J. Kolb* 1 , D. Hillemann 1 , J. Reetz 2 , S. Rüsch-Gerdes 1 , E. Richter 1 1 Forschungszentrum Borstel, Nationales Referenzzentrum für Mykobakterien, Borstel, Deutschland 2 Bundesinstitut für Risikobewertung, Berlin, Deutschland Introduction: One of the most frequent isolated species within nontuberculous mycobacteria is M. avium, which is ubiquitously found in the environment and has been shown to be responsible for a variety of human diseases, mainly in immunocomprised patients, but also in patients with no obvious immune deficiencies.