In vitro activity of tea-tree oil against clinical skin isolates of meticillin-resistant and -sensitive Staphylococcus aureus and coagulase-negative staphylococci growing planktonically and as biofilms

The susceptibility of Staphylococcus aureus [meticillin-resistant (MRSA) and meticillin-sensitive (MSSA)] and coagulase-negative staphylococci (CoNS), which respectively form part of the transient and commensal skin flora, to tea-tree oil (TTO) was compared using broth microdilution and quantitative in vitro time-kill test methods. MRSA and MSSA isolates were significantly less susceptible than CoNS isolates, as measured by both MIC and minimum bactericidal concentration. A significant decrease in the mean viable count of all isolates in comparison with the control was seen at each time interval in time-kill assays. However, the only significant difference in the overall mean log(10) reduction in viable count between the groups of isolates was between CoNS and MSSA at 3 h, with CoNS isolates demonstrating a significantly lower mean reduction. To provide a better simulation of in vivo conditions on the skin, where bacteria are reported to grow as microcolonies encased in glycocalyx, the bactericidal activity of TTO against isolates grown as biofilms was also compared. Biofilms formed by MSSA and MRSA isolates were completely eradicated following exposure to 5 % TTO for 1 h. In contrast, of the biofilms formed by the nine CoNS isolates tested, only five were completely killed, although a reduction in viable count was apparent for the other four isolates. These results suggest that TTO exerts a greater bactericidal activity against biofilm-grown MRSA and MSSA isolates than against some biofilm-grown CoNS isolates.

Neutral gas depletion mechanisms in dense low-temperature argon plasmas

Neutral gas depletion mechanisms are investigated in a dense low-temperature argon plasma-an inductively coupled magnetic neutral loop (NL) discharge. Gas temperatures are deduced from the Doppler profile of the 772.38 nm line absorbed by argon metastable atoms. Electron density and temperature measurements reveal that at pressures below 0.1 Pa, relatively high degrees of ionization (exceeding 1%) result in electron pressures, p(e) = kT(e)n(e), exceeding the neutral gas pressure. In this regime, neutral dynamics has to be taken into account and depletion through comparatively high ionization rates becomes important. This additional depletion mechanism can be spatially separated due to non-uniform electron temperature and density profiles (non-uniform ionization rate), while the gas temperature is rather uniform within the discharge region. Spatial profiles of the depletion of metastable argon atoms in the NL region are observed by laser induced fluorescence spectroscopy. In this region, the depletion of ground state argon atoms is expected to be even more pronounced since in the investigated high electron density regime the ratio of metastable and ground state argon atom densities is governed by the electron temperature, which peaks in the NL region. This neutral gas depletion is attributed to a high ionization rate in the NL zone and fast ion loss through ambipolar diffusion along the magnetic field lines. This is totally different from what is observed at pressures above 10 Pa where the degree of ionization is relatively low (

Deposition and depletion of five anticoccidials in eggs

Anticoccidials are compounds that are widely used as feed additives to prevent and treat coccidiosis. They are licensed for use in a prescribed concentration and during a certain time interval for broilers and pullets but not for laying hens. It was shown in the past that carry-over at the feeding mill is found to be the main reason for the presence of residues in eggs. An animal experiment was set up to investigate the effect of carry-over at the feeding mill on the presence of residues of anticoccidials in eggs. For the compounds diclazuril, robenidine, halofuginone and nicarbazin in combination with narasin, two concentration levels were tested: the maximum allowed concentration for broilers (100%) and a concentration corresponding to 5% carry-over during feed preparation. Also dimetridazole was included in the experiment but only at one concentration level. Eggs were sampled during treatment (14 days) and for a period of 30 days after withdrawal of the anticoccidial-containing feed. Residues were determined, and deposition and depletion curves were generated. Analyses were performed by ELISA and LC-MS/MS. For all compounds, substantial residues could be found in the 5% groups, which points out the risk of carry-over at the feeding mill. The distribution of the residues between egg yolk and white was determined by analyzing both fractions.

Steam reforming of model compounds and fast pyrolysis bio-oil on supported noble metal catalysts

The production of hydrogen by steam reforming of bio-oils obtained from the fast pyrolysis of biomass requires the development of efficient catalysts able to cope with the complex chemical nature of the reactant. The present work focuses on the use of noble metal-based catalysts for the steam reforming of a few model compounds and that of an actual bio-oil. The steam reforming of the model compounds was investigated in the temperature range 650-950 degrees C over Pt, Pd and Rh supported on alumina and a ceria-zirconia sample. The model compounds used were acetic acid, phenol, acetone and ethanol. The nature of the support appeared to play a significant role in the activity of these catalysts. The use of ceria-zirconia, a redox mixed oxide, lead to higher H-2 yields as compared to the case of the alumina-supported catalysts. The supported Rh and Pt catalysts were the most active for the steam reforming of these compounds, while Pd-based catalysts poorly performed. The activity of the promising Pt and Rh catalysts was also investigated for the steam reforming of a bio-oil obtained from beech wood fast pyrolysis. Temperatures close to, or higher than, 800 degrees C were required to achieve significant conversions to COx and H-2 (e.g., H-2 yields around 70%). The ceria-zirconia materials showed a higher activity than the corresponding alumina samples. A Pt/ceria-zirconia sample used for over 9 h showed essentially constant activity, while extensive carbonaceous deposits were observed on the quartz reactor walls from early time on stream. In the present case, no benefit was observed by adding a small amount of O-2 to the steam/bio-oil feed (autothermal reforming, ATR), probably partly due to the already high concentration of oxygen in the bio-oil composition. (c) 2005 Elsevier B.V. All rights reserved.

A randomized controlled trial of tea tree oil (5%) body wash versus standard body wash to prevent colonization with methicillin-resistant Staphylococcus aureus (MRSA) in critically ill adults: research protocol

Background
Over the past ten years MRSA has become endemic in hospitals and is associated with increased healthcare costs. Critically ill patients are most at risk, in part because of the number of invasive therapies that they require in the intensive care unit (ICU). Washing with 5% tea tree oil (TTO) has been shown to be effective in removing MRSA on the skin. However, to date, no trials have evaluated the potential of TTO body wash to prevent MRSA colonization or infection. In addition, detecting MRSA by usual culture methods is slow. A faster method using a PCR assay has been developed in the laboratory, but requires evaluation in a large number of patients.

Methods/Design
This study protocol describes the design of a multicentre, phase II/III prospective open-label randomized controlled clinical trial to evaluate whether a concentration of 5% TTO is effective in preventing MRSA colonization in comparison with a standard body wash (Johnsons Baby Softwash) in the ICU. In addition we will evaluate the cost-effectiveness of TTO body wash and assess the effectiveness of the PCR assay in detecting MRSA in critically ill patients. On admission to intensive care, swabs from the nose and groin will be taken to screen for MRSA as per current practice. Patients will be randomly assigned to be washed with the standard body wash or TTO body wash. On discharge from the unit, swabs will be taken again to identify whether there is a difference in MRSA colonization between the two groups.

Discussion
If TTO body wash is found to be effective, widespread implementation of such a simple colonization prevention tool has the potential to impact on patient outcomes, healthcare resource use and patient confidence both nationally and internationally.

Trial Registration
[ISRCTN65190967]

Oil on Troubled Waters-Multinational Corporations and Realising Human Rights in the Developing World with Particular Reference to Nigeria

This article examines the current state of tension in the Niger Delta of Nigeria. It locates the current unrest in the continued denial of economic, social and cultural rights to the oil-rich communities in the area. The author argues that this denial happened with the complicity and acquiescence of the international community. The Nigerian government as well as multinational corporations operating in the area have not been responsive to the development needs of the people. The article argues that, although the primary obligation for realising the economic, social and cultural rights of host communities rests on the government, multi-national corporations in developing countries, considering their awesome resources and influence on government policies, should be similarly obligated to respect, promote and protect those rights.