Abstract Title:

Antibacterial activity of epigallocatechin-3-gallate (EGCG) and its synergism withβ-lactam antibiotics sensitizing carbapenem-associated multidrug resistant clinical isolates of Acinetobacter baumannii.

Abstract Source:

Phytomedicine. 2017 Jan 15 ;24:49-55. Epub 2016 Nov 17. PMID: 28160861

Abstract Author(s):

Spencer Lee, Ghaida Saleh Al Razqan, Dong H Kwon

Article Affiliation:

Spencer Lee


BACKGROUND: Infections caused by Acinetobacter baumannii were responsive to conventional antibiotic therapy. However, recently, carbapenem-associated multidrug resistant isolates have been reported worldwide and present a major therapeutic challenge. Epigallocatechin-3-Gallate (EGCG) extracted from green tea exhibits antibacterial activity.

PURPOSE: We evaluated the antibacterial activity of EGCG and possible synergism with antibiotics in carbapenem-associated multidrug resistant A. baumannii. A potential mechanism for synergism was also explored.

MATERIALS AND METHODS: Seventy clinical isolates of A. baumannii collected from geographically different areas were analyzed by minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of EGCG. Checkerboard and time-killing assays were performed to exam the synergism between EGCG and antibiotics. The effects of EGCG on a multidrug efflux pump inhibitor (1-[1-naphthylmethyl] piperazine; NMP) andβ-lactamase production were also examined in A. baumannii.

RESULTS: Sixty-three of 70 clinical isolates of A. baumannii carried carbapenemase-encoding genes with carbapenem-associated multidrug resistance. Levels of MIC and MBC of EGCG ranged from 64 to 512µg/ml and from 128 to ≥1024µg/ml, respectively among the clinical isolates. MIC90 and MBC86 levels were 256µg/ml and 512µg/ml of EGCG, respectively. Subinhibitory concentration of EGCG in combination with all antibiotics tested, including carbapenem, sensitized (MICs fall≤1.0µg/ml) all carbapenem-associated multidrug resistant isolates. Checkerboard and time-killing assays showed synergism between EGCG and meropenem (or carbenicillin) counted as fractional inhibitory concentration of< 0.5 and cell numbers' decrease per ml of>2log10 within 12h, respectively. EGCG significantly increased the effect of NMP but was unrelated toβ-lactamase production in A. baumannii, suggesting EGCG may be associated with inhibition of efflux pumps.

CONCLUSION: Overall we suggest that EGCG-antibiotic combinations might provide an alternative approach to treat infections with A. baumannii regardless of antibiotic resistance.

Print Options

Sayer Ji
Founder of GreenMedInfo.com

Subscribe to our informative Newsletter & get Nature's Evidence-Based Pharmacy

Our newsletter serves 500,000 with essential news, research & healthy tips, daily.

Download Now

500+ pages of Natural Medicine Alternatives and Information.

This website is for information purposes only. By providing the information contained herein we are not diagnosing, treating, curing, mitigating, or preventing any type of disease or medical condition. Before beginning any type of natural, integrative or conventional treatment regimen, it is advisable to seek the advice of a licensed healthcare professional.

© Copyright 2008-2021 GreenMedInfo.com, Journal Articles copyright of original owners, MeSH copyright NLM.