title: Synergistic antimicrobial activity of Camellia sinensis and Juglans regia against multidrug-resistant bacteria.
abstract: Synergistic combinations of antimicrobial agents with different mechanisms of action have been introduced as more successful strategies to combat infections involving multidrug resistant (MDR) bacteria. In this study, we investigated synergistic antimicrobial activity of Camellia sinensis and Juglans regia which are commonly used plants with different antimicrobial agents. Antimicrobial susceptibility of 350 Gram-positive and Gram-negative strains belonging to 10 different bacterial species, was tested against Camellia sinensis and Juglans regia extracts. Minimum inhibitory concentrations (MICs) were determined by agar dilution and microbroth dilution assays. Plant extracts were tested for synergistic antimicrobial activity with different antimicrobial agents by checkerboard titration, Etest/agar incorporation assays, and time kill kinetics. Extract treated and untreated bacteria were subjected to transmission electron microscopy to see the effect on bacterial cell morphology. Camellia sinensis extract showed higher antibacterial activity against MDR S. Typhi, alone and in combination with nalidixic acid, than to susceptible isolates." We further explore anti-staphylococcal activity of Juglans regia that lead to the changes in bacterial cell morphology indicating the cell wall of Gram-positive bacteria as possible target of action. The synergistic combination of Juglans regia and oxacillin reverted oxacillin resistance of methicillin resistant Staphylococcus aureus (MRSA) strains in vitro. This study provides novel information about antimicrobial and synergistic activity of Camellia sinensis and Juglans regia against MDR pathogens.
authors.affiliation: Immunology and Infectious Diseases Research Laboratory, Department of Microbiology, University of Karachi, Karachi, Pakistan; Department of Biomedical Sciences, University of Sassari, Sassari, Italy; Division of Immunology, International Institute of Infection and Immunity, Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Amber
authors.initials: A
authors.lastname: Farooqui
authors.affiliation: Immunology and Infectious Diseases Research Laboratory, Department of Microbiology, University of Karachi, Karachi, Pakistan; Department of Biomedical Sciences, University of Sassari, Sassari, Italy.
authors.forename: Adnan
authors.initials: A
authors.lastname: Khan
authors.affiliation: Department of Biomedical Sciences, University of Sassari, Sassari, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Borghetto
authors.affiliation: Immunology and Infectious Diseases Research Laboratory, Department of Microbiology, University of Karachi, Karachi, Pakistan.
authors.forename: Shahana U
authors.initials: SU
authors.lastname: Kazmi
authors.affiliation: Department of Biomedical Sciences, University of Sassari, Sassari, Italy; Department of Infection and Immunity, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Rubino
authors.affiliation: Department of Biomedical Sciences, University of Sassari, Sassari, Italy.
authors.forename: Bianca
authors.initials: B
authors.lastname: Paglietti
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D028241:Camellia sinensis / Q000737:chemistry*; D004357:Drug Synergism; D031324:Juglans / Q000737:chemistry*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D009268:Nalidixic Acid / Q000494:pharmacology; D010068:Oxacillin / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D009268:Nalidixic Acid; D010068:Oxacillin