title: Additive, indifferent and antagonistic effects in combinations of epigallocatechin gallate with 12 non-beta-lactam antibiotics against methicillin-resistant Staphylococcus aureus.
abstract: Additive, indifferent and antagonistic effects were observed in combinations of epigallocatechin gallate (EGCg, a main constituent of tea catechins) with12 non-beta-lactam antibiotics against methicillin-resistant Staphylococcus aureus (MRSA). The combinations of EGCg with the inhibitors of either protein or nucleic acid synthesis showed additive or indifferent effects. These antibiotics included tetracycline, minocycline, chloramphenicol, streptomycin, gentamicin, kanamycin, erythromycin, rifampicin and ofloxacin. In contrast, EGCg showed an antagonistic tendency against glycopeptide antibiotics (vancomycin, teicoplanin and polymyxin B). The common property of these antibiotics is the peptide backbone structure, suggesting a direct binding of EGCg with the antibiotics. The above results indicate that tea catechins may affect the activities of antibiotics both positively and negatively.
authors.affiliation: Department of Microbiology and Immunology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan. zqhu@med.showa-u.ac.jp
authors.forename: Zhi-Qing
authors.initials: ZQ
authors.lastname: Hu
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Zhao
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Yoda
authors.forename: Nozomi
authors.initials: N
authors.lastname: Asano
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Hara
authors.forename: Tadakatsu
authors.initials: T
authors.lastname: Shimamura
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004357:Drug Synergism; D004359:Drug Therapy, Combination / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D016106:Methicillin Resistance / Q000502:physiology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D002392:Catechin; C045651:epigallocatechin gallate