Mycobacterium nebraskense

Mycobacterium nebraskense is a slowly growing yellow pigmented mycobacterium that was first isolated from human sputum in Nebraska, USA. Etymology: nebraskense, referring to the State of Nebraska, USA.

Description
Microscopy
 * Cells are non-spore-forming rods that stain acid-fast.

Colony characteristics
 * Mature colonies are rough with an elevated centre and produce strong yellow pigmentation in the dark.

Physiology
 * Mature growth is produced in 3 weeks on Middlebrook 7H10 medium and in 4 or more weeks on LJ medium at 25–35 C,
 * Optimal growth at 30–35C and no growth at 42C.

Differential characteristics
 * The organism has unique Mycobacterium sequences for the 16S rRNA gene and ITS1 region targets.
 * Phylogenetic analysis using 16S rRNA gene sequences shows that M. nebraskense belongs to the slowly growing mycobacteria and is closely related to Mycobacterium kansasii, Mycobacterium scrofulaceum, Mycobacterium malmoense and Mycobacterium avium.
 * The organism is positive for heat-stable catalase and negative for nitrate reductase, urease activity, niacin accumulation, arylsulfatase activity at 3 days and pyrazinamidase production.
 * Less than 45 mm foam is produced in the semi-quantitative catalase test and variable results are indicated for Tween 80 hydrolysis. *Growth is inhibited on MacConkey agar without crystal violet and by the addition of 5%NaCl to the culture medium.

Pathogenesis

 * Isolated from five different patients with symptomatic pulmonary infections.

Type Strain

 * Strain UNMC-MY 1349 = ATCC BAA-837 = DSM 44803.