[Identification of Mycobacterium avium complex isolated in Tokyo University Hospital using DNA probe procedure]

Mycobacteria other than Mycobacterium tuberculosis isolated in Tokyo University Hospital during 1970-1980 were identified to the level of species using a commercial DNA probe Kit (Gen-Probe Rapid Diagnostic System for Mycobacterium avium Complex; Gen-Probe Corp., California, USA). The cell count to give a positive result, that is, the absolute hybridization of more than 10%, was 5 X 10(6) CFU/ml for M. avium and 1 X 10(6) CFU/ml for M. intracellulare, respectively. At this condition, compared with the conventional biochemical test, the DNA prove procedure showed sensitivity of 98.8% and specificity 100%. The agreement of the identification between the two methods was 99.1%. The isolation frequency at the level of species among 104 isolates tested in this method was: M. avium 72.1%, M. kansaii 7.7%, M. intracellulare 3.8%, M. gordonae 3.8% and others 12.5%. Thus, this DNA probe test to identify and distinguish M. avium complex gave a satisfactory result in its simplicity and accuracy.