Aims:  The in vitro activity of some essential oils (EO) (thyme red, fennel, clove, pine, sage, lemon balm and lavender) against clinical and environmental fungal strains was determined. Methods and Results:  The minimal inhibitory concentrations were determined by a microdilution method in RPMI 1640 and by a vapour contact assay. The composition of oils was analysed by gas chromatography (GC) and GC/mass spectrometry. The results indicated that the oils antifungal activity depended on the experimental assay used. The inhibiting effects of EO in vapour phase were generally higher than those in liquid state. According to both methods thyme red and clove were found to be the oils with the widest spectrum of activity against all fungi tested. Conclusions:  Despite the differences between the two methods, our results demonstrate that some EO are very active on dermatophytes and dematiaceous fungi. However, more data will be necessary to confirm this good in vitro efficacy. Significance and Impact of the Study:  This study could identify candidates of EO for developing alternative methods to control environmental and clinically undesirable filamentous fungi.

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BackgroundThe management of Candida infections faces many problems, such as a limited number of antifungal drugs, toxicity, resistance of Candida to commonly antifungal drugs, relapse of Candida infections, and the high cost of antifungal drugs. Though azole antifungal agents and derivatives continue to dominate as drugs of choice against Candida infections, there are many available data referring to the anticandidal activity of essential oils. Since we have previous observed a good antimicrobial activity of some essential oils against filamentous fungi, the aim of this study was to extend the research to evaluate the activity of the same oils on Candida albicans, C.glabrata and C.tropicalis clinical strains, as well as the effects of related components. Essential oils selection was based both on ethnomedicinal use and on proved antibacterial and/or antifungal activity of some of these oils. Fluconazole and voriconazole were used as reference drugs.MethodsThe minimum inhibitory concentration (MIC) and the minimal fungicidal concentration (MFC) of essential oils (thyme red, fennel, clove, pine, sage, lemon balm, and lavender) and their major components were investigated by the broth microdilution method (BM) and the vapour contact assay (VC).ResultsUsing BM, pine oil showed the best activity against all strains tested, though C.albicans was more susceptible than C.glabrata and C.tropicalis (MIC50-MIC90 = 0.06 %, v/v). On the contrary, sage oil displayed a weak activity (MIC50-MIC90 = 1 %, v/v). Thyme red oil (MIC50-MIC90 ≤ 0.0038 %, v/v for C.albicans and C.tropicalis, and 0.0078- < 0.015 %, v/v for C.glabrata), followed by lemon balm, lavender and sage were the most effective by VC. Carvacrol and thymol showed the highest activity, whereas linalyl acetate showed the lowest activity both by two methods. α-pinene displayed a better activity by BM than VC.ConclusionResults show a good activity of essential oils, mainly thymus red and pine oils, and their components carvacrol, thymol and α-pinene against Candida spp., including fluconazole/voriconazole resistant strains. These data encourage adequately controlled and randomized clinical investigations. The use in vapour phase could have additional advantages without requiring direct contact, resulting in easy of environmental application such as in hospital, and/or in school.

Biomaterial-associated infection (BAI), a clinical problem resulting in septic failure of joint replacement implants, is initiated by bacterial adhesion, often by Staphylococcus epidermidis. Ultra high molecular weight polyethylene (UHMWPE) is a material of choice for joint replacement; reducing the adhesion of S. epidermidis to the polymer could be a means to decrease infection. We examined the adhesion of two ATCC and one clinical strain of S. epidermidis to standard polyethylene (PE), vitamin E blended UHMWPE (VE-PE), and oxidized UHMWPE (OX-PE) after different incubation times: a significant (p < 0.01) decrease in the adhered staphylococci on VE-PE and a significantly higher incidence of the dislodged biofilm bacteria on OX-PE was observed compared with that registered on PE. With attenuated total reflectance (ATR)-FTIR spectroscopy before and after suspension in bacterial medium for 48 h, new absorptions were observed mainly in OX-PE, indicating adsorption of protein-like substances on the polymer surface. We hypothesized that the different hydrophilicity of the surfaces with different chemical characteristics influenced protein adsorption and bacterial adhesion. These results may have clinical implications concerning the prevention of septic loosening: the VE-PE could have the potential to reduce S. epidermidis adhesive ability if the preliminary data observed in these selected strains is further confirmed, as diversity among clinical strains is well known. ß

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