High Potency of Essential Oil against Multi-Drug Resistant Gram-Negative Bacteria and Methicillin-Resistant .
Alessandra Oliva, Silvia Costantini, Massimiliano De Angelis, Stefania Garzoli, Mijat Božović, Maria Teresa Mascellino, Vincenzo Vullo, Rino Ragno
Author Information
Alessandra Oliva: Department of Public Health and Infectious Diseases, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy. alessandra.oliva@uniroma1.it.
Silvia Costantini: Department of Public Health and Infectious Diseases, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy. silviacostantini89@gmail.com.
Massimiliano De Angelis: Department of Public Health and Infectious Diseases, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy. massimiliano.deangelis@uniroma1.it.
Stefania Garzoli: Rome Center for Molecular Design, Department of Drug Chemistry and Technology, Sapienza University, P.le Aldo Moro 5, 00185 Rome, Italy. stefania.garzoli@uniroma1.it. ORCID
Mijat Božović: Faculty of Natural Sciences and Mathematics, University of Montenegro, Džordža Vašingtona bb, 81000 Podgorica, Montenegro. mijatboz@gmail.com. ORCID
Maria Teresa Mascellino: Department of Public Health and Infectious Diseases, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy. mariateresa.mascellino@uniroma1.it.
Vincenzo Vullo: Department of Public Health and Infectious Diseases, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy. vincenzo.vullo@uniroma1.it.
Rino Ragno: Rome Center for Molecular Design, Department of Drug Chemistry and Technology, Sapienza University, P.le Aldo Moro 5, 00185 Rome, Italy. rino.ragno@uniroma1.it. ORCID
PURPOSE: Herein, an extended investigation of Tea tree oil (TTO) against a number of multi-drug resistant (MDR) microorganisms in liquid and vapor phases is reported. METHODS: The activity of TTO was tested against methicillin-sensitive (MSSA), , and clinical strains of methicillin-resistant (MRSA), extended-spectrum beta lactamases producer carbapenem-sensitive (ESBL-CS-Kp), carbapenem-resistant (CR-Kp), (CR-Ab), and (CR-Pa). Minimal inhibitory/bactericidal concentrations (MIC/MBCs) and synergistic activity between TTO and different antimicrobials were determined. In the vapor assay (VP), TTO-impregnated discs were placed on the lid of a petri dish and incubated for 24 h at 37 °C. RESULTS: TTO showed a potent bactericidal activity against all the tested microorganisms. TTO in combination with each reference antimicrobial showed a high level of synergism at sub-inhibitory concentrations, particularly with oxacillin (OXA) against MRSA. The VP assay showed high activity of TTO against CR-Ab. CONCLUSION: Evaluation of in-vitro activity clearly indicated TTO as a potential effective antimicrobial treatment either alone or in association with known drugs against MDR. Therefore, TTO could represent the basis for a possible role in non-conventional regimens against and Gram-negative MDR. TTO in VP might represent a promising option for local therapy of pneumonia caused by CR-Ab.
