Background: Antibiotic resistance in Escherichia coli is a major concern for public health, as it reduces options to treat infections such at urinary tract infection (UTI). Green tea (Camellia sinensis) and other natural plant products have been of interest for their ability to modify antibiotic susceptibility of bacteria, a capacity largely attributed to bioactive polyphenols. Objective: The purpose of this work was to investigate in vitro the potential effect of green tea leaf ethanol extract on the antibiotic susceptibility of E. coli isolates. Materials and Methods: Green tea leaves was extracted using ethanol and re-dissolved 1% DMSO. Five concentrations of green tea leaves ethanol extract 0.60, 0.50, 0.30, 0.16 and 0.08 g/mL were studied. E. coli isolates were detected by biochemical procedures and further tested using a VITEK 2 compact analyzer according to their biological profile; susceptibility to different antibiotic types was also established. Results: Exposure to green tea leaf ethanol extract at 0.16g/ml and 0.08 g/mL concentrations was associated with notable changes in the antibiotic susceptibility profile of E. coli. The observed alterations included a shift from a generally susceptible profile to an extensively drug-resistant (XDR) phenotype under the experimental conditions. Conclusion: Findings suggest that green tea leaf ethanol extract may modulate E. coli antibiotic resistance profile in vitro, indicating potential relationship between plant compounds and microbial antibacterial resistance mechanisms necessitating additional exploration
