In vitro-to-in vivo extrapolation (IVIVE) by PBTK modeling for animal-free risk assessment approaches of potential endocrine-disrupting compounds.

While in vitro testing is used to identify hazards of chemicals, nominal in vitro assay concentrations may misrepresent potential in vivo effects and do not provide dose-response data which can be used for a risk assessment. We used reverse dosimetry to compare in vitro effect concentrations-to-in vivo doses causing toxic effects related to endocrine disruption. Ten compounds (acetaminophen, bisphenol A, caffeine, 17α-ethinylestradiol, fenarimol, flutamide, genistein, ketoconazole, methyltestosterone, and trenbolone) have been tested in the yeast estrogen screening (YES) or yeast androgen-screening (YAS) assays for estrogen and androgen receptor binding, as well as the H295R assay (OECD test guideline no. 456) for potential interaction with steroidogenesis. With the assumption of comparable concentration-response ratios of these effects in the applied in vitro systems and the in vivo environment, the lowest observed effect concentrations from these assays were extrapolated to oral doses (LOELs) by reverse dosimetry. For extrapolation, an eight-compartment Physiologically Based Toxicokinetic (PBTK) rat model based on in vitro and in silico input data was used. The predicted LOEL was then compared to the LOEL actually observed in corresponding in vivo studies (YES/YAS assay versus uterotrophic or Hershberger assay and steroidogenesis assay versus pubertal assay or generation studies). This evaluation resulted in 6 out of 10 compounds for which the predicted LOELs were in the same order of magnitude as the actual in vivo LOELs. For four compounds, the predicted LOELs differed by more than tenfold from the actual in vivo LOELs. In conclusion, these data demonstrate the applicability of reverse dosimetry using a simple PBTK model to serve in vitro-in silico-based risk assessment, but also identified cases and test substance were the applied methods are insufficient.

Microbiological quality assessment and validation of antimicrobials against unstressed or cold-stress adapted Salmonella and surrogate Enterococcus faecium on broiler carcasses and wings.

This study aims to evaluate the microbiological quality and efficacy of antimicrobials to inactivate unstressed or cold-stress adapted Salmonella and Enterococcus on broiler carcasses and wings processed at a small USDA-inspected slaughter facility in West Virginia. The first part of the study included 42 carcasses that were pre- and secondarily-enriched in bacterial media followed by streak-plating onto XLT-4 and HardyCHROM™-agar Salmonella and confirmation using an API20E-kit. The aerobic plate counts (APC), Escherichia coli (ECC), total coliforms (TCC), and yeast/molds were analyzed on petri-films. The second part of the study included fresh broiler carcasses and wings that were inoculated with unstressed and cold-stress-adapted (4 °C, 7-day) Salmonella Typhimurium and Tennessee, and Enterococcus faecium ATCC 8459 (5.5 to 6.0 log10CFU/mL) and later dipped into peroxyacetic acid (PAA; 1,000 ppm), lactic acid (LA; 5%), lactic and citric acid blend (LCA; 2.5%), and sodium hypochlorite (SH; 70 ppm) for 30 s without (carcasses) or with 2-min drainage (wings). The surviving bacteria were recovered onto non-selective and selective agar to analyze the total microbial population, Salmonella and Enterococcus. APC, TCC, and Yeast/Molds were 2.62, 1.08, and 2.37 log10CFU/mL on broiler carcasses, respectively. A total of 30 and 40% of the carcasses tested positive for Salmonella spp. and E. coli (0.48 to 1.70 log10CFU/mL), respectively. For carcasses, antimicrobial reductions of cold-stress-adapted cells of Salmonella and Enterococcus were greater (P < 0.05) than the unstressed cells. For wings, cold-stress-adapted Salmonella were more (P < 0.05) sensitive to antimicrobials than unstressed cells; however, unstressed and cold-stress-adapted Enterococcus behaved similarly (P > 0.05). The reduction of Salmonella and Enterococcus on carcasses and wings increased in the order of SH ≤ LCA < LA < PAA and irrespective of unstressed or cold-stress-adapted cells. Applying post-chilling antimicrobial dipping treatments could be an intervention approach to control Salmonella on locally processed broilers. In addition, Enterococcus faecium could be a Salmonella surrogate for in-plant validation studies.

Epidemiology of antifungal resistance in human pathogenic yeasts: current viewpoint and practical recommendations for management.

In this review, we describe the epidemiology and clinical significance of resistance in Candida spp. and other non-Cryptococcus yeasts. The rise in echinocandin resistance, azole resistance and cross-resistance to two or more antifungal classes [multidrug resistance (MDR)] has been a worrisome trend, mainly in US large tertiary and oncology centres, particularly as it relates to Candida glabrata. Candida kefyr is also a concern as it can be resistant to echinocandins and polyenes, especially in patients with haematological malignancies. Lately, Candida auris has drawn a lot of attention: this uncommon Candida spp. is the first globally emerging fungal pathogen that exhibits MDR and strong potential for nosocomial transmission. Its almost simultaneous spread in four continents could be indicative of increasing selection pressures from the use of antifungal agents. Echinocandin non-susceptibility is also common among non-Candida, non-Cryptococcus yeasts. As Candida resistance patterns reflect, in part, institutional practices of antifungal administration, the benefits of antifungal stewardship protocols are increasingly recognised and endorsed in recent guidelines. Development of rapid diagnostic methods for detecting or ruling out the presence of candidaemia and antifungal resistance, as well as discovery of novel antifungals, are key priorities in medical mycology research.

Performance assessment of two lysis methods for direct identification of yeasts from clinical blood cultures using MALDI-TOF mass spectrometry.

In cases of fungal infection of the bloodstream, rapid species identification is crucial to provide adapted therapy and thereby ameliorate patient outcome. Currently, the commercial Sepsityper kit and the sodium-dodecyl sulfate (SDS) method coupled with MALDI-TOF mass spectrometry are the most commonly reported lysis protocols for direct identification of fungi from positive blood culture vials. However, the performance of these two protocols has never been compared on clinical samples. Accordingly, we performed a two-step survey on two distinct panels of clinical positive blood culture vials to identify the most efficient protocol, establish an appropriate log score (LS) cut-off, and validate the best method. We first compared the performance of the Sepsityper and the SDS protocols on 71 clinical samples. For 69 monomicrobial samples, mass spectrometry LS values were significantly higher with the SDS protocol than with the Sepsityper method (P < .0001), especially when the best score of four deposited spots was considered. Next, we established the LS cut-off for accurate identification at 1.7, based on specimen DNA sequence data. Using this LS cut-off, 66 (95.6%) and 46 (66.6%) isolates were correctly identified at the species level with the SDS and the Sepsityper protocols, respectively. In the second arm of the survey, we validated the SDS protocol on an additional panel of 94 clinical samples. Ninety-two (98.9%) of 93 monomicrobial samples were correctly identified at the species level (median LS = 2.061). Overall, our data suggest that the SDS method yields more accurate species identification of yeasts, than the Sepsityper protocol.

Use of natural antimicrobials to improve the quality characteristics of fresh "Phyllo" - A dough-based wheat product - Shelf life assessment.

This study explores the effects of chitosan and natamycin on the quality of fresh "Phyllo" - a dough-based wheat product, by monitoring the microbiological, physicochemical and sensory parameters. Four different lots of phyllo samples stored under aerobic packaging conditions, in the absence or presence of the aforementioned antimicrobials, were prepared and stored at 4 °C. Microbiological data suggested that, the combination of chitosan and natamycin resulted in significant reductions (1-3 log cfu/g) of the microbial species examined (mesophilic total viable counts; TVC), yeasts/molds, psychrotrophic and lactic acid bacteria (LAB), Enterobacteriaceae and coliforms) by day 10. The pH values of treated phyllo samples were lower on final day 10, as compared to the untreated phyllo, and of the Hunter color parameters (L*, b* and a*) that were evaluated, mostly the combined treatment of chitosan and natamycin maintained the original lightness (L*) and color (yellowness) stability (b*) of phyllo product during the storage period. Sensory data, based on overall acceptability (mean values of appearance and odor) scores confirmed the superiority of combined treatment of chitosan and natamycin, resulting in almost a doubling of the shelf-life of fresh phyllo, while retaining excellent sensorial characteristics (appearance and odor) even on final storage day (10).

Biological Characterization and in Vivo Assessment of the Activity of a New Synthetic Macrocyclic Antifungal Compound.

We recently identified a novel family of macrocyclic amidinoureas showing potent antifungal activity against Candida spp. In this study, we demonstrate the fungicidal effect of these compounds as well as their killing activity in a dose-dependent manner. Transcriptional analysis data indicate that our molecules induce a significant change in the transcriptome involving ATP binding cassette (ABC) transporter genes. Notably, experiments against Candida albicans mutants lacking those genes showed resistance to the compound, suggesting the involvement of ABC transporters in the uptake or intracellular accumulation of the molecule. To probe the mode of action, we performed fluorescence microscopy experiments on fungal cells treated with an ad-hoc synthesized fluorescent derivative. Fluorescence microscopy images confirm the ability of the compound to cross the membrane and show a consistent accumulation within the cytoplasm. Finally, we provide data supporting the in vivo efficacy in a systemic infection murine model setup with a drug-resistant strain of C. albicans.

In vitro toxicity assessment of sediment samples from Huangpu River and Suzhou River, Shanghai, China.

Sediments are the ultimate sink for many toxic organic contaminants released into aquatic environment. The present study evaluated the toxicity effect of 13 surface sediment samples from Huangpu River and Suzhou River, East China using two-hybrid yeast bioassays for estrogenic and thyroidal effects and H4IIE rat hepatoma cell bioassay for ethoxyresorufin O-deethylase (EROD) activity. Toxicity was expressed as 17ß-estradiol equivalent (E2-EQ), 3,3',5-triiodothyronine equivalent (T3-EQ), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalent (TEQ). At the same time, the causality between the observed EROD activity and concentrations of polycyclic aromatic hydrocarbons (PAHs) was examined. The results showed that the total estrogenic effects in sediments ranged from 0.06 to 1.21 µg E2-EQ kg(-1) dry weight (dw), the thyroidal effects ranged from 4.68 to 69.9 µg T3-EQ kg(-1) dw, and significantly positive correlations were found between lgT3-EQs and lgE2-EQs. The AhR agonist effects varied from 26.5 to 148.3 ng TEQ kg(-1) dw. Chemical analysis-derived TEQs contributed by PAHs ranged from 13.8 to 66.0 ng kg(-1) dw accounting for 27.2-109.9 % with mean of 48.9 % of TEQbio, indicating that PAHs made important contributions to the EROD effects of sediment extracts from the two rivers. The present study would provide meaningful information for further analysis and risk evaluation for organic pollutants in Huangpu River and Suzhou River.

Physicochemical and antimicrobial properties of copaiba oil: implications on product quality control.

BACKGROUND: The copaiba oil is a common natural product used in cosmetic industry and as a nutraceutical product. However, lack of quality control and scarce knowledge about its antimicrobial activity is a point of concern. The proposal of this study was to investigate the physicochemical properties and the antimicrobial activity of five commercial brands of copaiba oil. METHODS: Acidity and ester index, refractory index, solubility in alcohol, and thin layer chromatography were performed to verify the physicochemical properties of five commercial copaiba oils sold in local pharmacies. Ultra performance liquid chromatography coupled with diode-array detection and electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-DAD/ESI-Q-TOF-MS) was used to investigate diterpene acids while the volatile compounds were analysed by gas chromatography-mass spectrometry (GC-MS). Antibacterial and antifungal activities were also evaluated by agar diffusion technique; and minimal inhibitory concentration and maximal bactericidal concentration were defined for each sample and bacteria. RESULTS: The physical-chemical analysis revealed heterogeneity between all samples analysed. The A1 sample showed characteristics of copaiba oil and was mainly composed by hydrocarbon sesquiterpenes (29.95% ß-bisabolene, 25.65% Z-α-bergamotene and 10.27% ß-cariophyllene). Among diterpene acids, the UPLCDAD/ESI-Q-TOF-MS data are compatible with presence of copalic and/or kolavenic acid (m/z 305 [M + H]+). Candida albicans was sensitive to almost all samples at high concentration and Saccaromyces. Cerevisiae showed sensitivity to A1 sample at 100 mg/mL. Although variable, all samples showed antibacterial activity. Significant activity was seen for A3 (19.0 ±0 and 15.6 ±0.5 mm), A4 (16.6 ±0.5 and 15.6 ±0 mm), and A5 (17.1 ±0 and 17.1 ±0 mm) on Staphylococcus saprophyticus and S. aureus, respectively. All samples were active against Klebsiella pneumoniae showing ≥15 mm diameter halo inhibition; and only A2 was active against Eschirichia coli. Phytopatogens tested revealed resistance of Ralstonia solanacearum CGH12 to all samples and susceptibility of Xcv 112 strain of Xanthomonas campestris pv campestris to almost all samples. MIC and MMC showed bacteriostatic effect against clinical interest bacteria and bactericidal effect against phytopatogens. CONCLUSIONS: The results from physicochemical analysis reinforce the fact that it is imperative to include simple conventional methods in the analysis of oil products. The analysis of copaiba oil gives safe products and purity which ensure products with quality. Also, since copaiba oil is an over-the-counter product the results indicate that pharmacosurveillance must be improved by the governmental regulation agency to avoid microorganism resistance selection and to achieve better international quality products.

Biotests for environmental quality assessment of composted sewage sludge.

The quality of sewage sludge-based products, such as composts and growth media, is affected by the contamination of sewage sludge with, potentially, hundreds of different substances. Therefore, it is difficult to achieve the reliable environmental quality assessment of sewage sludge-based products solely based on chemical analysis. In the present work, we demonstrate the use of the kinetic luminescent bacteria test (ISO 21338) to evaluate acute toxicity and the Vitotox™ test to monitor genotoxicity of sewage sludge and composted sewages sludge. In addition, endocrine-disrupting and dioxin-like activity was studied using yeast-cell-based assays. The relative contribution of industrial waste water treated at the Waste Water Treatment Plants led to elevated concentrations of polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) in sewage sludge. The effect of elevated amounts of organic contaminants could also be identified with biotests able to demonstrate higher acute toxicity, genotoxicity, and potential for endocrine-disruptive properties. Additional extraction steps in kinetic luminescent bacteria test with DMSO and hexane increased the level of toxicity detected. Composting in a pilot-scale efficiently reduced the amounts of linear alkylbenzensulphonates (LASs), nonylphenols and nonylphenolethoxylates (NPE/NPs) and PAH with relative removal efficiencies of 84%, 61% and 56%. In addition, decrease in acute toxicity, genotoxicity and endocrorine-disrupting and dioxin-like activity during composting could be detected. However, the biotests did have limitations in accessing the ecotoxicity of test media rich with organic matter, such as sewage sludge and compost, and effects of sample characteristics on biotest organisms must be acknowledged. The compost matrix itself, however, which contained a high amount of nutrients, bark, and peat, reduced the sensitivity of the genotoxicity tests and yeast bioreporter assays.

Metabolic plasticity and the energy economizing effect of ibogaine, the principal alkaloid of Tabernanthe iboga.

ETHNOPHARMACOLOGICAL RELEVANCE: The root bark of iboga plant-Tabernanthe iboga has been used traditionally in Central Africa as a psychoactive substance in religious rituals, while in smaller doses it is appreciated due to its stimulant properties. The iboga root bark, iboga extract or pure ibogaine are being recognized in the West as an anti-addiction remedy and their use is increasing. AIM OF THE STUDY: Our previous studies have demonstrated a transient ATP pool reduction under ibogaine accompanied by the induction of energy metabolism related enzymes. The present study aimed to find the cause of this energy deprivation and to foresee its immediate and long-term impact on metabolism. The overall project is designed to disclose the common mechanism of action at these seemingly diverse indications for iboga use, to predict eventual adverse effects and to build the grounds for its safe and beneficial utilization. MATERIALS AND METHODS: The rate of carbon dioxide (CO(2)) as a marker of energy metabolism in stationary yeast model under aerobic conditions in the presence of ibogaine at concentration of 1, 4 and 20mg/l was measured for 5h by gas chromatography. The overall oxidative load was determined fluorimetrically by 2',7'-dichlorofluorescein diacetate (H(2)DCFDA) and in vitro antioxidant properties of ibogaine were defined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) test. RESULTS: The CO(2) production under ibogaine was temporarily increased in a dose dependent manner. The increased energy consumption as an early effect of ibogaine was proven by the fact that in spite of energy mobilization, the ATP pool has been simultaneously decreased. Although increased cellular respiration co-produces reactive oxygen species (ROS), the overall oxidative load was significantly lowered by ibogaine. Since ibogaine does not show any significant in vitro antioxidant properties, the results indicate its stimulating influence on physiological oxidative stress defence system. CONCLUSION: Ibogaine triggers remodeling of the housekeeping metabolism. Under the initial energy cost it results in increased efficacy of physiological antioxidative systems, which reduce oxidative damage and lowers basal metabolic needs. Together with induced catabolic enzymes they set a new metabolic equilibrium that saves energy and makes it easily available in case of extra needs. While healthy organism profits from improved fitness and mental performance and can withstand higher stress without risking a disease, due to the same principle ibogaine provides beneficial support at the recovery after diseases including addiction syndrome.

Application of proanthocyanidins from peanut skins as a natural yeast inhibitory agent.

UNLABELLED: Proanthocyanidins were extracted from peanut skins and investigated for their antimicrobial activity against Saccharomyces cerevisiae, Zygosaccharomyces bailii, and Zygosaccharomyces bisporus in traditional growth media (Sabouraud Dextrose and Maltose broth) and a simulated apple juice beverage. Peanut skins extracts (PSE) were prepared through a multisolvent extraction procedure. The PSE extended the lag phase growth of the 3 yeasts studied at a concentration of 1 mg/mL and at 10 mg/mL yeast growth was totally inhibited for 120 h. PSE was fractionated by normal phase high performance liquid chromatography and the active components/fractions were determined. Compounds present in the fractions were identified by liquid chromatography-mass spectrometry to determine the compounds responsible for inhibition. Fractions consisting mostly of A-type proanthocyanidin dimers, trimers, and tetramers showed the highest percent inhibition toward the yeasts tested in this study. Both optical density (OD) and standard enumeration plating methods were performed in this study. The OD method led to an overestimation of the inhibitory effects of PSE, the 2 methods agreed in respect to treatment effects but not the severity of the inhibition. PRACTICAL APPLICATION: There is a growing consumer demand for "fresh like" products containing reduced amounts of chemical preservatives without compromising food safety and quality. Therefore, the goal of this study was to determine if an extract of peanut skins containing flavonoid rich compounds could function as a natural antimicrobial in a model beverage system. Proteins were removed through the process of producing the peanut skin extract, thus it is unlikely to contain peanut allergens. The antimicrobial compounds mentioned in this study were successfully integrated into a model beverage system, and were found to have antimicrobial effect. However, the incorporation of these compounds would likely lead to negative sensory attributes at the concentration needed to achieve an appreciable antimicrobial effect alone.

An assessment of the potential of the microbial assay for risk assessment (MARA) for ecotoxicological testing.

Rapid microscale toxicity tests make it possible to screen large numbers of compounds and greatly simplify toxicity identification evaluation and other effect directed chemical analyses of effluents or environmental samples. Tests using Vibrio fischeri (such as Microtox®) detect toxicants that cause non-specific narcosis, but are insensitive to other important classes of contaminants. The microbial assay for risk assessment (MARA) is a 24 h multi-species test that seeks to address this problem by using a battery of ten bacteria and a fungus. But there has been little independent evaluation of this test, and there is no published information on its sensitivity to pesticides. Here, we assess the performance of MARA using a range of toxicants including reference chemicals, fungicides and environmental samples. Mean MARA microbial toxic concentrations and IC(20)s (20% Inhibitory concentrations) indicate the toxicant concentrations affecting the more sensitive micro-organisms, while the mean IC(50) (50% Inhibitory concentration) was found to be the concentration that was toxic to most MARA species. For the two fungicides tested, the yeast (Pichia anomalia) was the most sensitive of the ten MARA species, and was more sensitive than the nine other yeasts tested. The test may be particularly valuable for work with fungicides. Mean MARA IC(50)s were comparable to values for nine other yeast species and the lowest individual IC(50)s for each toxicant were comparable to reported IC(50)s for Daphnia magna, Selenastrum capricornutum and Microtox® bioassays. MARA organisms exhibited more variable sensitivities, with the most sensitive organism being different for different samples, enhancing the likelihood of toxicity detection and giving a toxicity "fingerprint" that may help identify toxicants. The test, therefore, has great potential and would be valuable for ecotoxicological testing of pollutants.

Assessment of trace organic chemical removal by a membrane bioreactor using gas chromatography/mass spectrometry and a yeast screen bioassay.

A membrane bioreactor (MBR) was assessed for the removal of estrogens, androgens, and a selection of pharmaceuticals and personal care products. The biomass and aqueous components of the MBR were investigated to determine whether removal was by biodegradation or by adsorption to the biomass. Removal was monitored using chemical analysis by gas chromatography/mass spectrometry (GC-MS) as well as biological analysis using estrogenic and androgenic yeast assays. Results showed that the MBR was effective in removing the compounds of concern from raw influent with removal rates between 78 and 99%. Removal efficiencies were comparable or better than those reported for conventional activated sludge systems, which was attributed to the relatively high sludge retention time of the MBR. The biomass component showed significant concentrations of salicylic acid, triclosan, and 4-tert-octylphenol. Estrogenic and androgenic activity was also measured in the biomass. Estrone was identified as the main compound responsible for the estrogenic activity. It was concluded that the main removal pathway was biodegradation, but sorption to biomass may also be important, particularly for triclosan and 4-tert-octylphenol.

Quantitative phenotyping via deep barcode sequencing.

Next-generation DNA sequencing technologies have revolutionized diverse genomics applications, including de novo genome sequencing, SNP detection, chromatin immunoprecipitation, and transcriptome analysis. Here we apply deep sequencing to genome-scale fitness profiling to evaluate yeast strain collections in parallel. This method, Barcode analysis by Sequencing, or "Bar-seq," outperforms the current benchmark barcode microarray assay in terms of both dynamic range and throughput. When applied to a complex chemogenomic assay, Bar-seq quantitatively identifies drug targets, with performance superior to the benchmark microarray assay. We also show that Bar-seq is well-suited for a multiplex format. We completely re-sequenced and re-annotated the yeast deletion collection using deep sequencing, found that approximately 20% of the barcodes and common priming sequences varied from expectation, and used this revised list of barcode sequences to improve data quality. Together, this new assay and analysis routine provide a deep-sequencing-based toolkit for identifying gene-environment interactions on a genome-wide scale.

Quality assessment of lager brewery yeast samples and strains using barley malt extracts with anti-yeast activity.

Membrane active anti-yeast compounds, such as antimicrobial peptides and proteins, cause yeast membrane damage which is likely to affect yeast vitality and fermentation performance, parameters which are notoriously difficult to analyse. In this work the sensitivity of lager brewery yeast strains towards barley malt extracts with anti-yeast activity was assessed with an optimised assay. It was found that yeast, obtained directly from a brewery, was much more sensitive towards the malt extracts than the same yeast strain propagated in the laboratory. Sensitivity to the malt extracts increased during the course of a laboratory scale fermentation when inoculated with brewery yeast. As the assay was able to differentiate yeast samples with different histories, it shows promise as a yeast quality assay measuring the yeast's ability to withstand stress which can be equated to vitality. The assay was also able to differentiate between different lager yeast strains of Saccharomyces cerevisiae propagated in the laboratory when challenged with a number of malt extracts of varying anti-yeast activity. The assessment of yeast strains in the presence of malt extracts will lead to the identification of yeast strains with improved quality/vitality that can withstand malt-associated anti-yeast activity during brewery fermentations.

Activities of antifungal agents against yeasts and filamentous fungi: assessment according to the methodology of the European Committee on Antimicrobial Susceptibility Testing.

We compared the activities of antifungal agents against a wide range of yeasts and filamentous fungi. The methodology of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) for yeasts and spore-forming molds was applied; and a total of 349 clinical isolates of Candida spp., other yeast species, Aspergillus spp., and nondermatophyte non-Aspergillus spp. were investigated. The average geometric mean (GM) of the MICs of the various drugs for Candida spp. were as follows: amphotericin B (AMB), 0.55 microg/ml; liposomal amphotericin B (l-AMB); 0.35 microg/ml; itraconazole (ITC), 0.56 microg/ml; voriconazole (VRC), 0.45 microg/ml; posaconazole (POS), 0.44 microg/ml; and caspofungin (CPF), 0.45 microg/ml. The data indicated that the majority of Candida spp. were susceptible to the traditional and new antifungal drugs. For Aspergillus spp., the average GM MICs of AMB, l-AMB, ITC, VRC, POS, and CPF were 1.49 microg/ml, 1.44 microg/ml, 0.65 microg/ml, 0.34 microg/ml, 0.25 microg/ml, and 0.32 microg/ml, respectively. For the various zygomycetes, the average GM MICs of AMB, l-AMB, ITC, and POS were 1.36 microg/ml, 1.42 microg/ml, 4.37 microg/ml, and 1.65 microg/ml, respectively. Other yeastlike fungi and molds displayed various patterns of susceptibility. In general, the minimal fungicidal concentrations were 1 to 3 dilutions higher than the corresponding MICs. POS, AMB, and l-AMB showed activities against a broader range of fungi than ITC, VRC, and CPF did. Emerging pathogens such as Saccharomyces cerevisiae and Fusarium solani were not killed by any drug. In summary, the EUCAST data showed that the in vitro susceptibilities of yeasts and filamentous fungi are variable, that susceptibility occurs among and within various genera and species, and that susceptibility depends on the antifungal drug tested. AMB, l-AMB, and POS were active against the majority of pathogens, including species that cause rare and difficult-to-treat infections.

ISTA13--international interlaboratory comparative evaluation of microbial assay for risk assessment (MARA).

The microbial assay for risk assessment (MARA) is an innovative system based on an array of 11 different microbial species freeze-dried in a 96-well micro-titer plate. Developed for testing the toxicity of chemicals, mixtures, and environmental samples, the assay employs species of a taxonomically diverse range. In addition to 10 prokaryotic species, a eukaryote (yeast) is included in the range. The MARA's innate scope of a multi-dimensional test allows determination of toxicity based on a unique assay fingerprint or index, numerically expressed as the mean microbial toxic concentration (MTC). The most significant potential of the test is in the additional inference that can be conveyed to the toxicity evaluation because of the presence of each of the constituent species. The performance of MARA was evaluated to ascertain its capability and potential scope in an intralaboratory trial. Sensitivity to toxicants and different environmental samples was assessed. Evaluation included comparison with other tests; namely Microtox, invertebrate (Daphnia magna and Thamnocephalus platyurus) microbiotests, and respiration- and nitrification-inhibition tests. MARA's performance was further assessed with the implementation of an international interlaboratory trial. This involved the participation of 13 laboratories ranging from academic establishments to regulatory agencies. The results of the testing will be presented with assessment of the extent of variability and specific assay components. The trial evaluation indicated that performance of the assay was satisfactory and the results were within the acceptable range. MARA is a robust multispecies assay offering scope for toxicity assessment of a diverse range of samples.

Risk assessment for organic trace compounds in wastewater: comparison of conventional and advanced treatment.

The elimination of organic trace compounds in municipal wastewater was analysed at three German wastewater treatment plants. Additionally, the effects of advanced treatment, membrane filtration, adsorption and oxidation processes were investigated. To assess the ecotoxicity of effluents, a number of tools were used: substance-specific evaluation, case studies for combined effects and risk assessment on the basis of cumulative parameters. The results of the research projects revealed that aquatic environmental risks can be reduced significantly using advanced treatment technologies for wastewater treatment plants.

Antifungal agents: mode of action in yeast cells.

Different kinds of mycoses, especially invasive, have become an important public health problem as their incidence has increased dramatically in the last decades in relation to AIDS, hematological malignancies, transplant recipients and other immunosuppressed individuals. Management of fungal infections is markedly limited by problems of drug safety, resistance and effectiveness profile. Current therapy for invasive mycoses uses a relatively reduced number of antifungal drugs, such as amphotericin B, fluconazole and itraconazole. Other new antifungal agents from old and new chemical families, like voriconazole, posaconazole, ravuconazole, caspofungin and micafungin, have been introduced into the armamentarium for fungal infections management. This review is focused on the mode of action of those antifungal drugs used against pathogenic yeasts. The interaction of amphotericin B with ergosterol and other membrane sterols results in the production of aqueous pores of drug and the ergosterol biosynthetic pathway is the target of the allylamines, phenylmorpholines and azole antifungal agents. The main molecular target of azole antifungals is the cytochrome P-450 protein Erg11p/Cyp51p. Echinocandins, a new class of antifungal drugs, are fungal secondary metabolites that act against beta-1-3-D-glucan synthesis. The phenylmorpholines, of which amorolfine is the sole representative in human therapy, affect two targets in the ergosterol pathway: Erg24p (delta 14 reductase) and Erg2p (delta 8-delta 7 isomerase). The sordarins group are protein synthesis inhibitors that work by blocking the function of fungal translation elongation factor 2. Other protein inhibitors are zofimarin, BE31045, SCH57504, xylarin, hypoxysordarin and GR135402. In order to overcome the problems derived from the exploitation of azole drugs, macrolides and echinocandins, novel targets were explored. Proposed antifungal drugs have been developed against potential targets like the N-myristylation of fungal proteins, with inhibitors like myristate and histidine analogues or myristoylpeptide derivatives, aminobenzothiazoles, quinolines and benzofurans. Polymerization of cell wall carbohydrates from uridine di-phospho sugars is another potential target.