Mycobacterium intermedium sp. nov.

Strains of a new type of slowly growing mycobacterium were repeatedly isolated from sputum from a patient with pulmonary disease. This photochromogenic organism grew at 22, 31, 37, and 41 degrees C, possessed catalase, acid phosphatase, esterase, beta-galactosidase, and arylsulfatase activities, and hydrolyzed Tween. It did not produce nicotinic acid or have nitrate reductase, acetamidase, benzamidase, isonicotinamidase, nicotinamidase, pyrazinamidase, succinidamidase, and acid phosphatase activities. Urease activity was variable. The organism is susceptible to ethambutol and resistant to isoniazid and streptomycin. A mycolic acid analysis revealed the presence of alpha-mycolates, alpha'-mycolates, and keto-mycolates. The results of comparative 16S rRNA sequencing placed this organism at an intermediate position between the rapidly and slowly growing mycobacteria. On the basis of the pattern of enzymatic activities and metabolic properties, the results of fatty acid analyses, and the unique 16S rRNA sequence, we propose that this organism represents a new species, for which we propose the name Mycobacterium intermedium. The type strain is strain 1669/91; a culture of this strain has been deposited in the Deutsche Sammlung von Mikroorganismen und Zellkulturen as strain DSM 44049.