Mycobacterium tusciae

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.

Differential characteristics
 * Closely related to Mycobacterium aichiense and Mycobacterium farcinogenes, rapidly-growing mycobacteria, by evaluation of 16S rDNA sequences.

Pathogenesis

 * Probably an opportunistic pathogen. 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.

Type Strain

 * Strain FI-25796 = CCUG 50996 = CIP 106367 = DSM 44338 = JCM 12692.