middlebrook 7H10 media.
Visible growth on solid Middlebrook 7H11 medium supplemented with MJ after inoculation with a broth culture within 3–9 weeks.
Susceptible to streptomycin and rifampicin
Resistant to isoniazid and ethambutol

Differential characteristics

Differentiation from other slowly growing mycobacteria by its fastidious growth.
Closely related to M. simiae by evaluation of 16S rDNA sequences.

[edit] Pathogenesis

Opportunistic pathogen. Clinically indistinguishable from generalised infections in patients with AIDS due to M. avium complex strains, but more related to gastro-intestinal disorders.
Most common cause of mycobacterial disease in parrots and parakeets.