Inhibition of Biofilm Formation by the Synergistic Action of EGCG-S and Antibiotics.

Shrameeta Shinde,Lee H Lee,Tinchun Chu

doi:10.3390/antibiotics10020102

Shrameeta Shinde, Lee H Lee + Show 1 more

Open Access

https://doi.org/10.3390/antibiotics10020102

Copy DOI

Abstract

Biofilm, a stress-induced physiological state, is an established means of antimicrobial tolerance. A perpetual increase in multidrug resistant (MDR) infections associated with high mortality and morbidity have been observed in healthcare settings. Multiple studies have indicated that the use of natural products can prevent bacterial growth. Recent studies in the field have identified that epigallocatechin gallate (EGCG), a green tea polyphenol, could disrupt bacterial biofilms. A modified lipid-soluble EGCG, epigallocatechin-3-gallate-stearate (EGCG-S), has enhanced the beneficial properties of green tea. This study focuses on utilizing EGCG-S as a novel synergistic agent with antibiotics to prevent or control biofilm. Different formulations of EGCG-S and selected antibiotics were used to study their combinatorial effects on biofilms produced by five potential pathogenic bacteria, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, and Mycobacterium smegmatis. The crystal violet (CV) assay and the sensitive fluorescence-based resazurin biofilm viability assay were used to assess the biofilm production. Our results identified optimal formulation for each bacterium, effectively inhibiting biofilm formation to an extent of 95–99%. Colony-forming unit (CFU) and cell viability analyses showed a decrease of viable bacteria. These results depict the potential of EGCG-S as a synergistic agent with antibiotics and as an anti-biofilm agent.

Highlights

Selective environmental pressures force bacteria to adapt by altering their growth state
The inhibitory effect of erythromycin (E) and epigallocatechin gallate (EGCG)-S (ES) treatments, individually and/or in combination, on E. coli biofilm formation was evaluated by Colony-forming unit (CFU) analysis
This study successfully demonstrated the synergistic inhibitory effects of a modified green tea polyphenol, EGCG-S, in combination with antibiotics on biofilm formation in five distinct potential pathogenic bacteria

Summary

Introduction

Selective environmental pressures force bacteria to adapt by altering their growth state. One preferred state is biofilm, which exists in almost 90% of bacteria. Biofilm is a three-dimensional, multicellular surface-tethered bacterial aggregation embedded in an extracellular matrix (ECM). During biofilm formation, planktonic cells attach to surface and transition to the sessile state to secrete an extracellular polymeric substance (EPS) forming a protective barrier against abiotic and biotic stressors. The cells are shed for dispersal which transition into planktonic cells [1]. Relevant biofilm-associated infections are either tissue or device-related infections. Chronic tissue infections include wounds, dental plaque, urinary tract infection, cystic fibrosis, and so on, while medical devices like catheters, prosthetic heart valves, orthopedic implants, and so on are colonized by bacteria [3]

Methods

Results

Conclusion