Selected Essential Oils as Antifungal Agents Against Antibiotic-ResistantCandidaspp.:In VitroStudy on Clinical and Food-Borne Isolates

Abstract

Candida spp. cause significant health problems, inducing various types of superficial and deep-seated mycoses in humans. As a result of the increasing antibiotic resistance among pathogenic yeasts, the interest in alternative agents of antifungal activity is growing. This study evaluated the antimicrobial activity of selected essential oils (EOs) against Candida clinical and food-borne strains, including antibiotic-resistant isolates, in relation to yeast cell surface hydrophobicity (CSH). Candida strains showed different range of susceptibility to tea tree, thyme, peppermint, and clove oils, and peppermint oil demonstrated the lowest anticandidal activity with minimal inhibitory concentrations (MICs) of 0.03-8.0% v/v. MIC values for thyme and clove oils ranged from 0.03% to 0.25% v/v, and for tea tree oil-from 0.12% to 2.0% v/v. The exception was Candida tropicalis food-borne strain, the growth of which was inhibited after application of EOs at concentration of 8% v/v. Due to diverse yeast susceptibility to EOs, isolates were divided into five clusters in a principal component analysis model, each containing both clinical and food-borne strains. Hydrophobic properties of yeast were also diversified, and 37% of clinical and 50% of food-borne strains exhibited high hydrophobicity. The study indicates high homology of clinical and food-borne Candida isolates in relation to their susceptibility to anticandidal agents and hydrophobic properties. The susceptibility of yeasts to EOs could be partially related to their CSH. High antifungal activity of examined EOs, also against antibiotic-resistant isolates, indicates their usefulness as agents preventing the development of Candida strains of different origin.

Candida albicans Impairments Induced by Peppermint and Clove Oils at Sub-Inhibitory Concentrations

“…The growth of C. albicans was observed on solid medium supplemented with peppermint and clove oils at concentrations ranging from 0.0075 to 0.25% v / v , corresponding to half or less of their minimum inhibitory concentrations (MIC of peppermint oil: 1.0% v / v , MIC of clove oil: 0.5% v / v , determined in our previous study) [14]. Irrespective of the type and concentration of the essential oil, morphological changes of the colonies were noted.…”

Biological effects of various chemically characterized essential oils: investigation of the mode of action against Candida albicans and HeLa cells

“…Essential oils were used at their minimal inhibitory concentration (MIC) values: 0.5% v/v for tea tree and clove oils, 0.25% v/v for thyme oil, and 1.0% v/v for peppermint oil, as previously determined. 13 To enhance the solubility of the essential oils, ethanol was included at a nal concentration of 0.5% v/v (this concentration of ethanol did not cause leakage from C. albicans cells, as determined by preliminary studies). Yeast cell suspensions were treated with essential oils for different periods of time, i.e., 0, 30, 60, 90, 120, 150 and 180 min.…”

“…Previously, we demonstrated a broad spectrum of changes in C. albicans morphology, metabolic activity and protein proles induced by thyme, tea tree, clove and peppermint oils. 12,13 The chemical complexity of the essential oils justies the hypothesis of their probable multidirectional action on eukaryotic cells. The biological activities of the oils were usually attributed to phenolic (e.g., eugenol, thymol, carvacrol, and chavicol) or terpene (e.g., menthol, a-terpineol, carveol, geranial, neral, and menthone) compounds.…”

Microbiological Safety and Antibiogram Analysis of Selected Food Products Obtained in the Marketplace of Peshawar and Mardan, KPK, Pakistan

“…These include Vancomycin, Azithromycin, Amoxicillin, Cefotaxime, methicillin, Ceftriaxone, Levofloxacin (for Gram-positive bacteria) and for gram -veCefixime, Cefuroxime, Lanzolid, Cefoxitin, Ciprofloxacin, Ceclor, and Chloramphenicol (for Gram positive bacteria) were assessed for their antibacterial activities against the bacterial isolates. For fungal pathogens the antifungals Fluconazol, Voriconazol, and nystatin were used [27].…”