A transcribed enhancer dictates mesendoderm specification in pluripotency.

Enhancers and long noncoding RNAs (lncRNAs) are key determinants of lineage specification during development. Here, we evaluate remodeling of the enhancer landscape and modulation of the lncRNA transcriptome during mesendoderm specification. We sort mesendodermal progenitors from differentiating embryonic stem cells (ESCs) according to Eomes expression, and find that enhancer usage is coordinated with mesendoderm-specific expression of key lineage-determining transcription factors. Many of these enhancers are associated with the expression of lncRNAs. Examination of ESC-specific enhancers interacting in three-dimensional space with mesendoderm-specifying transcription factor loci identifies MesEndoderm Transcriptional Enhancer Organizing Region (Meteor). Genetic and epigenetic manipulation of the Meteor enhancer reveal its indispensable role during mesendoderm specification and subsequent cardiogenic differentiation via transcription-independent and -dependent mechanisms. Interestingly, Meteor-deleted ESCs are epigenetically redirected towards neuroectodermal lineages. Loci, topologically associating a transcribed enhancer and its cognate protein coding gene, appear to represent therefore a class of genomic elements controlling developmental competence in pluripotency

The Swiss Pathogen Surveillance Platform - towards a nation-wide One Health data exchange platform for bacterial, viral and fungal genomics and associated metadata.

The Swiss Pathogen Surveillance Platform (SPSP) is a shared secure surveillance platform between human and veterinary medicine, to also include environmental and foodborne isolates. It enables rapid and detailed transmission monitoring and outbreak surveillance of pathogens using whole genome sequencing data and associated metadata. It features controlled data access, complex dynamic queries, dedicated dashboards and automated data sharing with international repositories, providing actionable results for public health and the vision to improve societal well-being and health

Neonatal intervention

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68335/2/10.1177_027112148300300105.pd

How much should we sequence? An analysis of the Swiss SARS-CoV-2 surveillance effort.

During the SARS-CoV-2 pandemic, many countries directed substantial resources toward genomic surveillance to detect and track viral variants. There is a debate over how much sequencing effort is necessary in national surveillance programs for SARS-CoV-2 and future pandemic threats. We aimed to investigate the effect of reduced sequencing on surveillance outcomes in a large genomic data set from Switzerland, comprising more than 143k sequences. We employed a uniform downsampling strategy using 100 iterations each to investigate the effects of fewer available sequences on the surveillance outcomes: (i) first detection of variants of concern (VOCs), (ii) speed of introduction of VOCs, (iii) diversity of lineages, (iv) first cluster detection of VOCs, (v) density of active clusters, and (vi) geographic spread of clusters. The impact of downsampling on VOC detection is disparate for the three VOC lineages, but many outcomes including introduction and cluster detection could be recapitulated even with only 35% of the original sequencing effort. The effect on the observed speed of introduction and first detection of clusters was more sensitive to reduced sequencing effort for some VOCs, in particular Omicron and Delta, respectively. A genomic surveillance program needs a balance between societal benefits and costs. While the overall national dynamics of the pandemic could be recapitulated by a reduced sequencing effort, the effect is strongly lineage-dependent-something that is unknown at the time of sequencing-and comes at the cost of accuracy, in particular for tracking the emergence of potential VOCs.IMPORTANCESwitzerland had one of the most comprehensive genomic surveillance systems during the COVID-19 pandemic. Such programs need to strike a balance between societal benefits and program costs. Our study aims to answer the question: How would surveillance outcomes have changed had we sequenced less? We find that some outcomes but also certain viral lineages are more affected than others by sequencing less. However, sequencing to around a third of the original effort still captured many important outcomes for the variants of concern such as their first detection but affected more strongly other measures like the detection of first transmission clusters for some lineages. Our work highlights the importance of setting predefined targets for a national genomic surveillance program based on which sequencing effort should be determined. Additionally, the use of a centralized surveillance platform facilitates aggregating data on a national level for rapid public health responses as well as post-analyses

SARS-CoV-2 N501Y Introductions and Transmissions in Switzerland from Beginning of October 2020 to February 2021-Implementation of Swiss-Wide Diagnostic Screening and Whole Genome Sequencing.

The rapid spread of the SARS-CoV-2 lineages B.1.1.7 (N501Y.V1) throughout the UK, B.1.351 (N501Y.V2) in South Africa, and P.1 (B.1.1.28.1; N501Y.V3) in Brazil has led to the definition of variants of concern (VoCs) and recommendations for lineage specific surveillance. In Switzerland, during the last weeks of December 2020, we established a nationwide screening protocol across multiple laboratories, focusing first on epidemiological and microbiological definitions. In January 2021, we validated and implemented an N501Y-specific PCR to rapidly screen for VoCs, which are then confirmed using amplicon sequencing or whole genome sequencing (WGS). A total of 13,387 VoCs have been identified since the detection of the first Swiss case in October 2020, with 4194 being B.1.1.7, 172 B.1.351, and 7 P.1. The remaining 9014 cases of VoCs have been described without further lineage specification. Overall, all diagnostic centers reported a rapid increase of the percentage of detected VOCs, with a range of 6 to 46% between 25 to 31 of January 2021 increasing towards 41 to 82% between 22 to 28 of February. A total of 739 N501Y positive genomes were analysed and show a broad range of introduction events to Switzerland. In this paper, we describe the nationwide coordination and implementation process across laboratories, public health institutions, and researchers, the first results of our N501Y-specific variant screening, and the phylogenetic analysis of all available WGS data in Switzerland, that together identified the early introduction events and subsequent community spreading of the VoCs

Efficacy assessment of a novel endolysin PlyAZ3aT for the treatment of ceftriaxone-resistant pneumococcal meningitis in an infant rat model.

Treatment failure in pneumococcal meningitis due to antibiotic resistance is an increasing clinical challenge and alternatives to antibiotics warrant investigation. Phage-derived endolysins efficiently kill gram-positive bacteria including multi-drug resistant strains, making them attractive therapeutic candidates. The current study assessed the therapeutic potential of the novel endolysin PlyAZ3aT in an infant rat model of ceftriaxone-resistant pneumococcal meningitis. Efficacy of PlyAZ3aT was assessed in a randomized, blinded and controlled experimental study in infant Wistar rats. Meningitis was induced by intracisternal infection with 5 x 107 CFU/ml of a ceftriaxone-resistant clinical strain of S. pneumoniae, serotype 19A. Seventeen hours post infection (hpi), animals were randomized into 3 treatment groups and received either (i) placebo (phosphate buffered saline [PBS], n = 8), (ii) 50 mg/kg vancomycin (n = 10) or (iii) 400 mg/kg PlyAZ3aT (n = 8) via intraperitoneal injection. Treatments were repeated after 12 h. Survival at 42 hpi was the primary outcome; bacterial loads in cerebrospinal fluid (CSF) and blood were secondary outcomes. Additionally, pharmacokinetics of PlyAZ3aT in serum and CSF was assessed. PlyAZ3aT did not improve survival compared to PBS, while survival for vancomycin treated animals was 70% which is a significant improvement when compared to PBS or PlyAZ3aT (p<0.05 each). PlyAZ3aT was not able to control the infection, reflected by the inability to reduce bacterial loads in the CSF, whereas Vancomycin sterilized the CSF and within 25 h. Pharmacokinetic studies indicated that PlyAZ3aT did not cross the blood brain barrier (BBB). In support, PlyAZ3aT showed a peak concentration of 785 μg/ml in serum 2 h after intraperitoneal injection but could not be detected in CSF. In experimental pneumococcal meningitis, PlyAZ3aT failed to cure the infection due to an inability to reach the CSF. Optimization of the galenic formulation e.g. using liposomes might enable crossing of the BBB and improve treatment efficacy

Isolation and characterization of bacteriophages from the human skin microbiome that infect Staphylococcus epidermidis.

Phage therapy might be a useful approach for the treatment of nosocomial infections; however, only few lytic phages suitable for this application are available for the opportunistic pathogen, Staphylococcus epidermidis. In the current study, we developed an efficient method to isolate bacteriophages present within the human skin microbiome, by using niche-specific S. epidermidis as the host for phage propagation. Staphylococcus epidermidis was identified on the forehead of 92% of human subjects tested. These isolates were then used to propagate phages present in the same skin sample. Plaques were observable on bacterial lawns in 46% of the cases where S. epidermidis was isolated. A total of eight phage genomes were genetically characterized, including the previously described phage 456. A total of six phage sequences were unique, and spanned each of the major staphylococcal phage families; Siphoviridae (n = 3), Podoviridae (n = 1) and Myoviridae (n = 2). One of the myoviruses (vB_SepM_BE06) was identified on the skin of three different humans. Comparative analysis identified novel genes including a putative N-acetylmuramoyl-L-alanine amidase gene. The host-range of each unique phage was characterized using a panel of diverse staphylococcal strains (n = 78). None of the newly isolated phages infected more than 52% of the S. epidermidis strains tested (n = 44), and non-S. epidermidis strains where rarely infected, highlighting the narrow host-range of the phages. One of the phages (vB_SepM_BE04) was capable of killing staphylococcal cells within biofilms formed on polyurethane catheters. Uncovering a richer diversity of available phages will likely improve our understanding of S. epidermidis-phage interactions, which will be important for future therapy

Benefits of Aerosolized Phages for the Treatment of Pneumonia Due to Methicillin-Resistant Staphylococcus aureus: An Experimental Study in Rats.

The optimal method for delivering phages in the context of ventilator-associated pneumonia (VAP) is unknown. In the current study, we assessed the utility of aerosolized phages (aerophages) for experimental methicillin-resistant Staphylococcus aureus (MRSA) pneumonia. Rats were ventilated for 4 hours before induction of pneumonia. Animals received one of the following: (1) aerophages; (2) intravenous (IV) phages; (3) a combination of IV and aerophages; (4) IV linezolid; or (5) a combination of IV linezolid and aerophages. Phages were administered at 2, 12, 24, 48, and 72 hours, and linezolid was administered at 2, 12, 24, 36, 48, 60, and 72 hours. The primary outcome was survival at 96 hours. Secondary outcomes were bacterial and phage counts in tissues and histopathological scoring of the lungs. Aerophages and IV phages each rescued 50% of animals from severe MRSA pneumonia (P < .01 compared with placebo controls). The combination of aerophages and IV phages rescued 91% of animals, which was higher than either monotherapy (P < .05). Standard-of-care antibiotic linezolid rescued 38% of animals. However, linezolid and aerophages did not synergize in this setting (55% survival). Aerosolized phage therapy showed potential for the treatment of MRSA pneumonia in an experimental animal model and warrants further investigation for application in humans

Bacteriophages Improve Outcomes in Experimental Staphylococcus aureus Ventilator-associated Pneumonia.

Rationale: Infections caused by multidrug-resistant bacteria are a major clinical challenge. Phage therapy is a promising alternative antibacterial strategy.Objectives: To evaluate the efficacy of intravenous phage therapy for the treatment of ventilator-associated pneumonia due to methicillin-resistant Staphylococcus aureus in rats.Methods: In a randomized, blinded, controlled experimental study, we compared intravenous teicoplanin (3 mg/kg, n = 12), a cocktail of four phages (2-3 × 10 <sup>9</sup> plaque-forming units/ml of 2003, 2002, 3A, and K; n = 12), and a combination of both (n = 11) given 2, 12, and 24 hours after induction of pneumonia, and then once daily for 4 days. The primary outcome was survival at Day 4. Secondary outcomes were bacterial and phage densities in lungs and spleen, histopathological scoring of infection within the lungs, and inflammatory biomarkers in blood.Measurements and Main Results: Treatment with either phages or teicoplanin increased survival from 0% to 58% and 50%, respectively (P < 0.005). The combination of phages and antibiotics did not further improve outcomes (45% survival). Animal survival correlated with reduced bacterial burdens in the lung (1.2 × 10 <sup>6</sup> cfu/g of tissue for survivors vs. 1.2 × 10 <sup>9</sup> cfu/g for nonsurviving animals; P < 0.0001), as well as improved histopathological outcomes. Phage multiplication within the lung occurred during treatment. IL-1β increased in all treatment groups over the course of therapy.Conclusions: Phage therapy was as effective as teicoplanin in improving survival and decreasing bacterial load within the lungs of rats infected with methicillin-resistant S. aureus. Combining antibiotics with phage therapy did not further improve outcomes