The low global burden of trichinellosis: evidence and implications.

Trichinellosis is a cosmopolitan foodborne disease that may result in severe health disorders and even death. Despite international awareness of the public health risk associated with trichinellosis, current data on its public health impact are still lacking. Therefore we assessed, for the first known time, the global burden of trichinellosis using the Disability-Adjusted Life Year metric. The global number of Disability-Adjusted Life Years due to trichinellosis was estimated to be 76 per billion persons per year (95% credible interval: 38-129). The World Health Organization European Region was the main contributor to this global burden, followed by the WHO region of the Americas and the World Health Organization Western Pacific region. The global burden of trichinellosis is much lower than that of other foodborne parasitic diseases and is in sharp contrast to the high budget allocated to prevent the disease in many industrialised countries. To decrease the uncertainty around the current estimates, more knowledge is needed on the level of underreporting of clinical trichinellosis in different parts of the world.

Pre-clinical Evaluation of a New Antimicrobial Enzyme for the Control of Wound Bioburden.

 A new, optimized, antimicrobial enzyme system was developed for the control of wound bioburden. This Glucose oxidase-Lactoperoxidase-Guaiacol (GLG) system was analyzed for antimicrobial activity and cytotoxicity. The susceptibility of a wide range of antibiotic-resistant bacterial strains to the GLG-enzyme system was analyzed using minimum inhibitory concentration (MIC90), minimum bactericidal concentration (MBC) determination, and growth kinetics analysis. Additionally, challenge tests and cytotoxicity tests were performed with a new hydroactive alginate gel dressing with antimicrobial activity obtained by the presence of the GLG-enzyme system (Flaminal® Forte, Flen Pharma, Kontich, Belgium). All bacterial strains were susceptible to the GLG-enzyme system at low concentrations. The exact concentration required for growth arrest and cell death was dependent on the experimental design. Further, a 20% (w/v) GLG dilution showed no cytotoxicity toward fibroblasts and keratinocytes. Conversely, other antimicrobial wound-care products applied with the same dilution showed a high degree of cytotoxicity. With increasing concerns about bacterial resistance to antibiotics, this study shows that low concentrations of the GLG-enzyme system are successful in killing antibiotic-resistant bacterial strains. Furthermore, results show that GLG-enzyme system combines strong antimicrobial activity with non-cytotoxicity and promotes optimal wound healing.

Differential cell death programmes induced by silver dressings in vitro.

In past decades the gold standard for topical burn treatment was the use of silver sulfadiazine. Due to toxicity caused by the silver, the cream base itself, or a combination of both negatively influencing the wound healing process, the healthcare industry searched for alternatives. In recent years, various dressings containing silver have become available to wound professionals. Although these have been reported to be a significant improvement, the dressings still show residual cytotoxicity. Given the ongoing debate about whether and how these dressings influence cell survival, this article endeavours to clarify some of the mystique surrounding the subject. Various commercially available silver-type dressings were analysed in vitro and attention was paid to the cell death stage induced by these dressings on different cell lines. The results show that within 2 hours, for all dressings tested, cells undergo cell death and further analysis suggests that the death stage induced is dependent on the cell line and type of dressing investigated. Further, the antimicrobial activity of all dressings was analysed. The silver dressings tested have potent antimicrobial activity. Our results showed, however, that silver dressings induce rapid cell death of cells involved in wound healing. We therefore recommend the use of silver dressings only on critically contaminated wounds rather than use on a de facto basis.

Cytotoxicity of submicron emulsions and solid lipid nanoparticles for dermal application.

The cytotoxicity and physical properties of various submicron O/W emulsions and solid lipid nanoparticles for dermal applications were investigated. Droplet size and zetapotential of submicron emulsions depended on the composition of the cosurfactant blend used. The viability of J774 macrophages, mouse 3T3 fibroblasts and HaCaT keratinocytes was significantly reduced in the presence of stearylamine. Nanoparticles consisting of stearic acid or different kinds of adeps solidus could be manufactured when formulated with lecithin, sodium taurocholate, polysorbate 80 and stearylamine. Survival of macrophages was highly affected by stearic acid and stearylamine. In general a viability of more than 90% was observed when semi-synthetic glycerides or hard fat was employed to formulate nanoparticles.

Human antimicrobial peptides: defensins, cathelicidins and histatins.

Antimicrobial peptides, which have been isolated from many bacteria, fungi, plants, invertebrates and vertebrates, are an important component of the natural defenses of most living organisms. The isolated peptides are very heterogeneous in length, sequence and structure, but most of them are small, cationic and amphipathic. These peptides exhibit broad-spectrum activity against Gram-positive and Gram-negative bacteria, yeasts, fungi and enveloped viruses. A wide variety of human proteins and peptides also have antimicrobial activity and play important roles in innate immunity. In this review we discuss three important groups of human antimicrobial peptides. The defensins are cationic non-glycosylated peptides containing six cysteine residues that form three intramolecular disulfide bridges, resulting in a triple-stranded beta-sheet structure. In humans, two classes of defensins can be found: alpha-defensins and beta-defensins. The defensin-related HE2 isoforms will also be discussed. The second group is the family of histatins, which are small, cationic, histidine-rich peptides present in human saliva. Histatins adopt a random coil conformation in aqueous solvents and form alpha-helices in non-aqueous solvents. The third group comprises only one antimicrobial peptide, the cathelicidin LL-37. This peptide is derived proteolytically from the C-terminal end of the human CAP18 protein. Just like the histatins, it adopts a largely random coil conformation in a hydrophilic environment, and forms an alpha-helical structure in a hydrophobic environment.

Old yellow enzyme interferes with Bax-induced NADPH loss and lipid peroxidation in yeast.

The yeast transcriptional response to murine Bax expression was compared with the changes induced by H(2)O(2) treatment via microarray technology. Although most of the Bax-responsive genes were also triggered by H(2)O(2) treatment, OYE3, ICY2, MLS1 and BTN2 were validated to have a Bax-specific transcriptional response not shared with the oxidative stress trigger. In knockout experiments, only deletion of OYE3, coding for yeast Old yellow enzyme, attenuated the rate of Bax-induced growth arrest, cell death and NADPH decrease. Lipid peroxidation was completely absent in DeltaOYE3 expressing Bax. However, the absence of OYE3 sensitized yeast cells to H(2)O(2)-induced cell death, and increased the rate of NADPH decrease and lipid peroxidation. Our results clearly indicate that OYE3 interferes with Bax- and H(2)O(2)-induced lipid peroxidation and cell death in Saccharomyces cerevisiae.

Bax-induced cell death in Candida albicans.

Bax is a pro-apoptotic member of the Bcl-2 family of proteins involved in the regulation of genetically programmed cell death in mammalian cells. It has been shown that heterologous expression of Bax in several yeast species, such as Saccharomyces cerevisiae, Schizosaccharomyces pombe and Pichia pastoris, also induces cell death. In this study we investigated the effects of Bax expression in the pathogenic yeast Candida albicans. Cell death inducing expression of Bax required a synthetic BAX gene that was codon-optimized for expression in Candida albicans. Expression of this BAX gene resulted in growth inhibition and cell death. By fusing Bax with the yeast enhanced green fluorescent protein of Aequoria victoria, the cell death-inducing effect of Bax was increased due to reduced proteolytic degradation of Bax. Using this fusion protein we showed that, upon expression in C. albicans, Bax co-localizes with the mitochondria. Furthermore, we showed for the first time that expression of Bax in yeast causes the mitochondria, which are normally distributed throughout the cell, to cluster in the perinuclear region.

Role of oxidative phosphorylation in histatin 5-induced cell death in Saccharomyces cerevisiae.

The susceptibility of Saccharomyces cerevisiae to the anti-microbial peptide, histatin 5, was tested after pre-growth in fermentable and non-fermentable carbon sources and in the absence or presence of the uncoupler of oxidative phosphorylation, carbonyl cyanide m-chlorophenylhydrazone (CCCP). S. cerevisiae was more resistant to histatin 5 when grown on a fermentable carbon source compared to growth on a non-fermentable carbon source, indicating an important role for oxidative phosphorylation in histatin 5-induced cell death. Oxidative phosphorylation is a pre-requisite for histatin 5-induced cell death in Candida albicans but this is not the case in S. cerevisiae. Incubation of CCCP-treated S. cerevisiae cells with histatin 5 still resulted in cell death. These results suggest that histatin 5-induced cell death in S. cerevisiae differs from that in C. albicans.