Mycobacterium intermedium

Mycobacterium intermedium is a species of the phylum Actinomycetota (Gram-positive bacteria with high guanine and cytosine content, one of the dominant phyla of all bacteria), belonging to the genus Mycobacterium.

Etymology: Latin; intermedium, meaning between, rapidly and slowly growing mycobacteria.

Description
Gram-positive, and nonmotile acid-fast coccobacilli (2.0 μm x 2.6 μm).

Colony characteristics
 * Eugonic, smooth and photochromogenic colonies (3–5mm in diameter) on Löwenstein-Jensen medium.

Physiology
 * Growth on Löwenstein-Jensen medium at 22 °C, 31 °C, 37 °C and 41 °C, (optimal temperature between 31 °C and 37 °C), within 2–3 weeks.
 * Susceptible to ethambutol and rifampin.
 * Resistant to isoniazid and streptomycin.

Differential characteristics
 * Phylogenetic position between rapidly and slowly growing mycobacteria.
 * M. asiaticum is phenotypically very similar, but can be distinguished by its growth at 22 °C, and by its dysgonic growth.

Pathogenesis

 * Pulmonary disease
 * Biosafety level 2

Type strain
Strain 1669/91 = ATCC 51848 = CCUG 37583 = CIP 104542 = DSM 44049 = JCM 13572
 * Repeatedly isolated from sputum from a patient with pulmonary disease.