Mycobacterium avium subsp. hominissuis (MAH) is a widespread opportunistic pathogen that can be isolated from
environment (dust, soil and water) and patients with lung or lymphnode infection. In our previous research we
revealed the pronounced genetic diversity in MAH by identifying eight different types of a newly described
genomic island. In order to identify mechanisms of such horizontal gene transfer we now analyzed the ability of
47 MAH isolates to inherit the conjugative plasmid pRAW from M. marinum. A higher percentage of environmental isolates (22.7%) compared to clinical isolates (8%) had the capacity to function as recipient in conjugal
plasmid transfer. Genetic analysis showed additionally that environmental isolates contained more genes
homologous to genes present on conjugative mycobacterial plasmids than clinical isolates. Comparative analysis
of the genomes of the isolates pointed to a possible association between the ability to act as recipient in conjugation and the structure of a genomic region containing the radC gene and a type I restriction/modification
system. Finally we found that uptake of pRAW decreased the resistance against various antibiotics.