Mycobacterium genavense
Encyclopedia
Description
A slow-growing subspeciesSubspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of Mycobacterium
Mycobacterium
Mycobacterium is a genus of Actinobacteria, given its own family, the Mycobacteriaceae. The genus includes pathogens known to cause serious diseases in mammals, including tuberculosis and leprosy...
.
Nonmotile, acid-fast
Acid-fast
Acid-fastness is a physical property of certain bacteria, specifically their resistance to decolorization by acids during staining procedures.Acid-fast organisms are difficult to characterize using standard microbiological techniques Acid-fastness is a physical property of certain bacteria,...
coccobacilli (1.0 µm x 2.0 µm). No formation of spores, capsules or aerial hyphae.
Colony characteristics
- Tiny, transparent, nonphotochromogenic and dysgonic coloniesColony (biology)In biology, a colony reference to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defense or the ability to attack bigger prey. Some insects live only in colonies...
(on solid Middlebrook 7H11 medium MJ (Allied Laboratories).
Physiology
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...
- 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 streptomycinStreptomycinStreptomycin is an antibiotic drug, the first of a class of drugs called aminoglycosides to be discovered, and was the first antibiotic remedy for tuberculosis. It is derived from the actinobacterium Streptomyces griseus. Streptomycin is a bactericidal antibiotic. Streptomycin cannot be given...
and rifampicinRifampicinRifampicin or rifampin is a bactericidal antibiotic drug of the rifamycin group. It is a semisynthetic compound derived from Amycolatopsis rifamycinica ... - Resistant to isoniazidIsoniazidIsoniazid , also known as isonicotinylhydrazine , is an organic compound that is the first-line antituberculosis medication in prevention and treatment. It was first discovered in 1912, and later in 1951 it was found to be effective against tuberculosis by inhibiting its mycolic acid...
and ethambutolEthambutolEthambutol is a bacteriostatic antimycobacterial drug prescribed to treat tuberculosis. It is usually given in combination with other tuberculosis drugs, such as isoniazid, rifampicin and pyrazinamide....
Differential characteristics
- Differentiation from other slowly growing mycobacteria by its fastidious growth.
- Closely related to M. simiae by evaluation of 16S rDNA sequences.
Pathogenesis
- Opportunistic pathogenPathogenA pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
. Clinically indistinguishable from generalised infections in patients with AIDSAIDSAcquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...
due to M. avium complex strains, but more related to gastro-intestinal disorders. - Most common cause of mycobacterial disease in parrots and parakeets.