Antimicrobial Activity of the Green Tea Polyphenol (−)-Epigallocatechin-3-Gallate (EGCG) against Clinical Isolates of Multidrug-Resistant <i>Vibrio cholerae</i>

• Main Authors: Achiraya Siriphap (Author), Anong Kiddee (Author), Acharaporn Duangjai (Author), Atchariya Yosboonruang (Author), Grissana Pook-In (Author), Surasak Saokaew (Author), Orasa Sutheinkul (Author), Anchalee Rawangkan (Author)
• Format: Book
• Published: MDPI AG, 2022-04-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 10.3390/antibiotics11040518; 2079-6382
• Keywords: antimicrobial activity; EGCG; green tea; MDR; <i>Vibrio cholerae</i>; Therapeutics. Pharmacology; RM1-950
• Source: Antibiotics, Vol 11, Iss 4, p 518 (2022)

The spread of multidrug-resistant (MDR) <i>Vibrio cholerae</i> necessitates the development of novel prevention and treatment strategies. This study aims to evaluate the in vitro antibacterial activity of green tea polyphenol (−)-epigallocatechin-3-gallate (EGCG) against MDR <i>V. cholerae</i>. First, MIC and MBC values were evaluated by broth microdilution techniques against 45 <i>V. cholerae</i> strains. The checkerboard assay was then used to determine the synergistic effect of EGCG and tetracycline. The pharmaceutical mode of action of EGCG was clarified by time-killing kinetics and membrane disruption assay. Our results revealed that all of the 45 clinical isolates were susceptible to EGCG, with MIC and MBC values in the range of 62.5-250 µg/mL and 125-500 µg/mL, respectively. Furthermore, the combination of EGCG and tetracycline was greater than either treatment alone, with a fractional inhibitory concentration index (FICI) of 0.009 and 0.018 in the O1 and O139 representative serotypes, respectively. Time-killing kinetics analysis suggested that EGCG had bactericidal activity for MDR <i>V. cholerae</i> after exposure to at least 62.5 µg/mL EGCG within 1 h. The mode of action of EGCG might be associated with membrane disrupting permeability, as confirmed by scanning electron microscopy. This is the first indication that EGCG is a viable anti-MDR <i>V. cholerae</i> treatment.