Mycobacterium intracellulare

Mycobacterium intracellulare

Description
Gram-positive, nonmotile and acid-fast short to long rods.

Colony characteristics
 * Usually smooth, rarely rough and nonpigmented colonies. Ageing colonies may become yellow.

Physiology
 * Growth on Löwenstein-Jensen medium and Middlebrook 7H10 at 37°C after 7 or more days.
 * Resistant to isoniazid, ethambutol, rifampin and streptomycin.

Differential characteristics
 * M. intracellulare and M. avium form the M. avium-intracellulare complex (MAIC). A commercially available hybridisation assay (AccuProbe) to identify all members of the MAIC exists. Furthermore, separate AccuProbes are available to identify either M. intracellulare or M. avium.
 * remarkable ITS heterogeneity within different M. intracellulare isolates.

Pathogenesis

 * Most frequently encountered in pulmonary secretions from patients suffering from tuberculosis like disease and from surgical specimens from such patients.
 * When isolated from human secretions, it is often the etiologic agent of pulmonary disease, although frequently isolated as apparent casual resident
 * Biosafety level 2

Type Strain
Strain ATCC 13950 = CCUG 28005 = CIP 104243 = DSM 43223 = JCM 6384 = NCTC 13025.
 * First isolated from fatal systemic disease in a child. Found in soil and water.