Mycobacterium genavense
Mycobacterium genavense is a slow-growing species of the phylum Actinomycetota, belonging to the genus Mycobacterium.
Description
Nonmotile, acid-fast coccobacilli. No formation of spores, capsules or aerial hyphae.Colony characteristics
- Tiny, transparent, nonphotochromogenic and dysgonic colonies.
- 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
- Differentiation from other slowly growing mycobacteria by its fastidious growth.
- Closely related to M. simiae by evaluation of 16S rDNA sequences.
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.