Nontuberculous mycobacteria (NTM) are environmental opportunistic pathogens. They are non-sporulating, non-mobile, aerobic bacteria. As all mycobacteria, NTM have in the cell wall mycolic acid, which impart mycobacteria with unique properties. Mycobacteria from Mycobacterium avium complex (MAC) and Mycobacterium abscessus complex (MABSC) are the most frequent cause of mycobacteriosis in the world. In the last few years taxonomy in MAC and MABSC was rapidly changing due to new molecular methods that are able to differentiate between species. New techniques are able to identify Mycobacterium chimaera that was previously recognized as Mycobacterium intracellulare and also differentiate subspecies of MABSC. Due to their natural habitat, NTM are constantly exposed to various concentrations of antimicrobial drugs and other chemicals and consequently they had developed different resistance mechanisms. Macrolides and aminoglycosides are frequently used drugs to treat MAC and MABSC infections. One hundred and thirty-nine Slovenian mycobacteria isolates obtained from National collection of mycobacterial isolates from Klinika Golnik that belong to MAC and MABSC were analysed. GenoType NTM-DR (Hain Lifescience GmbH) was used to differentiate M. intracellulare from M. chimaera and subspecies of MABSC. Not only species identification but also information about mutation in genes that confer resistance against macrolides and aminoglycosides, was obtained. ERIC-PCR was tested on some isolates of MAC and MABSC for its ability to differentiate different isolates and strains. Results showed that 48,5% of previously identified
M. intracellulare were actually recognised as M. chimaera and that M. abscessus subsp. abscessus is the most frequent subspecies of MABSC. Most of the MABSC isolates were resistant to macrolides, however none of the isolates of MAC and MABSC had mutations in genes for aminoglycoside resistance. Results obtained with ERIC-PCR showed that the method is able to differentiate isolates and strains of MAC and MABSC.