Mycobacterium genavense is a slow-growing species of the phylum

Actinomycetota The Actinomycetota (or Actinobacteria) are a diverse phylum of Gram-positive bacteria with high GC content. They can be terrestrial or aquatic. They are of great importance to land flora because of their contributions to soil systems. In soil t ...

(

Gram-positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. The Gram stain is ...

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

with high guanine and cytosine content, one of the dominant phyla of all bacteria), belonging to the genus ''

Mycobacterium ''Mycobacterium'' is a genus of over 190 species in the phylum Actinomycetota, assigned its own family, Mycobacteriaceae. This genus includes pathogens known to cause serious diseases in mammals, including tuberculosis (''Mycobacterium tuberculo ...

''.

Description

Nonmotile,

acid-fast Acid-fastness is a physical property of certain bacterial and eukaryotic cells, as well as some sub-cellular structures, specifically their resistance to decolorization by acids during laboratory staining procedures. Once stained as part of a sa ...

coccobacilli Bacterial cellular morphologies are the shapes that are characteristic of various types of bacteria and often key to their identification. Their direct examination under a light microscope enables the classification of these bacteria (and archaea ...

(1.0

μm The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...

x 2.0 μm). No formation of

spores In biology, a spore is a unit of sexual (in fungi) or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plant ...

, capsules or aerial

hyphae A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

. Colony characteristics *Tiny, transparent, nonphotochromogenic and dysgonic

colonies A colony is a territory subject to a form of foreign rule, which rules the territory and its indigenous peoples separated from the foreign rulers, the colonizer, and their '' metropole'' (or "mother country"). This separated rule was often or ...

(on solid Middlebrook 7H11 medium MJ (Allied Laboratories).

Physiology Physiology (; ) is the science, scientific study of function (biology), functions and mechanism (biology), mechanisms in a life, living system. As a branches of science, subdiscipline of biology, physiology focuses on how organisms, organ syst ...

*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 A blood culture is a medical laboratory test used to detect bacteria or fungi in a person's blood. Under normal conditions, the blood does not contain microorganisms: their presence can indicate a bloodstream infection such as bacteremia or fu ...

medium, Middlebrook 7H9 medium. *Acid broth media such as,

BACTEC pyrazinamidase test medium A blood culture is a medical laboratory test used to detect bacteria or fungi in a person's blood. Under normal conditions, the blood does not contain microorganisms: their presence can indicate a bloodstream infection such as bacteremia or fu ...

, 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 Streptomycin is an antibiotic medication used to treat a number of bacterial infections, including tuberculosis, Mycobacterium avium complex, ''Mycobacterium avium'' complex, endocarditis, brucellosis, Burkholderia infection, ''Burkholderia'' i ...

and

rifampicin Rifampicin, also known as rifampin, is an ansamycin antibiotic used to treat several types of bacterial infections, including tuberculosis (TB), ''Mycobacterium avium'' complex, leprosy, and Legionnaires' disease. It is almost always used tog ...

*Resistant to

isoniazid Isoniazid, also known as isonicotinic acid hydrazide (INH), is an antibiotic used for the treatment of tuberculosis. For active tuberculosis, it is often used together with rifampicin, pyrazinamide, and either streptomycin or ethambutol. F ...

Differential characteristics *Differentiation from other slowly growing mycobacteria by its fastidious growth. *Closely related to ''M. simiae'' by evaluation of

16S rDNA 16S ribosomal RNA (or 16 S rRNA) is the RNA component of the 30S subunit of a prokaryotic ribosome (SSU rRNA). It binds to the Shine-Dalgarno sequence and provides most of the SSU structure. The genes coding for it are referred to as 16S rRNA ...

sequences.

Pathogenesis

*Opportunistic

pathogen In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory of d ...

. Clinically indistinguishable from generalised infections in patients with

AIDS The HIV, human immunodeficiency virus (HIV) is a retrovirus that attacks the immune system. Without treatment, it can lead to a spectrum of conditions including acquired immunodeficiency syndrome (AIDS). It is a Preventive healthcare, pr ...

due to

M. avium complex ''Mycobacterium avium ''complex is a group of mycobacteria comprising ''Mycobacterium intracellulare'' and ''Mycobacterium avium'' that are commonly grouped because they infect humans together; this group, in turn, is part of the group of nontub ...

strains, but more related to gastro-intestinal disorders. *Most common cause of mycobacterial disease in

parrots Parrots (Psittaciformes), also known as psittacines (), are birds with a strong curved beak, upright stance, and clawed feet. They are classified in four families that contain roughly 410 species in 101 genus (biology), genera, found mostly in ...

and

parakeets A parakeet is any one of many small- to medium-sized species of parrot, in multiple genera, that generally has long tail feathers. Etymology and naming The name ''parakeet'' is derived from the French word ''perroquet'', which is reflect ...

Type strain

Strain 2289 = ATCC 51234

References

*Böttger et al. 1993. Mycobacterium genavense sp. nov. Int. J. Syst. Bacteriol., 43, 841–843. Acid-fast bacilli genavense Bacteria described in 1993 {{Mycobacterium-stub