Antibacterial Effects of Green Tea Polyphenols on Clinical Isolates of Methicillin-Resistant Staphylococcus aureus

Abstract

The antibacterial effects of tea polyphenols (TPP) extracted from Korean green tea (Camellia sinensis) against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) were evaluated. Characterization of the minimal inhibitory concentration (MIC) of oxacillin for 30 S. aureus strains isolated from patients treated with oxacillin identified 13 strains with an oxacillin MIC C 4 lg/mL as methicillinresistant Staphylococcus aureus (MRSA) (range: 8 to 512 lg/ mL), while 17 strains were methicillin-susceptible Staphylococcus aureus (MSSA) (range: 0.25-0.5 lg/mL). The MICs of TPP ranged from 50 to 180 lg/mL for both the MSSA and the MRSA strains. The MICs of oxacillin for each of the 13 MRSA strains were reduced between 8-and 128-fold when these strains were coincubated with sub-MIC (B0.59 MIC) levels of TPP, demonstrating that the combination of TPP plus oxacillin was synergistic for all of the clinical MRSA isolates. Two-dimensional polyacrylamide gel electrophoresis identified 14 extracellular proteins of MRSA-13 down-regulated and 3 proteins up-regulated by exposure to TPP. These studies demonstrate that TPP can differentially stimulate the expression of various proteins in these bacteria and synergize the bactericidal activity of oxacillin for MRSA.

Antimicrobial activity of green tea extract against isolates of methicillin–resistant Staphylococcus aureus and multi–drug resistant Pseudomonas aeruginosa

“…Green tea was also reported to have a synergistic effect with β-lactam antibiotics against MRSA [24][25][26][27][28] , It was also reported that the main component of tea polyphenols, epigallocatechin gallate can reverse methicillin resistance of MRSA by inhibiting the synthesis of PBP2 [29] , Epigallocatechin gallate not only increases the activity of β-lactams but also increases the activity of non-β-lactam cell wall biosynthesis inhibitors [26] .…”

The effects of regular hot black tea consumption on nasal carriage of methicillin-resistant Staphylococcus aureus

“…There are some other studies concluding that tea extracts may have potent antibacterial effects in vivo and in vitro against a wide range of pathogenic bacteria, including antibiotic-resistant strains. [9][10][11]18,21] Black tea extract has been found to be more effective against gram-positive bacteria such as S. aureus Haemophilus aphrophilus, Bacillus cereus, e.g., then gram-negative bacteria. The reason for this is lipopolysaccharides in the outer membrane of gram negative bacteria prevent penetration.…”

“…[6][7][8] Black tea extracted with eight different solvents, includes polyphenol contents which exhibit antibacterial and antioxidant activity against several types of pathogenic bacteria, including Vibrio cholerae, Escherichia coli, Shigella, Salmonella, and S. aureus. [9][10][11] Both in vivo and in vitro studies have demonstrated that tea or tea-based extracts have antimicrobial properties when applied topically. [12,13] But it is not clear whether or not tea exhibits the same antimicrobial activity when consumed orally as beverage.…”

Cellular Responses of Salmonella typhimurium Exposed to Green Tea Polyphenols

“…The stress shock proteins were analyzed by SDS-PAGE (A), and western blot with anti-DnaK (B), and anti-GroEL (C) monoclonal antibodies, respectively. 에 의하여 세포에 독성이 있다는 것을 보여준 바 있다 (Park et al, 2001;Cho et al, 2002Cho et al, , 2007Cho et al, , 2008Chang et al, 2004 …”