Antipathogenic properties of green tea polyphenol epigallocatechin gallate at concentrations below the MIC against enterohemorrhagic Escherichia coli O157:H7.
The inhibitory effects of green tea polyphenol epigallocatechin gallate (EGCG) on virulence phenotypes and gene expression regulated by quorum sensing (QS) in Escherichia coli O157:H7 were demonstrated at concentrations of 1 to 100 microg/ml, which are lower than the MIC (539 +/- 22 microg/ml). At 25 microg/ml, the growth rate was not affected, but autoinducer 2 concentration, biofilm formation, and swarm motility decreased to 13.2, 11.8, and 50%, respectively. Survival at 5 days of nematodes (Caenorhabditis elegans) that were fed the pathogen without and with EGCG were 47.1 and 76%, respectively. Real-time PCR data indicated decreased transcriptional level in many quorum sensing-regulated virulence genes at 25 microg/ml. Our results suggest that EGCG at concentrations below itsMIC has significant antipathogenic effects against E. coli O157:H7.
Department Chemistry and Nano Sciences (BK21), Ewha Womans University, Seoul 120-750, Korea.
Kang-Mu
KM
Lee
Wan-Seok
WS
Kim
Jeesun
J
Lim
Sunyoung
S
Nam
Min
M
Youn
Seong-Won
SW
Nam
Younghoon
Y
Kim
Sae-Hun
SH
Kim
Woojun
W
Park
Sungsu
S
Park
D000818:Animals; D018441:Biofilms / Q000254:growth & development; D017173:Caenorhabditis elegans / Q000254:growth & development / Q000382:microbiology*; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity*; D029968:Escherichia coli Proteins / Q000032:analysis; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D008826:Microbial Sensitivity Tests; D053038:Quorum Sensing; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013662:Tea / Q000737:chemistry*; D014774:Virulence / Q000235:genetics
D029968:Escherichia coli Proteins; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate