Antibacterial, Antibiofilm and Anti-adhesion Activities of Piper Betle Leaf Extract Against Avian Pathogenic Escherichia Coli

Abstract Piper betle leaves have traditionally been used to treat many diseases, including bacterial infections. The present study aimed to investigate the antibacterial, antibiofilm, and anti-adhesion activities of P. betle extract against Avian pathogenic Escherichia coli (APEC). The ethanol extract of P. betle leaves demonstrated strong antibacterial activity against clinical isolates of APEC with MIC and MBC values ranging from 0.5-1.0 mg/mL. Disruption and breakdown of the bacterial cells were detected when the cells were challenged with the extract at 2×MIC. Bacterial cells treated with the extract demonstrated longer cells without a septum, compared to the control. The extract at 1/8, 1/4, and 1/2×MIC significantly inhibited the formation of bacterial biofilm of the isolates (P<0.05) without inhibiting growth. At 1/2×MIC, 55% of the biofilm inhibition was detected in APEC CH09, a strong biofilm producer. At 32×MIC, 88% of the inhibition of viable cells embedded in the mature biofilm was detected in APEC CH09. Reduction in the bacterial adhesion to surfaces was shown when APEC were treated with sub-MICs of the extract as observed by SEM. The results suggested potential medicinal benefits of P. betle extract for the treatment of the infection caused by Avian pathogenic E. coli.