[A taxonomic study on a mycobacterium which caused a skin ulcer in a Japanese girl and resembled Mycobacterium ulcerans]

Abstract

A taxonomic study has been made on a mycobacterial strain isolated from skin ulcer lesion of a 19 year-old Japanese girl who has lived only in Japan. By numerical classification, in which 108 characters were used, 6 isolates of this strain formed one cluster together with Mycobacterium ulcerans strains. However, the isolates were distinguished from the M. ulcerans strains, forming a subcluster. The isolates were differentiated by the characters shown in Table 2 from authentic M. ulcerans strains. The mycolic acids of the strain ATCC 33788 isolated from Japanese girl were distinguished from those of the type strain ATCC 19423 of M. ulcerans. The number of carbon atoms of alpha-mycolate of the former centered at 80, whereas those of the strain ATCC 19423 at 76. The number of carbon atoms of the alpha-unit was 24 in both strains and the number of double bonds was 2 in both strains. The strain ATCC 33788 showed a 100% similarity with the strain ATCC 19423 in DNA hybridization. In view of the above results, we have concluded that the strain belongs to a new subspecies of M. ulcerans (M. ulcerans subsp. shinshuense). Until now, M. ulcerans infection has occurred only in three area of the world, Africa, Oceania, and South and Middle America. Our case is the first case of M. ulcerans infection discovered in an area other than the above. However, the strain was not the same as the M. ulcerans described previously but differed from it in mycolic acids and some biological and biochemical characteristics.