Mycobacterium alvei sp. nov.

A new species of rapidly growing, nonphotochromogenic mycobacteria, Mycobacterium alvei, is described. The inclusion of this organism in the genus Mycobacterium is based on its acid fastness, its mycolate pattern, and its G+C content. A study of six strains showed that they form a homogeneous group with an internal phenotypic similarity value of 97 ± 2.22%. DNA relatedness studies showed that the six M. alvei strains which we studied form a single DNA hybridization group which is less than 49% related to 14 other species of the genus Mycobacterium; the ΔT(m) values determined for the strains which exhibited higher levels of DNA homology were all greater than 7.9°C. A lipid analysis showed that tuberculostearic acid was present. Docosanoic and tetracosanoic acid methyl esters were detected as mycolic acid cleavage products. All six isolates which we tested contained α-mycolic acids and relatively large amounts of a new kind of mycolic acid containing a methoxy group at ω-1 position, a characteristic that has not been described previously in mycobacteria. Strain CR-21 is the type strain; a culture of this strain has been deposited in the Collection Nationale de Cultures de Microorganismes de l'Institut Pasteur, Paris, France, as strain CIP 103464.