Distribution of serotypes, IS901 and a 40 kDa protein in Mycobacterium avium complex strains isolated from man and animals in Denmark.

The aim of the present study was to characterize all strains of the Mycobacterium avium complex isolated in Denmark in 1993. A total of 141 M. avium complex strains (86 from man, 38 from animals, and 17 from peat) were analysed by serotyping, ELISA specific for a 40 kDa protein, and IS901-specific PCR. Serotype analysis showed that the most frequent serotypes among human strains were serotype 4 (27%) and serotype 6 (19%), which differs from an earlier survey where serotype 1 was most prevalent. The most frequent serotypes in animals were serotype 2 (53%) and serotype 6 (13%), whereas the most prevalent serotypes among strains isolated from peat were serotype 4 (29%) and serotype 9 (18%). There was a concurrent appearance of IS901 and p40 in all strains. Only M. avium complex strains isolated from animals, and belonging to serotype 1 or serotype 2, contained the IS901/p40 markers. The different distribution of serotypes of M. avium complex strains in animals and man, and the presence of IS901/p40 exclusively in animal strains, suggests that transmission of M. avium from animals to man is not of significance in Denmark.