| Резюме: | <p>Abstract</p> <p>Background</p> <p>Most of environmental mycobacteria have been previously demonstrated to resist free-living amoeba with subsequent increased virulence and resistance to antibiotics and biocides. The <it>Mycobacterium avium </it>complex (MAC) comprises of environmental organisms that inhabit a wide variety of ecological niches and exhibit a significant degree of genetic variability. We herein studied the intra-ameobal location of all members of the MAC as model organisms for environmental mycobacteria.</p> <p>Results</p> <p>Type strains for <it>M. avium</it>, <it>Mycobacterium intracellulare</it>, <it>Mycobacterium chimaera</it>, <it>Mycobacterium colombiense</it>, <it>Mycobacterium arosiense</it>, <it>Mycobacterium marseillense</it>, <it>Mycobacterium timonense </it>and <it>Mycobacterium bouchedurhonense </it>were co-cultivated with the free-living amoeba <it>Acanthamoeba polyphaga </it>strain Linc-AP1. Microscopic analyses demonstrated the engulfment and replication of mycobacteria into vacuoles of <it>A. polyphaga </it>trophozoites. Mycobacteria were further entrapped within amoebal cysts, and survived encystment as demonstrated by subculturing. Electron microscopy observations show that, three days after entrapment into <it>A. polyphaga </it>cysts, all MAC members typically resided within the exocyst.</p> <p>Conclusions</p> <p>Combined with published data, these observations indicate that mycobacteria are unique among amoeba-resistant bacteria, in residing within the exocyst.</p>
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