Health Dictionary
Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.
Mycobacterium genavense
Introduction
Mycobacterium genavense
Description
Description
A slow-growing subspecies of Mycobacterium.
Gram-positive, and nonmotile acid-fast coccobacilli (1.0µm x 2.0µm). 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.
Pathogenesis
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.
Type Strain
Type Strain
Strain 2289 = ATCC 51234
Treatment
Treatment
Antimicrobial regimen
- M. genavense isolates [1]
- Susceptibility: Amikacin, Rifamycin, Fluoroquinolones, Streptomycin, and Macrolides
- NOTE(1): Ethambutol has limited activity
- NOTE(2): Optimal therapy is not determined, but multidrug therapies including Clarithromycin appear to be more effective than those without Clarithromycin
References
References
- ↑ Griffith, David E.; Aksamit, Timothy; Brown-Elliott, Barbara A.; Catanzaro, Antonino; Daley, Charles; Gordin, Fred; Holland, Steven M.; Horsburgh, Robert; Huitt, Gwen; Iademarco, Michael F.; Iseman, Michael; Olivier, Kenneth; Ruoss, Stephen; von Reyn, C. Fordham; Wallace, Richard J.; Winthrop, Kevin; ATS Mycobacterial Diseases Subcommittee; American Thoracic Society; Infectious Disease Society of America (2007-02-15). “An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases”. American Journal of Respiratory and Critical Care Medicine. 175 (4): 367–416. doi:10.1164/rccm.200604-571ST. ISSN 1073-449X. PMID 17277290.
- Böttger et al. 1993. Mycobacterium genavense sp. nov. Int. J. Syst. Bacteriol., 43, 841-843.
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]