Mycobacterium terrae

Mycobacterium terrae is a slow-growing species of Mycobacterium. 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'. Richmond and Cummings were the first to isolate Mycobacterium terrae, which they described as 'an acid‐fast saprophyte'. It is sometimes called the “radish bacillus', because it was isolated from radish water. This bacterium was originally injected into guinea pigs, 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.