Green tea as an effective antimicrobial for urinary tract infections caused by Escherichia coli

Abstract

Background: Urinary tract infections (UTIs) are a very most common type of infection worldwide, and result in billions of dollars in medical care costs. Escherichia coli is the infective agent for 80–90% of all UTIs. Green tea, derived from leaves of the Camellia sinensis plant has been shown to have various potential health benefits (e.g., cardiovascular disease and cancer). The major beneficial components of green tea have been characterized, and are now known to be polyphenolic catechins. The main catechins in green tea are (-)-epicatechin-3-gallate, (-)-epigallocatechin (EGC), (-)-epicatechin, and (-)-epigallocatechin-3-gallate (EGCG). EGCG and EGC have been shown to have the greatest antimicrobial effects, but only EGC has been shown to be excreted in urine. Isolates of E. coli from UTIs collected between 2007 and 2008 were characterized for antimicrobial resistance to standard drugs. Then 80 of these isolates, representing a wide spectrum of antimicrobial susceptibility patterns, were selected for testing using an extract of green tea.Results: The concentrations of green tea extract tested were 0, 2.5, 3.0, 3.5, and 4.0 mg/ml. All of the strains tested, except one, had minimum inhibitory concentrations (MICs) of ≤4.0 mg/ml (99%), with 94% of the isolates having an MIC of ≤3.5 mg/ml, 76% of the isolates having an MIC of ≤3.0 mg/ml, 40% of the isolates having an MIC of ≤2.5 mg/ml. Two control strains varied in susceptibility, one having an MIC of ≤2.5 mg/ml,and the other having an MIC of ≤3.5 mg/ml.Conclusion: Since EGC has been shown to have antimicrobial effects on E. coli, and EGC has been shown to be excreted in the urine in a high enough concentration to potentially be effective as an antimicrobial; these MIC results suggest that ingesting green tea could have potential antimicrobial effects on UTIs caused by E. coli.

Assessment of aquo-ethanolic extract of Camellia sinensis against Carbapenem Resistant Escherichia coli: In Vivo Trials in a Murine Model

“…3). Earlier studies have also affirmed similar findings as Camellia sinensis extract exhibited in vitro bactericidal activity against Escherichia coli at concentrations of nearly 3500 mg/mL [32]. Polyphenols of Camellia sinensis at a dose of 3.125 mg/Kg had been reported to cause reduction of Pseudomonas sp.…”

Antibacterial effect of green tea extract against multi drug resistant Escherichia coli isolated from urine sample of patients visiting tertiary care hospital of Eastern Nepal

“…The past two decades have also witnessed a significant increase in clinically important resistance in a variety of bacterial species as well as the emergence of significant pathogens of intrinsically resistant strains previously considered to be of low pathogenicity (Smith et al, 2002). These challenges have been receiving growing interest to find alternative antimicrobial agents from plant extracts that need to be developed and used to control multidrug-resistant bacteria (Cushnie and Lamb, 2005;Song and Seong, 2007;Reygaert and Jusufi, 2013). Camellia sinensis (green tea) is one of the most popular beverages in the world, and has been reported to have antimicrobial effects against various pathogenic bacteria (Taylor et al, 2005;Cushnie and Lamb, 2005;Lee et al, 2005).…”

Çay Bitkisinin (Camellia sinensis) Bileşimi ve Sağlık Etkileri

“…Bu fenolik bileşiklerden özellikle EGCG ve EGC'den zengin yeşil çayın antimikrobiyal, antifungal ve antiviral etkilere sahip olduğu gösterilmektedir [66,67]. Bununla ilgili yapılan bir çalışmada yeşil çayın özellikle Escherichia coli'ye karşı potansiyel antimikrobiyal etkisi olduğu belirlenmiştir [68]. Yeşil çay yaprak özlerinin, çevresel kaynaklardan izole edilen çeşitli bakterilere karşı antibakteriyel etkinliğini test etmek amacıyla yapılan bir çalışmada yeşil çayın antibakteriyel aktivitesi saptanmıştır [69].…”