Mycobacterium terrae is a slow-growing species of Mycobacterium

Mycobacterium

Mycobacterium is a genus of Actinobacteria, given its own family, the Mycobacteriaceae. The genus includes pathogens known to cause serious diseases in mammals, including tuberculosis and leprosy...

. It is an ungrouped member of the third Runyon (nonchromatogenic mycobacteria). It is known to cause serious skin infections, which are "relatively resistant to antibiotic therapy".

Discovery

Richmond and Cummings were the first to isolate Mycobacterium terrae, which they described it as an "an acid‐fast saprophyte". It is sometimes called the “radish bacillus", because it was isolated from radish water.

Pathology

This bacterium was originally injected into guinea pig

Guinea pig

The guinea pig , also called the cavy, is a species of rodent belonging to the family Caviidae and the genus Cavia. Despite their common name, these animals are not in the pig family, nor are they from Guinea...

s, and did not cause apparent illness, leading to the misconception that this strain was nonpathogenic. In reality, however, infection by this organism can cause disease of the joints, tendons, lungs, gastrointestinal tract, and genitourinary tract. In humans, symptoms of infection include swelling, lesions, and inflammation, and may mimic the symptoms of osteoarthritis

Osteoarthritis

Osteoarthritis also known as degenerative arthritis or degenerative joint disease, is a group of mechanical abnormalities involving degradation of joints, including articular cartilage and subchondral bone. Symptoms may include joint pain, tenderness, stiffness, locking, and sometimes an effusion...

.

Uses

This bacterium is used to study effectiveness of cleaning processes for reusable medical instruments.