Inhibition of Staphylococcus aureus cocktail using the synergies of oregano and rosemary essential oils or carvacrol and 1,8-cineole

• Main Authors: Vanessa Gonçalves Honório, Jéssica Bezerra Rodrigues, Geany Targino Souza, Rayssa Julliane Carvalho, Nelson Justino Gomes-Neto, Regina Celia Bressan de Queiroz Figueiredo, Janaína V Melo, Evandro Leite Souza, Marciane eMagnani
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2015-11-01
• Series: Frontiers in Microbiology
• Subjects: S. aureus; Antimicrobial activity; Essential oil; Oregano; Rosemary; Food matrices
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fmicb.2015.01223/full

This study assessed the inhibitory effects of the essential oils (EOs) from Origanum vulgare L. (OVEO) and Rosmarinus officinalis L. (ROEO), as well as of the its majority individual constituents (ICs) carvacrol (CAR) and 1,8-cineole (CIN), respectively, combined at subinhibitory concentrations against a cocktail of Staphylococcus aureus. The Minimum inhibitory Concentration (MIC) of OVEO and CAR against S. aureus cocktail was 1.25 µL/mL, while the MIC of ROEO and CIN was 10 µL/mL. The Fractional Inhibitory Concentration Index of the combined EOs or ICs was ≤ 0.5 indicating a synergic interaction. The incorporation of OVEO and ROEO or CAR and CIN at different combinations in cheese and meat broths caused a decrease (p ≤ 0.05) of initial counts of S. aureus. Combined application of 1/8 MIC OVEO and 1/4 MIC ROEO or 1/4 MIC CAR and 1/4 MIC CIN in meat and cheese samples reduced (p ≤ 0.05) the viable cells counts and caused morphological changes in S. aureus cells, such as cell shrinkage and appearance of blebbing-like structures on cell surfaces. However, in cheese and meat samples the decrease in viable cell counts was smaller (p ≤ 0.05) than that observed in cheese and meat broths. These findings reinforce the potential of the use of OVEO and ROEO or CAR and CIN in combination to control S. aureus in cheese and meat matrices.