Efficacy of methanolic extract of green and black teas against extended-spectrum β-Lactamase-producing Pseudomonas aeruginosa

Pseudomonas aeruginosa is one of the major bacteria causing acute infections. β-lactamase production is the principal defense mechanism in gram-negative bacteria. the aim of our study was to evaluate the antibacterial activity of methanolic extracts of green and black teas on p. aeruginosa extended spectrum-β-lactamases (esbls) production. this research was carried out on burn wounds of 245 hospitalized patients in kerman,iran. p. aeruginosa esbls and mbl producing strains were detected by combination disk diffusion test (cddt) and epsilometer test (e-test) strips,respectively. minimum inhibitory concentration (mic) was measured for ceftazidime,meropenem,imipenem,aztreonam,cefotaxime and methanollic extracts of camellia sinensis (green tea). from 245 patients in the burn ward,120 cases were infected with p. aeruginosa. 41 isolates contained esbl while mbl was not detected. p. aeruginosa were resistant to cefotaxime,aztreonam,ceftazidime,meropenem and imipenem,72 (60%),50 (41.66%),79 (65.83%),33 (27.5%) and 24 (20%),respectively. green tea extract had the highest anti-bacterial effect on standard and p. aeruginosa strains in 1.25mg/ml concentration. this study determined that the methanolic extract of green tea has a higher effect against esbl producing p. aeruginosa than cefotaxime,aztreonam and ceftazidime.