Synergistic antibacterial effect of ciprofloxacin and green tea extract on methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from clinical cases

Abstract

Objective: The aim of this study was to investigate the synergistic effect of ciprofloxacin and green tea extract combinations against methicillin resistant Staphylococcus aureus (MRSA) strains isolated from various clinical registries. Methods: Presumptive 90 MRSA strains isolated from various clinical specimens were identified by the biochemical tests followed by an automated bacterial recognition system. Resistance of isolates to ciprofloxacin was determined using a disk diffusion test. Minimum inhibitory concentration (MIC) values of green tea extract and ciprofloxacin were determined for 54 MRSA isolates resistant to ciprofloxacin by microdilution method. Subsequently, the synergistic effect of the green tea + ciprofloxacin combinations against the isolates were determined by the checkboard dilution method to calculate fractional inhibitory concentration values. Results: MRSA strains were isolated from three clinical sample types including wounds (54.4%), blood (30%) and urine (15.6%). MIC values of green tea extract, ciprofloxacin and their tested combinations ranged between 8 and 256 µg/ml. The synergetic effect of green tea extract on ciprofloxacin for 54 MRSA isolates were determined as ineffective for 18 (33.3%), aditive for 17 (31.5%), and synergic for 19 (35.2%) strains based on fractional inhibitory concentration values. Conclusion: The results of this study showed that green tea extract and ciprofloxacin had a synergetic antibacterial effect on MRSA strains isolated from various clinical specimens. © 2022. All Rights Reserved.