Mycobacterium gastri

Mycobacterium gastri is a species of the phylum actinobacteria (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, 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 an etiologic agent of disease.
• Biosafety level 1

Type strain

• First isolated from human gastric specimen. Also found in soil.

Strain ATCC 15754 = CCUG 20995 = CIP 104530 = DSM 43505 = JCM 12407.

References

• Wayne,L. 1966. Classification and identification of mycobacteria. III. Species within Group III. American Review of Respiratory Diseases, 93, 919-928.]