Susceptibility of methicillin-resistant staphylococci to oregano essential oil, carvacrol and thymol

Authors

  • Antonia Nostro,

    Corresponding author
    1. Dipartimento Farmaco-Biologico, Sezione Microbiologia, Facoltà di Farmacia, Università di Messina, Villaggio Annunziata, 98168 Messina, Italy
      *Corresponding author. Tel.: +39 (090) 3533120, 6766443; Fax: +39 (090) 6766438, E-mail address: atnostro@pharma.unime.it
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  • Anna R Blanco,

    1. Dipartimento R&D, SIFI S.p.A., Via Ercole Patti 36, Lavinaio, 95020 Catania, Italy
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  • Maria A Cannatelli,

    1. Dipartimento Farmaco-Biologico, Sezione Microbiologia, Facoltà di Farmacia, Università di Messina, Villaggio Annunziata, 98168 Messina, Italy
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  • Vincenzo Enea,

    1. Dipartimento R&D, SIFI S.p.A., Via Ercole Patti 36, Lavinaio, 95020 Catania, Italy
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  • Guido Flamini,

    1. Dipartimento di Chimica Bioorganica e Biofarmacia, Facoltà di Farmacia, Università di Pisa, Via Bonanno 33, 56126 Pisa, Italy
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  • Ivano Morelli,

    1. Dipartimento di Chimica Bioorganica e Biofarmacia, Facoltà di Farmacia, Università di Pisa, Via Bonanno 33, 56126 Pisa, Italy
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  • Andrea Sudano Roccaro,

    1. Dipartimento R&D, SIFI S.p.A., Via Ercole Patti 36, Lavinaio, 95020 Catania, Italy
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  • Vittorio Alonzo

    1. Dipartimento Farmaco-Biologico, Sezione Microbiologia, Facoltà di Farmacia, Università di Messina, Villaggio Annunziata, 98168 Messina, Italy
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*Corresponding author. Tel.: +39 (090) 3533120, 6766443; Fax: +39 (090) 6766438, E-mail address: atnostro@pharma.unime.it

Abstract

The aim of this study was to evaluate the susceptibility of methicillin-susceptible and methicillin-resistant staphylococci (MSS, MRS) to oregano essential oil, carvacrol and thymol. The commercial aerial parts of Origanum vulgare L. were hydrodistilled and the essential oil analysed by gas- chromatography/electron impact mass spectrometry. The inhibition efficacy of this essence and its major components was assayed against 26 MSS and 21 MRS, using an agar dilution method. The methicillin resistance was thoroughly typed by Epsilometer test (E-test), polymerase chain reaction for mecA gene detection and PBP2′ latex agglutination test. The results clearly demonstrated that the comparison between the susceptibility of MSS and MRS to oregano oil, carvacrol and thymol showed no significant differences (Fisher's exact test, P>0.05). The best minimum inhibitory concentration values were reported for carvacrol (0.015–0.03%, v/v) followed by thymol (0.03–0.06%, v/v) and oregano oil (0.06–0.125%, v/v).

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