Typing of clinical Mycobacterium avium complex strains cultured during a 2-year period in Denmark by using IS1245

In the present study restriction fragment length polymorphism analyses with the recently described insertion sequence IS1245 as a probe was performed with clinical Mycobacterium avium complex strains cultured in Denmark durin g a 2-year period. The overall aim of the study was to disclose potential r outes of transmission of these microorganisms. As a first step, the genetic diversity among isolates from AIDS patients and non-human immunodeficiency virus (HIV)-infected patients was described. In addition, a number of isol ates from nonhuman sources cultured during the same period were analyzed an d compared to the human isolates. ri total of 203 isolates from AIDS patien ts (n = 90), non-HIV-infected patients (n = 91), and nonhuman sources (n = 22) were analyzed. The presence of IS1245 was restricted to Mycobacterium a vium subsp, avium isolates. The majority of human isolates had large number s of IS1245 copies, while nonhuman isolates could be divided into a high-co py-number group and a low-copy-number group. Groups of identical strains we re found to be geographically widespread, comprising strains from AIDS pati ents as Hell as strains from non-HIV-infected patients, Samples of peat (to be used as potting soil) and veterinary samples were found to contain viab le M avium isolates belonging to genotypes also found in humans.