Biofilms are communities of bacterial cells that live attached to a surface in moist
environments. Within a community, both cooperation and exploitation can occur. Cells
are connected to each other with extracelullar matrix that enables communication and
at the same time protects cells against external influences, the immune system and
antimicrobial agents. Cells in biofilms have slower metabolism and altered gene
expression, which contribute to the difficult removal of biofilm infections. The latter
represent a major problem in healthcare, so it is essential to understand the responses of
biofilms to antibiotic therapy. In our thesis, we formed Escherichia coli biofilms in
coiled bioreactor and tested how different loading times as well as different
concentrations of antibiotic ampicilin in SM buffer affect biofilms and planktonic cells.
During the rinsing of biofilms, the susceptibility to the antibiotic decreased. We showed
that a higher concentration of ampicilin has a greater effect on both biofilms and
planktonic cells. Longer loading time had an impact on the final concentration of cells,
as the cell densities were higher with longer loading period.
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