Blood transcriptomic discrimination of bacterial and viral infections in the emergency department: a multi-cohort observational validation study.

Background: There is an urgent need to develop biomarkers that stratify risk of bacterial infection in order to support antimicrobial stewardship in emergency hospital admissions.

Methods: We used computational machine learning to derive a rule-out blood transcriptomic signature of bacterial infection (SeptiCyte™ TRIAGE) from eight published case-control studies. We then validated this signature by itself in independent case-control data from more than 1500 samples in total, and in combination with our previously published signature for viral infections (SeptiCyte™ VIRUS) using pooled data from a further 1088 samples.

Stunted microbiota and opportunistic pathogen colonization in caesarean-section birth.

Immediately after birth, newborn babies experience rapid colonization by microorganisms from their mothers and the surrounding environment. Diseases in childhood and later in life are potentially mediated by the perturbation of the colonization of the infant gut microbiota. However, the effects of delivery via caesarean section on the earliest stages of the acquisition and development of the gut microbiota, during the neonatal period (≤1 month), remain controversial.

Getting the balance right-tackling the obesogenic environment by reducing unhealthy options in a hospital shop without affecting profit.

Background: UK hospitals have been criticized for fuelling obesity by allowing contracts with food retailers selling high fat and high-sugar products on hospital premises.

Methods: We assessed the impact for a major retailer of increasing healthy food choices at their Royal Free London NHS Foundation Trust outlet. To assess the impact on sales, profit and acceptability to customers, a multi-component intervention based on behavioural insights theory was enacted over 2 months (November-December 2014) at the Royal Free site WHSmith.

Strength of Neisseria meningitidis binding to endothelial cells requires highly-ordered CD147/β-adrenoceptor clusters assembled by alpha-actinin-4.

Neisseria meningitidis (meningococcus) is an invasive bacterial pathogen that colonizes human vessels, causing thrombotic lesions and meningitis. Establishment of tight interactions with endothelial cells is crucial for meningococci to resist haemodynamic forces. Two endothelial receptors, CD147 and the β2-adrenergic receptor (βAR), are sequentially engaged by meningococci to adhere and promote signalling events leading to vascular colonization, but their spatiotemporal coordination is unknown.

Blood transcriptomic diagnosis of pulmonary and extrapulmonary tuberculosis.

Novel rapid diagnostics for active tuberculosis (TB) are required to overcome the time delays and inadequate sensitivity of current microbiological tests that are critically dependent on sampling the site of disease. Multiparametric blood transcriptomic signatures of TB have been described as potential diagnostic tests. We sought to identify the best transcript candidates as host biomarkers for active TB, extend the evaluation of their specificity by comparison with other infectious diseases, and to test their performance in both pulmonary and extrapulmonary TB.

Transcriptional Profiling of Endobronchial Ultrasound-Guided Lymph Node Samples Aids Diagnosis of Mediastinal Lymphadenopathy.

Background: Endobronchial ultrasound (EBUS)-guided biopsy is the mainstay for investigation of mediastinal lymphadenopathy for laboratory diagnosis of malignancy, sarcoidosis, or TB. However, improved methods for discriminating between TB and sarcoidosis and excluding malignancy are still needed. We sought to evaluate the role of genomewide transcriptional profiling to aid diagnostic processes in this setting.

Pathogenic Neisseria meningitidis utilizes CD147 for vascular colonization.

Neisseria meningitidis is a cause of meningitis epidemics worldwide and of rapidly progressing fatal septic shock. A crucial step in the pathogenesis of invasive meningococcal infections is the adhesion of bloodborne meningococci to both peripheral and brain endothelia, leading to major vascular dysfunction. Initial adhesion of pathogenic strains to endothelial cells relies on meningococcal type IV pili, but the endothelial receptor for bacterial adhesion remains unknown.

The immune system as a biomonitor: explorations in innate and adaptive immunity.

The human immune system has a highly complex, multi-layered structure which has evolved to detect and respond to changes in the internal microenvironment of the body. Recognition occurs at the molecular or submolecular scale, via classical reversible receptor-ligand interactions, and can lead to a response with great sensitivity and speed. Remarkably, recognition is coupled to memory, such that responses are modulated by events which occurred years or even decades before.

Binding to Na(+) /H(+) exchanger regulatory factor 2 (NHERF2) affects trafficking and function of the enteropathogenic Escherichia coli type III secretion system effectors Map, EspI and NleH.

Enteropathogenic Escherichia coli (EPEC) strains are diarrhoeal pathogens that use a type III secretion system to translocate effector proteins into host cells in order to colonize and multiply in the human gut. Map, EspI and NleH1 are conserved EPEC effectors that possess a C-terminal class I PSD-95/Disc Large/ZO-1 (PDZ)-binding motif. Using a PDZ array screen we identified Na(+)/H(+) exchanger regulatory factor 2 (NHERF2), a scaffold protein involved in tethering and recycling ion channels in polarized epithelia that contains two PDZ domains, as a common target of Map, EspI and NleH1.

Tracking the secretion of fluorescently labeled type III effectors from single bacteria in real time.

A large number of Gram negative pathogens use a specialized needle-like molecular machine known as Type III Secretion (T3S) system. This highly sophisticated molecular device consists of a basal body spanning the two bacterial membranes and a protruding needle structure that is connected to a distal translocator complex. The main features of the T3S system are (i) activation after host cellular membrane contact and (ii) the ability to "inject" effectors into host cells through the needle apparatus across three membranous structures--two bacterial and one host cellular--without effector leakage into the exterior space.

The enteropathogenic Escherichia coli type III secretion system effector Map binds EBP50/NHERF1: implication for cell signalling and diarrhoea.

Enteropathogenic Escherichia coli (EPEC) is the single most important contributor to child diarrhoea in developing countries. Nevertheless, the mechanism responsible for EPEC diarrhoea remains elusive. Using the yeast two-hybrid system to determine the target host cell protein of the EPEC type III secretion system effector Map led to identification of ezrin/radixin/moesin (ERM)-binding phosphoprotein 50 (EBP50), also known as Na+/H+ exchanger regulatory factor 1 (NHERF1).

Subversion of actin dynamics by EPEC and EHEC.

During the course of infection, enteropathogenic and enterohaemorrhagic Escherichia coli (EPEC and EHEC, respectively) subvert the host cell signalling machinery and hijack the actin cytoskeleton to tighten their interaction with the gut epithelium, while avoiding phagocytosis by professional phagocytes. Much progress has been made recently in our understanding of how EPEC and EHEC regulate the pathways leading to local activation of two regulators of actin cytoskeleton dynamics, the Wiskott-Aldrich syndrome protein (N-WASP) and the Arp2/3 complex. A recent highlight is the unravelling of functions for effector proteins (particularly Tir, TccP, Map and EspG/EspG2) that are injected into the host cell by a type III secretion system.

Identification of a novel Citrobacter rodentium type III secreted protein, EspI, and roles of this and other secreted proteins in infection.

Citrobacter rodentium is a member of a group of pathogens that colonize the lumen of the host gastrointestinal tract via attaching and effacing (A/E) lesion formation. C. rodentium, which causes transmissible colonic hyperplasia in mice, is used as an in vivo model system for the clinically significant A/E pathogens enterohemorrhagic and enteropathogenic Escherichia coli.

Rac regulates endothelial morphogenesis and capillary assembly.

Endothelial cells undergo branching morphogenesis to form capillary tubes. We have utilized an in vitro Matrigel overlay assay to analyze the role of the cytoskeleton and Rho GTPases during this process. The addition of matrix first induces changes in cell morphology characterized by the formation of dynamic cellular protrusions and the assembly of discrete aggregates or cords of aligned cells resembling primitive capillary-like structures, but without a recognizable lumen.