Mycobacterium tusciae

Mycobacterium tusciae
Scientific classification
Domain:	Bacteria
Phylum:	Actinomycetota
Class:	Actinomycetia
Order:	Mycobacteriales
Family:	Mycobacteriaceae
Genus:	Mycobacterium
Species:	M. tusciae
Binomial name
Mycobacterium tusciae Tortoli et al. 1999, DSM 44338

Mycobacterium tusciae is a slow-growing, scotochromogenic mycobacterium first isolated from a lymph node of an immunocompromised child and subsequently from tap water and from a respiratory specimen of a patient with chronic fibrosis. Etymology: tusciae referring to the Italian region of Tuscany, where the organisms were first isolated.

Description

Microscopy

• Gram-positive, nonmotile and acid-fast rods.
• Early
  microscopic
  morphology on Middlebrook 7H11 agar is characterized by a very elevated centre surrounded by an uneven flat fringe.

Colony characteristics

• Colonies are rough and strongly yellow-pigmented.

Physiology

• Slow growth on
  Löwenstein-Jensen
  medium at temperatures between 25 °C and 32 °C within 4 weeks.
• Growth at 37 °C is inconsistent and requires longer incubation.
• No growth at 42 °C and on MacConkey agar.
• The type strain is susceptible in vitro to ciprofloxacin, clarithromycin, rifabutin, rifampicin, sparfloxacin and

streptomycin.

• Inhaled
  silica
  , (asbestos) can also be a cause.

Pathophysiology

• The lymph nodes irritation causes a response by the
  macrophages
  , which cause enzymes, complement proteins, and regulatory factors such as interleukin-1 to get produced.
• The
  macrophages
  also carry receptors for lymphokines, and lymphokines act as cytokines which further attract T cells, B cells and natural killer cells. The damage produced by the immune response causes the lung tissue to inflame, expand, and swell with fluid then leak.
• macrophages
  .
• Macrophages
  continue to attempt to remove the foreign substance, and unless the silica is removed by mechanical expulsion means of coughing, the immune response continues.
• Continued immune attack by the
  macrophages results in silicosis, which repeated relapses making the condition chronic. Exposed people usually remain asymptomatic long after the nodules are apparent on chest radiography
  .

• Tortoli E., 1999. Mycobacterium tusciae sp. nov. Int. J. Syst. Bacteriol., 49, 1839–1844.
  PMID 10555367

External links

• Type strain of Mycobacterium tusciae at BacDive - the Bacterial Diversity Metadatabase

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