Silica nanoparticles with encapsulated DNA (SPED) to trace the spread of pathogens in healthcare.

BACKGROUND To establish effective infection control protocols, understanding pathogen transmission pathways is essential. Non-infectious surrogate tracers may safely explore these pathways and challenge pre-existing assumptions. We used silica nanoparticles with encapsulated DNA (SPED) for the first time in a real-life hospital setting to investigate potential transmission routes of vancomycin-resistant enterococci in the context of a prolonged outbreak. METHODS The two study experiments took place in the 900-bed University Hospital Zurich, Switzerland. A three-run 'Patient experiment' investigated pathogen transmission via toilet seats in a two-patient room with shared bathroom. First, various predetermined body and fomite sites in a two-bed patient room were probed at baseline. Then, after the first patient was contaminated with SPED at the subgluteal region, both patients sequentially performed a toilet routine. All sites were consequently swabbed again for SPED contamination. Eight hours later, further spread was tested at predefined sites in the patient room and throughout the ward. A two-run 'Mobile device experiment' explored the potential transmission by mobile phones and stethoscopes in a quasi-realistic setting. All SPED contamination statuses and levels were determined by real-time qPCR. RESULTS Over all three runs, the 'Patient experiment' yielded SPED in 59 of 73 (80.8%) predefined body and environmental sites. Specifically, positivity rates were 100% on subgluteal skin, toilet seats, tap handles, and entertainment devices, the initially contaminated patients' hands; 83.3% on patient phones and bed controls; 80% on intravenous pumps; 75% on toilet flush plates and door handles, and 0% on the initially not contaminated patients' hands. SPED spread as far as doctor's keyboards (66.6%), staff mobile phones (33.3%) and nurses' keyboards (33.3%) after eight hours. The 'Mobile device experiment' resulted in 16 of 22 (72.7%) positive follow-up samples, and transmission to the second patient occurred in one of the two runs. CONCLUSIONS For the first time SPED were used to investigate potential transmission pathways in a real hospital setting. The results suggest that, in the absence of targeted cleaning, toilet seats and mobile devices may result in widespread transmission of pathogens departing from one contaminated patient skin region

Auf dem Weg zur individualisierten Medizin - Grid-basierte Services für die EPA der Zukunft.

Personalized Medicine is of paramount interest for many areas in Medical Informatics. Therefore genotype data as well a phenotype data about patients have to be available. This data will be stored in Electronic Health Records or – patient controlled - in Personal Health Records. As the amount of (raw) data is rising continuously, methods for a secure data administration have to be found. Grid Services offer data storage, can support data retrieval and the presentation of the data. The basic security services could be provided by the German health professional infrastructure, but there are many security challenges to be faced

Two cases of long-lasting, sub-microscopic Plasmodium malariae infections in adults from coastal Tanzania

Malaria is endemic in Tanzania with majority of clinical cases caused by Plasmodium falciparum. Additionally, Plasmodium malariae and Plasmodium ovale spp. are also present and clinical manifestations caused by these infections are not well described. Clinical episodes caused by P. malariae infections are often characterized by a relatively mild illness with a low number of parasites, which can persist for long periods. In this report, two cases of P. malariae infections that were identified during a clinical trial evaluating the P. falciparum malaria vaccine candidate, PfSPZ Vaccine are described. The two participants were followed up and monitored for clinical and laboratory parameters to assess vaccine safety providing the opportunity to study clinical manifestations of P. malariae over 4 months.; Two young, healthy Tanzanian men infected with low density asexual blood stage P. malariae diagnosed by quantitative polymerase chain reaction (qPCR) are described. Retrospective analysis of collected and stored blood samples revealed that the two volunteers had constant asexual blood stage parasitaemia for more than 4 months. During the 132 days of infection, the volunteers' vital signs, body temperature and serum biochemistry all remained within normal ranges. Haematological abnormalities, which were transiently outside normal ranges, were regarded as not clinically significant. During this time period, four consecutive evaluations of blood samples by thick blood smear microscopy conducted by an experienced microscopist were all negative, indicating the presence of low-density sub-microscopic infections.; The two cases of P. malariae infections presented here confirm the ability of this Plasmodium species to persist at low density in the human host for extended time periods without causing clinical symptoms. The presented data also demonstrate that clinical study sites in malaria endemic regions need to have a strong malaria diagnostic infrastructure, including the ability of capturing sub-microscopic parasitaemia and differentiation of Plasmodium species. Trial registration ClinicalTrials.gov: NCT02613520, https://clinicaltrials.gov/ct2/show/NCT02613520 , Registered: November 24th 2015, Enrolment of the first participant to the trial: December 15th 2015, Trial was registered before the first participant was enrolled

TSPO acts as an immune resistance gene involved in the T cell mediated immune control of glioblastoma

Glioblastoma (GB) IDH-wildtype is the most malignant primary brain tumor. It is particularly resistant to current immunotherapies. Translocator protein 18 kDa (TSPO) is upregulated in GB and correlates with malignancy and poor prognosis, but also with increased immune infiltration. Here, we studied the role of TSPO in the regulation of immune resistance of human GB cells. The role of TSPO in tumor immune resistance was experimentally determined in primary brain tumor initiating cells (BTICs) and cell lines through genetic manipulation of TSPO expression and subsequent cocultures with antigen specific cytotoxic T cells and autologous tumor-infiltrating T cells. Death inducing intrinsic and extrinsic apoptotic pathways affected by TSPO were investigated. TSPO-regulated genes mediating apoptosis resistance in BTICs were identified through gene expression analysis and subsequent functional analyses. TSPO transcription in primary GB cells correlated with CD8+ T cell infiltration, cytotoxic activity of T cell infiltrate, expression of TNFR and IFNGR and with the activity of their downstream signalling pathways, as well as with the expression of TRAIL receptors. Coculture of BTICs with tumor reactive cytotoxic T cells or with T cell-derived factors induced TSPO up-regulation through T cell derived TNFα and IFNγ. Silencing of TSPO sensitized BTICs against T cell-mediated cytotoxicity. TSPO selectively protected BTICs against TRAIL-induced apoptosis by regulating apoptosis pathways. TSPO also regulated the expression of multiple genes associated with resistance against apoptosis. We conclude that TSPO expression in GB is induced through T cell-derived cytokines TNFα and IFNγ and that TSPO expression protects GB cells against cytotoxic T cell attack through TRAIL. Our data thereby provide an indication that therapeutic targeting of TSPO may be a suitable approach to sensitize GB to immune cell-mediated cytotoxicity by circumventing tumor intrinsic TRAIL resistance

Screaming 'Black' Murder: Crime Fiction and the Construction of Ethnic Identities

A significant segment of crime fiction is concerned with the representation of ethnic identities and may to some extent be considered paradigmatic of the participation of literary texts in discourses on race and minorities. This article explores constructions of ethnic identities in American, British, and South African crime fiction from the 1920s to the early twenty-first century. In particular, the focus will be on such texts in which the ethno-cultural identity of the detective gives special prominence not only to the ethnic particularity of the fictional character itself and of its environs but frequently also to that of its author. Main texts discussed are Rudolph Fisher’s The Conjure Man Dies (1932), Earl Derr Biggers’ The House Without a Key (1925) and The Black Camel (1929), Walter Mosley’s Devil in a Blue Dress (1990) and Little Scarlet (2004) as well as James McClure’s The Gooseberry Fool (1974) and Patrick Neate’s City of Tiny Lights (2005). It is argued that all of these texts have a distinct subversive potential of which the construction of ethnic identities becomes the main vehicle because these identities are the products and the catalysts of the conflicts negotiated in ethnic crime fiction and correlating to ‘reality’

Drivers of immune resistance in MITFlow melanomas

Immunotherapy with immune checkpoint inhibitors has largely improved survival of melanoma patients. However, many patients still do not benefit from so far developed strategies due to primary or acquired resistance. In malignant melanoma, increased immune resistance is associated with the downregulation of Microphtalmia-associated transcription factor (MITF). MITF is a key regulator of melanocyte proliferation and survival. In melanoma cells its decrease results in a dedifferentiated phenotype which is concomitant with invasiveness and therapy resistance. The aim of this work was to identify mechanisms of immune resistance in MITFlow human melanoma cells. In order to discover genes that confer immune resistance in MITFlow melanomas, I performed a functional high-throughput (HTP) RNAi screen targeting 5202 genes in two melanoma cell lines derived from one immunotherapy refractory melanoma patient. One of these cell lines, Ma-Mel-86a expressed low levels of MITF while the other, Ma-Mel-86c expressed high MITF levels. The use of both cell lines allowed for the discrimination of common and differential effects of the genes in the MITFlow and MITFhigh melanoma cell lines. 91 genes that caused a tumor cell intrinsic resistance against the attack by cytotoxic T cells were identified by this screen and confirmed in secondary validation experiments. The in vitro work was paralleled by extensive bioinformatic analyses using public bulk and single cell RNA-Seq data sets of melanoma samples or patient-derived melanoma cell lines. Immune resistance (IR) genes were shown to be co-expressed in gene expression clusters. IR genes and gene clusters showed heterogeneous expression patterns between patients but homogeneous expression within individual patients and certain genes and clusters could be correlated to a low MITF expression. Furthermore, IR genes were differentially expressed between melanoma cells and healthy cells within the melanoma stroma, and between MITFlow and MITFhigh melanoma cells. Interestingly, MITFlow cells still shared features with MITFhigh cells, but additionally with immunosuppressive cancer-associated fibroblasts. Several IR genes (TMCC3, SLC39A13, MOK and ZNF443) with a particular strong immune resistance potential that were mostly differentially expressed in MITFlow melanomas were selected for further functional assessment. These analyses revealed a protective role of these genes against apoptosis induction through stimulation by T cell derived cytotoxic ligands such as TRAIL, TNFα or IFNγ. I performed extensive mode of action analyses for two IR genes, Transmembrane and coiled-coil domain family 3 (TMCC3) and Solute carrier family 39 member 13 (SLC39A13) to uncover their mechanisms to convey resistance in the MITFlow cell line Ma-Mel-86a. TMCC3 which is located in the membrane of the endoplasmic reticulum (ER) protects MITFlow melanoma cells against ER stress and ensures apoptosis resistance by increasing the expression of anti-apoptotic molecules, especially of those involved in death receptor signaling such as CFLAR and BCL-2. Upon treatment with death receptor ligand TRAIL to which Ma-Mel-86a showed primary resistance, apoptosis is executed in TMCC3 deficient cells. SLC39A13/ZIP13 is a zinc transporter located in the Golgi apparatus that protects MITFlow cells against IFNγ-mediated apoptosis. SLC39A13/ZIP13 controls STAT1 and IFNγR1 expression and induces the expression of anti-apoptotic BCL-2, making the cells resistant against IFNγ-mediated lysis. In conclusion, I identified a variety of so far unknown immune resistance genes in immunotherapy refractory MITFlow melanoma cells that regulate T cell and cytotoxic ligand-mediated rejection which may represent novel targets for future immunotherapeutic interventions in malignant melanoma

Silica nanoparticles with encapsulated DNA (SPED) - a novel surrogate tracer for microbial transmission in healthcare

BACKGROUND: The increase in antimicrobial resistance is of worldwide concern. Surrogate tracers attempt to simulate microbial transmission by avoiding the infectious risks associated with live organisms. We evaluated silica nanoparticles with encapsulated DNA (SPED) as a new promising surrogate tracer in healthcare. METHODS: SPED and Escherichia coli were used to implement three experiments in simulation rooms and a microbiology laboratory in 2017-2018. Experiment 1 investigated the transmission behaviour of SPED in a predefined simulated patient-care scenario. SPED marked with 3 different DNA sequences (SPED1-SPED3) were introduced at 3 different points of the consecutive 13 touch sites of a patient-care scenario that was repeated 3 times, resulting in a total of 288 values. Experiment 2 evaluated SPED behaviour following hand cleaning with water and soap and alcohol-based handrub. Experiment 3 compared transfer dynamics of SPED versus E. coli in a laboratory using a gloved finger touching two consecutive sites on a laminate surface after a first purposefully contaminated site. RESULTS: Experiment 1: SPED adhesiveness on bare skin after a hand-to-surface exposure was high, leading to a dissemination of SPED1-3 on all consecutive surface materials with a trend of decreasing recovery rates, also reflecting touching patterns in concordance with contaminated fingers versus palms. Experiment 2: Hand washing with soap and water resulted in a SPED reduction of 96%, whereas hand disinfection led to dispersal of SPED from the palm to the back of the hand. Experiment 3: SPED and E. coli concentration decreased in parallel with each transmission step - with SPED showing a trend for less reduction and variability. CONCLUSIONS: SPED represent a convenient and safe instrument to simulate pathogen spread by contact transmission simultaneously from an infinite number of sites. They can be further developed as a central asset for successful infection prevention in healthcare

Toward a More Balanced View of Non-Native Species

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