Antibacterial effect of Methanolic extract of Camellia Sinensis L. on Pseudomonas aeruginosa strains producing β-lactamases

Pseudomonas aeruginosa is one of the important causes of nosocomial infections. Extended spectrum-beta Lactamases (ESBLs) and Metallo-beta Lactamase (MBL) producing strains have become resistant against a wide range of antibiotics. The aim of this study was to determine the effect of Methanol extract of Camellia Sinensis on Pseudomonas aeruginosa producing ESBL isolated from burnt wounds of patients. This descriptive study was done on burnt wounds of 245 hospitalaized patients in Shafa hospital, Kerman, Iran during 2006-07. ESBLs producing strains were detected by phenotypic confirmatory test and also E-test strips were used for MBL detection. P.aeruginosa MIC was determined for Cefotaxime, Ceftazidime, Azteronam, Imipenem, Meropenem and methanol extracts of plant Camellia Sinensis prepared by Maceration method. 120 of burnt wound infected with P.aeruginosa, out of them 41 isolates contained ESBL while lacked MBL. 60% of isolates were resistant to Cefotaxime, 66% to Ceftazidime, 42% to Azteronam, 3% to Imipenem and 5% to Meropenem. Among the extracts, green Tea had the highest antibacterial effect on standard strains and P.aeruginosa producing ESBLs in 1.25mg/ml concentration. This study showed that methanolic extract of green tea has higher antibacterial effect aginst β-lactamase P.aeruginosa strains than Cefotaxime and Ceftazidime.