Relationship between IS901 in the Mycobacterium avium complex strains isolated from birds, animals, humans, and the environment and virulence for poultry

A total of 738 strains of Mycobacterium avium complex (MAC) were examined i n biological experiments on poultry by use of PCR methods with primers for detection of the insertion sequence IS901. Serotype strains of MAC from all known 28 serotypes were examined. Further strains were isolated from human immunodeficiency virus (HIV)-negative and HIV-positive patients, 6 animal species, 17 bird species, and the environment. Of 165 strains virulent for poultry, characterized by generalized tuberculosis, 164 strains contained I S901, a result which is statistically highly significant (P, 0.01). The rem aining 573 strains were nonvirulent; however, IS901 was present in 24 strai ns. From among 20 strains of serotypes 1, 2, and 3, IS901 was found in 15 s trains, only 5 of which were virulent for poultry. The remaining 111 strain s, of serotypes 4 to 28, were nonvirulent and did not incorporate IS901. No ne of the 152 strains isolated from humans was virulent for poultry, includ ing 12 strains which were IS901 positive.