Tuning the local solvent composition at a drug carrier surface: the effect of dimethyl sulfoxide/water mixture on the photofunctional properties of hypericin-ß-lactoglobulin complexes.

Aggregation is a major problem for the anti-microbial photodynamic applications of hydrophobic photosensitizers since it strongly reduces the amount of singlet oxygen generated in aqueous solutions. Binding of hypericin (Hyp) to the milk whey protein ß-lactoglobulin (ßLG), occurring at the two hydrophobic cavities located at the interface of the protein homodimer, can be exploited to confer water-solubility and biocompatibility to the photosensitizer. The introduction of a small amount of the organic cosolvent dimethyl sulfoxide (DMSO) leads to a remarkable improvement of the photophysical properties of the complex Hyp-ßLG by increasing its fluorescence emission and singlet oxygen photosensitization quantum yields. Surprisingly, the ability of the complex to photo-inactivate bacteria of the strain Staphylococcus aureus is strongly reduced in the presence of DMSO, despite the higher yield of photosensitization. The reasons for this apparently contradictory behavior are investigated, providing new insights into the use of carrier systems for hydrophobic photosensitizers.

In Vitro Antimicrobial Photodynamic Therapy Against Trichophyton mentagrophytes Using New Methylene Blue as the Photosensitizer. / Terapia fotodinámica antimicrobiana in vitro aplicada sobre Trichophyton mentagrophytes con nuevo azul de metileno como fotosensibilizador.

INTRODUCTION AND OBJECTIVES: Antimicrobial photodynamic therapy combines the use of a photosensitizing drug with light and oxygen to eradicate pathogens. Trichophyton mentagrophytes is a dermatophytic fungus able to invade the skin and keratinized tissues. We have investigated the use of new methylene blue as the photosensitizing agent for antimicrobial photodynamic therapy to produce the in vitro inactivation of T mentagrophytes. MATERIAL AND METHODS: A full factorial design was employed to optimize the parameters for photoinactivation of the dermatophyte. The parameters studied were new methylene blue concentration, contact time between the photosensitizing agent and the fungus prior to light treatment, and the fluence of red light (wavelength, 620-645nm) applied. RESULTS: The minimum concentration of new methylene blue necessary to induce the death of all T. mentagrophytes cells in the initial suspension (approximate concentration, 106 colony forming units per milliliter) was 50µM for a fluence of 81J/cm2 after a contact time of 10minutes with the photosensitizing-agent. Increasing the concentration to 100µM allowed the fluence to be decreased to 9J/cm2. CONCLUSIONS: Comparison of our data with other published data shows that the susceptibility of T. mentagrophytes to antimicrobial photodynamic therapy with new methylene blue is strain-dependent. New methylene blue is a photosensitizing agent that should be considered for the treatment of fungal skin infections caused by this dermatophyte.

Simultaneous monitoring of Staphylococcus aureus growth in a multi-parametric microfluidic platform using microscopy and impedance spectroscopy.

We describe the design, construction, and characterization of a scalable microfluidic platform that allows continuous monitoring of biofilm proliferation under shear stress conditions. Compared to other previous end-point assay studies, our platform offers the advantages of integration into multiple environments allowing simultaneous optical microscopy and impedance spectroscopy measurements. In this work we report a multi-parametric sensor that can monitor the growth and activity of a biofilm. This was possible by combining two interdigitated microelectrodes (IDuEs), and punctual electrodes to measure dissolved oxygen, K+, Na+ and pH. The IDuE has been optimized to permit sensitive and reliable impedance monitoring of Staphylococcus aureus V329 growth with two- and four-electrode measurements. We distinguished structural and morphological changes on intact cellular specimens using four-electrode data modeling. We also detected antibiotic mediated effects using impedance. Results were confirmed by scanning electrode microscopy and fluorescence microscopy after live/dead cell staining. The bacitracin mediated effects detected with impedance prove that the approach described can be used for guiding the development of novel anti-biofilm agents to better address bacterial infection.

Survivability of Salmonella cells in popcorn after microwave oven and conventional cooking.

The survivability of Salmonella cells in popcorn preparation was determined for two distinct cooking methods. The first method used a standard microwave oven. The second method used conventional cooking in a pan. Prior to thermal processing in independent experiments, 12 suspensions in a range between 1x10(3) and 8x10(6) colony-forming units (CFU) per gram of Salmonella cells were inoculated in both raw microwave popcorn and conventional corn kernels. The influence of the initial concentration of Salmonella cells in the raw products and the lethal effects on Salmonella by thermal treatments for cooking were studied. Survival of Salmonella cells was determined in the thermally processed material by pre-enrichment and enrichment in selective medium, in accordance with the legislation for expanded cereals and cereals in flakes. Viable experimental contaminants were recovered from the conventionally cooked popcorn with initial inoculation concentrations of 9x10(4)cells/g or greater. Salmonella cell viability was significantly reduced after microwave oven treatment, with recoveries only from initial concentrations of 2x10(6)cells/g or superior.

Di-(2-ethylhexyl)phthalate in sewage sludge and post-treated sludge: quantitative determination by HRGC-MS and mass spectral characterization.

DEHP was quantified into sewage sludge, thermally dried sludge and compost samples from different areas of Catalonia (North East Spain) using high-resolution gas chromatography (HRGC) coupled to a mass spectrometry (MS). The aim of the work was to determine the evolution of this ubiquitous environmental contaminant along some post-treatment sludge processes, such as composting and thermally drying. DEHP concentration detected in some sludges are above the maximum limit suggested by the EC (100 ppm d.m.) for agricultural use. However, the composting and thermally drying reduce the amount of DEHP in sewage sludge to acceptable level for safe land application. The study was completed with the characterization and long-term observation of DEHP in sewage sludge, composted sludge and thermally dried sludge mixed with two types of soils. In all cases, the percentage of DEHP degraded was higher than 50% after 9 months of incubation.

Vaginal microbiota in healthy pregnant women and prenatal screening of group B streptococci (GBS).

The microbiota of the lower female genital tract was evaluated from vaginal swabs obtained from 623 healthy pregnant women at gestation periods of 35-40 weeks. Isolated and identified microorganisms were expressed as percentages of total samples. As expected, lactobacilli made up the dominant vaginal microbiota (70%). Enterobacteriaceae, mainly Escherichia coli, Klebsiella spp. and Proteus, were present in 38% of the samples, which might reflect the possible contamination of vaginal tract with rectal microorganisms. Candida albicans was present in 10% of healthy pregnant woman assayed. Streptoccocci (Streptococcus sp. and Enterococcus faecalis with 3% and 4%, respectively) and other gram-positive cocci (Staphylococcus sp., 5%), along with other microorgansisms such as Gardnerella vaginalis (5%) and Pseudomonas aeruginosa (2%) may represent a potential infection risk. Streptococcus agalactiae (group B streptococci beta-hemolytic, GBS) was detected in 7% of the samples. GBS infection is a leading cause of neonatal morbidity and mortality in the developed world. Furthermore, GBS was often co-isolated with C. albicans (54.5%) in the samples. A complete and detailed evaluation of the vaginal biota swab, with particular attention to the presence of potential pathogens such as GBS, is a preventive strategy that can provide useful information to obstetricians and gynecologist in managing the last days of pregnancy and delivery.

Vaginal microbiota in healthy pregnant women and prenatal screening of group B streptococci (GBS) / Microbiota vaginal durante la gestación en mujeres sanas y diagnóstico prenatal de estreptococos del grupo B (GBS)

The microbiota of the lower female genital tract was evaluated from vaginal swabs obtained from 623 healthy pregnant women at gestation periods of 35-40 weeks. Isolated and identified microorganisms were expressed as percentages of total samples. As expected, lactobacilli made up the dominant vaginal microbiota (70%). Enterobacteriaceae, mainly Escherichia coli, Klebsiella spp. and Proteus, were present in 38% of the samples, which might reflect the possible contamination of vaginal tract with rectal microorganisms. Candida albicans was present in 10% of healthy pregnant woman assayed. Streptoccocci (Streptococcus sp. and Enterococcus faecalis with 3% and 4%, respectively) and other gram-positive cocci (Staphylococcus sp., 5%), along with other microorgansisms such as Gardnerella vaginalis (5%) and Pseudomonas aeruginosa (2%) may represent a potential infection risk. Streptococcus agalactiae (group B streptococci beta-hemolytic, GBS) was detected in 7% of the samples. GBS infection is a leading cause of neonatal morbidity and mortality in the developed world. Furthermore, GBS was often co-isolated with C. albicans (54.5%) in the samples. A complete and detailed evaluation of the vaginal biota swab, with particular attention to the presence of potential pathogens such as GBS, is a preventive strategy that can provide useful information to obstetricians and gynecologist in managing the last days of pregnancy and delivery (AU)

Se evaluó la microbiota del tracto genital inferior femenino a partir de raspados vaginales obtenidos de 623 mujeres embarazadas en períodos de gestación de 35-40 semanas. Las cantitades de microorganismos aislados e identificados se expresan en porcentaje sobre la muestra total. Como se esperaba, los lactobacilos constituían la mayor parte de la microbiota vaginal (70 por ciento). En el 38 por ciento de las muestras se encontraron enterobacteriáceas, principalmente Escherichia coli, Klebsiella spp. y Proteus spp., lo cual refleja una posible contaminación del tracto vaginal con microorganismos rectales. Candida albicans estaba presente en el 10 por ciento de las mujeres sanas de la muestra. Los estreptococos (Streptococcus sp. y Enterococcus faecalis con un 3 por ciento y un 4 por ciento, respectivamente), junto con otros microorganismos tales como Gardnerella vaginalis (5 por ciento) y Pseudomonas aeruginosa (2 por ciento) representan un riesgo potencial de infección. Se detectó Streptococcus agalactiae (estreptococo del grupo B b-hemolítico, GBS) en el 7 por ciento de las muestras. La infección por GBS es una de las causas principales de morbidez neonatal y de mortalidad en el mundo desarrollado. Además, GBS suele ser co-aislado con C. albicans (54.5 por ciento) en las muestras. La evaluación e identificación de toda la biota en el raspado vaginal, con especial atención a patógenos como GBS, es una estrategia de prevención que proporciona información útil a los obstétricos y ginecólogos para controlar los últimos días del embarazo y el parto (AU)

Effect of the raw extracts of Arthrinium strains (Hyphomycetes, Dematiaceae) on the growth of some deleterious fungi in poultry feed.

In previous work the authors have shown that some species of the Arthrinium genus are characterized by being able to produce secondary metabolites with antibiotic activity. The aim of this study was to evaluate the effect of raw extracts of the growth of three different Arthrinium strains against Aspergillus flavus, Aspergillus nidulans, Fusarium moniliforme and Penicillium purpurogenum when they were present in poultry feed. The results showed that the extracts reduced the growth of Aspergillus flavus and Fusarium moniliforme but could not inhibit the development of Aspergillus nidulans. Only the raw extract of A. aureum inhibited the growth of Penicillium purpurogenum.

Effect of the raw extract of Arthrinium strains (Hyphomycetes, Dematiaceae) on the growth of pathogenic bacteria in poultry feed.

Poultry feed contains a significant reservoir of bacteria and is a possible source of Salmonella typhimurium, Staphylococcus aureus and Escherichia coli, which can potentially infect farm animals and humans. The objective of this study was to determine whether the extract obtained from the culture of some Arthrinium species was able to inhibit the growth of these bacteria. The results obtained showed that the raw extracts of Arthrinium aureum, Arthrinium serenensis and Arthrinium phaeospermum inhibited the growth of Escherichia coli in poultry feed. In some cases the percentage inhibition of the growth of Escherichia coli was > 80%. With the raw extract of Arthrinium in poultry feed, the rate of growth of S. typhimurium fell to between 50% and 80%. The raw extract of A. serenensis had the lowest inhibitory activity. S. aureus counts were not affected by any Arthrinium raw extracts.

Effect of ultraviolet light irradiation and nitrosoguanidine on viability of 46 strains of Arthrinium and their antibiotic production.

The ability of strains of the Arthrinium genus to inhibit microbial development has been previously described. In the present work different periods of mutagenic treatment using ultraviolet light, and of nitrosoguanidine treatment, on strains of Arthrinium were investigated. With nitrosoguanidine treatment the survival rate ranged from 2.17 to 8.78%. Mutant strains were only obtained with a higher antibiotic production in comparison with the wild-strain, when the mutagenic agent was UV light.

Virus-like particles in conidia and hypha of Arthrinium aureum.

This paper is the first report in the literature of the presence of virus-like particles in the conidia and hypha of Arthrinium aureum. These particles, detected with an electron microscope, are spherical and 52 nm in diameter.

Influence of the culture medium on the inhibitory activity of Arthrinium strains.

Modifications in the antibiotic capacity of Arthrinium strains when they were developed in culture media of various compositions were studied. The culture media used were 2% malt extract agar, Czapek-Dox agar, Sabouraud dextrose agar, oatmeal agar, Yoshimura's medium, mixed medium of salts, modified phytone agar, malt extract-yeast extract agar, potato dextrose agar, and Wickerham's medium. The inhibition values were compared with those obtained when the strains were developed in Wickerham's medium. The media which enhanced the production of inhibitory substances were potato dextrose agar and 2% malt extract agar.

Antimicrobial activity of essences from labiates.

Bacteria, filamentous fungi and yeasts were subjected to the action of Lavandula officinalis, Melissa officinalis and Rosmarinus officinalis essences in a steam phase, using a microatmospheric technique. Due to the methodology employed, L. officinalis essence was more active in filamentous fungi than the other essential oils studied. All three essences possessed a similar degree of activity against the micro-organisms tested, though a relatively higher activity was seen in the case of M. officinalis.

Presence of sterile hyphae in moulds: relationship with inhibitory activity.

The relationship involving the presence of sterile hyphae in moulds and their inhibitory activity on 34 micro-organisms was investigated. From the results it was evident that antimicrobial activity varied when morphological changes were observed in the cultures.

Chemical microanalysis of hyphae and conidia from Arthrinium aureum.

Analysis of the chemical composition of hyphae, conidia and chlamydospores of Arthrinium aureum enabled all sample constituents of > 23 kD molecular weight to be detected. Sulphur, chlorine, potassium and calcium were present in the hyphae and condia of A. aureum, and sulphur, potassium and calcium in the chlamydospores.

Keratinophilic fungi from soil of Brittany, France.

The Present work reports the study of the distribution of keratinophilic fungi isolated from 39 samples of soil collected in Brittany, France. Keratinophilic fungi were isolated from 35 (92.3%) of the samples studied. The most frequently found species wereFusarium moniliforme, Penicillium viridicatum and an unidentified species ofAcremonium. The other fungi isolated were members of the generaChrysosporium, Gliocladium, Mucor, Trichoderma andTrichophyton.

[Infectious external otitis: etiology in the Terrassa region, culture methods, and considerations on otomycosis]. / Otitis externas infecciosas: etiología en el área de Terrassa, métodos de cultivo y consideraciones sobre la otomicosis.

The etiology of infections of the outer ear was studied in the area of Terrassa (Barcelona) over a six-year period (1987-1992). A total of 1419 samples of ear discharge were processed. Traditional culture media were used to isolate the microorganisms as well as a modified culture medium prepared by us (APA). Usual methods were used to identify the microorganisms. The results show Pseudomonas aeruginosa to be the most frequently isolated microorganism. 76.5% of the otitis studied were unimicrobial and the presence of moulds or yeast was noted in 6.9% of samples. Otomycosis (5.9%) is one of the major pathological processes of the outer ear, and Aspergillus niger is the prime causal agent.