The increasing problem of bacterial resistance to antibiotics requires innovative approaches to improve their effectiveness. The use of electroporation, a method to increase the permeability of the cell membrane, is one such approach to improve the effect of antibiotics on bacteria. In our master's thesis, we investigated the effects of combining electroporation and antibiotics on the growth of the Gram-positive bacterium Lactiplantibacillus plantarum, focusing on comparing the effects of three different antibiotics with different mechanisms of action. We incubated the bacteria with antibiotics, with electroporation at different electric field amplitude (0, 5, 10, 15 and 20 kV/cm), for one hour and 24 hours after electroporation to determine the effects of incubation time on the efficacy of electroporation and antibiotic action. Bacteria were electroporated in a 250 mM sucrose solution containing an antibiotic (ampicillin, tetracycline, or ciprofloxacin) at four concentrations: the minimum inhibitory concentration (MIC) and its threefold, tenfold and thirtyfold values. The efficacy of electroporation and antibiotics in inhibiting bacterial growth was analyzed by incubating the electroporated samples on Petri dishes with MRS growth medium and 24-hour spectrophotometrically monitoring their growth using a microplate reader. Due to the high electric conductivity of the samples with higher concentrations of ciprofloxacin, this antibiotic was excluded from further testing. The results showed that electroporation increases the effectiveness of antibiotics and reduces bacterial growth by more than one logarithmic unit, with higher electroporation intensity and higher antibiotic concentrations leading to greater growth inhibition. When analyzing the effect of combining electroporation with an antibiotic, we found that ampicillin was more effective at lower concentrations, while tetracycline showed greater growth inhibition at higher concentrations. Electroporation eases the transport of anticotics through the cell wall. Since the targets for ampicillin are located beneath the cell wall, a higher level of inhibition is visible even at low concentrations. Compared to ampicillin, the tetracycline targets are located inside the cell, making tetracycline more effective at higher concentrations.
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