Evaluation of the antimicrobial property of green tea extract and its synergistic effect on antimicrobials showing resistance in clinical isolates of a tertiary care hospital

Background: Antimicrobial resistance is a global health challenge with the increasing drug-resistant organisms even in community. Hence, there is a need for search of other alternatives to the antimicrobials which can replace or boost the activity of existing antimicrobials. Camellia sinensis (C. sinensis) is one of the most popular beverages worldwide and has been reported to demonstrate the antimicrobial activity against various pathogenic bacteria. Aim: The aim is to evaluate the antimicrobial property of green tea extract and its synergistic effect on antimicrobials showing resistance in clinical isolates. Materials and Methods: This cross-sectional, prospective, analytical study was conducted after due approval from the Institutional Ethics Committee. Green tea was procured and shade dried, and extraction was done by percolation and infusion method. The antimicrobial activities of these extracts were studied against standard strains and then on nonrepetitive clinical isolates from bacteriology laboratory showing resistance to the primary line of antimicrobials. Results: Our study showed antimicrobial action of green tea extract by percolation method against standard strain of Pseudomonas aeruginosa but not against Escherichia coli or Staphylococcus aureus. Minimum inhibitory concentration and minimum bactericidal concentration of green tea were found to be 12.5 μg/ml against standard strain of P. aeruginosa. The green tea extract exhibited synergistic activity against 21/30 clinical strains of nonfermenters tested from various clinical samples. No antibacterial action was found for extract prepared by infusion method against the standard American Type Culture Collection strains. Conclusion: C. sinensis could be explored as one of the alternatives or for synergistic action in combination with other antimicrobials for nonfermenters. Further investigation for potential toxicity and pharmacodynamic profile of the polyphenols is required