IS1245 RFLP-based genotyping study of Mycobacterium avium subsp. hominissuis isolates from pigs and humans.

Mycobacterium avium subsp. hominissuis, ubiquitous environmental mycobacterium, is an opportunistic pathogen that is regularly isolated from pigs and humans in Slovenia. Genetic diversity of 114 isolates from pigs (n = 57) and humans (n = 57), identified by means of bacteriology, DNA-RNA hybridization techniques, IS901 PCR and IS1245 PCR, was investigated in this study, using IS1245 restriction fragment length polymorphism (RFLP) analysis. Identical IS1245 RFLP profiles were found in isolates from pigs, isolates from humans and isolates from both origins. The proportion of clustered isolates varied as it depended on the similarity level (100% and 75%) chosen for the cluster limits. Using IS1245 RFLP, it was possible to detect monoclonal, polyclonal and recent infections and to monitor the genetic variability of the strains from individual patients. Our findings indicate the environment as the source of infection for both pigs and humans. The questions about the possibility of intra- and inter-species transmission of infection remain to be answered.