Comparative Antibacterial Effectiveness of Orange Peel Extracts from Five Varieties Against Strain of Multi Drug Resistance Escherichia coli

The purpose of this study was to investigate the antibacterial activity of orange peel extracts from five different orange varieties in North Sumatera against resistant Escherichia coli bacteria and compare it to the effectiveness of vancomycin and erythromycin. To assess antibacterial activity, orange peel extracts were prepared from five different orange varieties, namely Citrus aurantifolia, Citrus microcarpa Bunge, Citrus limon L., Citrus sinensis L., and Citrus hystrix. Antibacterial activities were evaluated using the microdilution method to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The best antibacterial activity was determined using the smallest MIC and MBC values. The research found that all five orange peel extracts exhibited significant antibacterial activity compared to the standard antibiotics vancomycin and erythromycin. The most potent inhibitory effect was observed with the Citrus hystrix peel extract, with the lowest MIC and MBC (125 and 250 µg/mL), followed by Citrus aurantifolia (250 and 500 µg/mL), and Citrus sinensis L. (500 and 500 µg/mL). The results showed significant antibacterial activity of orange peel extracts from five different orange varieties in North Sumatera against resistant Escherichia coli bacteria. Keywords: Antibiotic resistance, citrus peel extracts, Escherichia coli, MIC, MBC.