Mycobacterium gastri

Mycobacterium gastri 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.

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

Colony characteristics
 * Nonchromogenic, smooth to rough, white colonies on Löwenstein-Jensen medium and smooth or somewhat granular on Middlebrook 7H10 agar.

Physiology
 * Growth on Löwenstein-Jensen medium or on Middlebrook 7H10 agar at 37 °C, (temperature range 25 °C-40 °C), within 7 or more days.
 * Does not grow in the presence of ethambutol or isoniazid.

Differential characteristics
 * Closely related to M. kansasii
 * M. gastri and M. kansasii share an identical 16S rDNA sequence. Species differentiation is possible by differences in the ITS and hsp65 sequences.
 * M. kansasii produces a photochromogenic yellow pigment.
 * AccuProbes for M. kansasii are negative.

Pathogenesis

 * Casual resident of human stomachs, but not considered a cause of disease.
 * Biosafety level 1

Type strain
Strain ATCC 15754 = CCUG 20995 = CIP 104530 = DSM 43505 = JCM 12407.
 * First isolated from human gastric specimen. Also found in soil.