Abstract
Aim. To study ultrastructural changes of hemolytic and enterohemorrhagic Escherichia coli during interaction with metabolites of Lactobacillus fermentum . Materials and methods. Strains of pathogenic hemolytic (Hly) and enterohemorrhagic Escherichia coli (O157:H7) as well as symbiotic bacteriocinogenic strain Lactobacillus fermentum 97 were used. Inhibition of growth of viable cells was performed by delayed antagonism method. Using electron microscopy, assessment of ultrastructural changes of hemolytic and enterohemorrhagic E.coli under the influence of diffusing in MPC-agar metabolites of lactobacilli. Results. Changes pointing to profound destructive processes in bacterial cells were detected on ultrathin sections. Under the influence of diffusing metabolites of lactobacilli, the following changes were observed: destabilization of cell wall, expansion of periplasmatic space, and emergence of low electron density areas of cytoplasm in polar sections of cells with visualization of floccular material. Emergence of elongated paracrystallic packings and filamentous structures of different length, which deserve special study, was observed in cells of hemolytic E.coli . Conclusion. Bacteriocin-like products of lactobacilli during interaction with pathogenic E.coli cause profound destructive changes in the latter which lead to destruction of target cells.
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