2 MARKERS, IS901-IS902 AND P40, IDENTIFIED BY PCR AND BY USING MONOCLONAL-ANTIBODIES IN MYCOBACTERIUM-AVIUM STRAINS

The occurrence of two markers, a newly identified 40-kDa protein (p40) and the insertion sequence IS901-IS902, in strains of Mycobacterium a vium subspp, was evaluated, Analysis of 184 type and field strains of the M. avium complex from human, animal, and environmental sources by PCR specific to IS901 and by a monoclonal antibody specific to p40 dem onstrated the presence of the two molecular markers in all of the M. a vium subsp, silvaticum strains examined and also in a number of M. avi um subsp, avium strains (the latter isolated mainly from pigs). The ap pearance of the two markers was completely concurrent in all strains, Further, the marker-positive M. avium subsp. avium strains were mainly serotype 2, whereas M. avium complex strains of serotypes 4, 6, 8, 9, and 10 were marker negative. The M. avium subsp, avium type strain AT CC 25291 and approximately 50% of the M. avium subsp, avium held strai ns isolated from animals contained the markers, while only one strain of human origin was found to be marker positive. Therefore, IS901 and p40 appear to have substantial potential to differentiate among isolat es of the M. avium complex, This observation raises new issues regardi ng classification of strains, since the presence of the markers was fo und to be inconsistent with the present taxonomic grouping of M. avium subspp.