Antimicrobial and Antibiofilm Activities of Essential Oils againstO157:H7 and Methicillin-Resistant(MRSA).
Antibiotics (Basel). 2020 Oct 24 ;9(11). Epub 2020 Oct 24. PMID: 33114324
The emergence of multidrug resistant microorganisms represents a global challenge due to the lack of new effective antimicrobial agents. In this sense, essential oils (EOs) are an alternative to be considered because of their anti-inflammatory, antiviral, antibacterial, and antibiofilm biological activities. Therefore, multiple efforts have been made to consider the potential use of EOs in the treatment of infections which are caused by resistant microorganisms. In this study, 15 EOs of both Colombian and introduced aromatic plants were evaluated against pathogenic strains ofO157:H7 and methicillin resistant(MRSA) in planktonic and sessile states in order to identify relevant and promising alternatives for the treatment of microbial infections. Forty different compounds were identified in the 15 EO with nine of them constituted mainly by oxygenated monoterpenes (OM). EOs from, chemotypes thymol, and carvacrol, displayed the highest antibacterial activity againstO157:H7 (MIC= 0.9 and 0.3 mg/mL, respectively) and MRSA (MIC= 1.2 and 0.6 mg/mL, respectively). These compounds from EOs had also the highest antibiofilm activity (inhibition percentage>70.3%). Using scanning electron microscopy (SEM), changes in the size and morphology of both bacteria were observed when they were exposed to sub-inhibitory concentrations ofEO carvacrol chemotype. EOs from, thymol, and carvacrol chemotypes represented a viable alternative for the treatment of microbial infections; however, the Selectivity Index (SI≤ 3) indicated that it was necessary to study alternatives to reduce its in vitro cytotoxicity.