Bacterial biofilm represents a community of bacterial cells attached to the surface of the substrate and surrounded by extracellular polymeric substances (EPS), where cells show completely different growth, metabolic activity and resistence than planktonic cells. This multilayered bacterial growth often causes problems in many areas related to food, water, pharmacy and medicine. Eradication of biofilm is extremely difficult, due to the lower metabolic activity of cells inside the biofilm and thus less susceptibility to antibiotics and other antimicrobial agents. Moreover, the biofilm itself acts as a physical barrier to access the bacteria. Due to the high resistance of biofilm bacteria, new methods aimed at aliminating them are needed, and bacteriophages could be an interesting alternative as they are natural killers of bacteria. In the experimental work we successfully formed E.coli biofilm in a continuous custom build system with mixed and tubular bioreactor. To asses the resulting biofilm after 2 h of formation, the tube was intensely washed. The results have shown that the cells are retained in the tubular bioreactor, consisting of adsorbed cells on the inner wall of the tube, that are viable, but dormant, and free planktonic cells dispersed from the biofilm and traveling along the tube. We have shown that bacteriophages are capable of adsorbing and infecting biofilm bacteria, but their propagation doesn't continue until the biofilm is exposed to more favorable environment.
|
