title: Synergistic interactions of epigallocatechin gallate and oxytetracycline against various drug resistant Staphylococcus aureus strains in vitro.
abstract: Epigallocatechin gallate (EGCG), the major catechin contained in tea leaves, is known to possess the synergistic anti-staphylococcal activity in combination with various β-lactam antibiotics and tetracycline. In the present study, we explored the in vitro combinatory effect of EGCG in combination with oxytetracycline against eight standard strains and clinical isolates of Staphylococcus aureus, including erythromycin, methicillin and tetracycline resistant strains. The minimum inhibitory concentrations were determined by the broth microdilution assay and the data were evaluated according to the sum of fractional inhibitory concentrations (∑FIC). Our results showed synergistic and additive interactions against all S. aureus strains tested (∑FIC 0.288-0.631), two of which were multidrug resistant. According to our best knowledge, it is the first report on the EGCG synergy with oxytetracycline. Considering its significant synergistic antimicrobial effect and low toxicity, we suggest EGCG as a promising compound for the development of new anti-staphylococcal formulations.
authors.affiliation: Department of Quality of Agricultural Products, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamycka 129, Prague 6, Suchdol, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Novy
authors.forename: Johana
authors.initials: J
authors.lastname: Rondevaldova
authors.forename: Lenka
authors.initials: L
authors.lastname: Kourimska
authors.forename: Ladislav
authors.initials: L
authors.lastname: Kokoska
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D004357:Drug Synergism; D004917:Erythromycin / Q000494:pharmacology; D016106:Methicillin Resistance; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D010118:Oxytetracycline / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D013662:Tea / Q000737:chemistry; D013752:Tetracycline / Q000494:pharmacology; D013753:Tetracycline Resistance
chemical_list: D000900:Anti-Bacterial Agents; D013662:Tea; D004917:Erythromycin; D002392:Catechin; C045651:epigallocatechin gallate; D013752:Tetracycline; D010118:Oxytetracycline