Antithrombotic therapy after heart valve surgery: contemporary practice in the UK.

Objectives: There is a lack of high-quality data informing the optimal antithrombotic drug strategy following bioprosthetic heart valve replacement or valve repair. Disparity in recommendations from international guidelines reflects this. This study aimed to document current patterns of antithrombotic prescribing after heart valve surgery in the UK.

Navigating the infodemic: A qualitative study of university students' information strategies during the COVID-19 pandemic.

Objectives: We aimed to study the strategies which university students developed for vetting information during the COVID-19 pandemic and associated infodemic.

Methods: We conducted semi-structured interviews with 34 students, using a piloted topic guide which explored several areas of pandemic experiences, including students' use of media. Transcripts were analysed inductively following the thematic approach.

Novel method for prediction of combinatorial phase-variable gene expression states.

Short sequence repeat mediated phase variation results in diverse phenotype presentation in many bacteria including and species. Current methods for identifying the expression states of phase-variable genes involve taking a high number of single colonies. This approach is subject to bias, sampling effects and high workloads that reduce the ability to perform intermediary sampling.

Development of a robust and quantitative high-throughput screening method for assessing phenotypic variation in large isolate collections.

Genome-wide association studies are a powerful approach for identifying determinants of disease. For infectious diseases, high throughput assays are required for measuring the variance in multiple virulence-related phenotypes of large bacterial isolate collections and for association of this phenotypic variance with genotype. The primary limiting factors are cost, effectiveness and a standardized inoculum.

Variable disruption of epithelial monolayers by carriage isolates of the hypervirulent MenW cc11 and MenY cc23 lineages.

Colonization of mucosal tissues by requires adhesion mediated by the type IV pilus and multiple outer-membrane proteins. Penetration of the mucosa and invasion of epithelial cells are thought to contribute to host persistence and invasive disease. Using Calu-3 cell monolayers grown at an air-liquid interface, we examined adhesion, invasion and monolayer disruption by carriage isolates of two clonal complexes of .

Cross-Sectional Study of University Students' Attitudes to 'On Campus' Delivery of COVID-19, MenACWY and MMR Vaccines and Future-Proofing Vaccine Roll-Out Strategies.

University students are a critical group for vaccination programmes against COVID-19, meningococcal disease (MenACWY) and measles, mumps and rubella (MMR). We aimed to evaluate risk factors for vaccine hesitancy and views about on-campus vaccine delivery among university students. Data were obtained through a cross-sectional anonymous online questionnaire study of undergraduate students in June 2021 and analysed by univariate and multivariate tests to detect associations.

University Students' Mental Health and Well-Being during the COVID-19 Pandemic: Findings from the UniCoVac Qualitative Study.

The worldwide spread of the coronavirus disease 2019 (COVID-19) pandemic in early 2020 affected all major sectors, including higher education. The measures to contain the spread of this deadly disease led to the closure of colleges and universities across the globe, disrupting the lives of millions of students and subjecting them to a new world of online learning. These sudden disturbances coupled with the demands of a new learning system and the experiences of living through a pandemic have placed additional strains on the mental health of university students.

Phase Variation During Host Colonization and Invasion by and Other Species.

Phase variation (PV) is a phenomenon common to a variety of bacterial species for niche adaption and survival in challenging environments. Among species, PV depends on the presence of intergenic and intragenic hypermutable G/C homopolymeric tracts. The presence of phase-variable genes is of especial interest for species that cause foodborne or zoonotic infections in humans.

How does feedback from phage infections influence the evolution of phase variation in Campylobacter?

Campylobacter jejuni (C. jejuni) causes gastroenteritis following the consumption of contaminated poultry meat, resulting in a large health and economic burden worldwide. Phage therapy is a promising technique for eradicating C.

Rapid Transmission of a Hyper-Virulent Meningococcal Clone Due to High Effective Contact Numbers and Super Spreaders.

Rapid transmission, a critical contributory factor in outbreaks of invasive meningococcal disease, requires naïve populations of sufficient size and intermingling. We examined genomic variability and transmission dynamics in a student population subject to an 11-fold increase in carriage of a hypervirulent serogroup W ST-11 clone. Phylogenetic clusters, mutation and recombination rates were derived by bioinformatic analyses of whole-genome sequencing data.

Does Blood Transfusion Have an Effect on Outcomes After Aortic Valve Replacement Surgery?

Objective: Long-term outcomes following surgical aortic valve replacement (AVR) are excellent. However, there is a significant early morbidity burden. Red cell transfusion is common in the perioperative period and deleterious effects of receiving a transfusion on early postoperative morbidity are well described in observational studies.

Broad vaccine protection against Neisseria meningitidis using factor H binding protein.

Neisseria meningitidis, the causative agent of invasive meningococcal disease (IMD), is classified into different serogroups defined by their polysaccharide capsules. Meningococcal serogroups A, B, C, W, and Y are responsible for most IMD cases, with serogroup B (MenB) causing a substantial percentage of IMD cases in many regions. Vaccines using capsular polysaccharides conjugated to carrier proteins have been successfully developed for serogroups A, C, W, and Y.

Meningococcal core and accessory phasomes vary by clonal complex.

is a Gram-negative human commensal pathogen, with extensive phenotypic plasticity afforded by phase-variable (PV) gene expression. Phase variation is a stochastic switch in gene expression from an ON to an OFF state, mediated by localized hypermutation of simple sequence repeats (SSRs). Circulating clones vary in propensity to cause disease, with some clonal complexes (ccs) classified as hypervirulent and others as carriage-associated.

Localized Hypermutation is the Major Driver of Meningococcal Genetic Variability during Persistent Asymptomatic Carriage.

Host persistence of bacteria is facilitated by mutational and recombinatorial processes that counteract loss of genetic variation during transmission and selection from evolving host responses. Genetic variation was investigated during persistent asymptomatic carriage of Interrogation of whole-genome sequences for paired isolates from 25 carriers showed that mutations were infrequent, while horizontal gene transfer occurred in 16% of carriers. Examination of multiple isolates per time point enabled separation of sporadic and transient allelic variation from directional variation.

Selective and non-selective bottlenecks as drivers of the evolution of hypermutable bacterial loci.

Bottlenecks reduce the size of the gene pool within populations of all life forms with implications for their subsequent survival. Here, we examine the effects of bottlenecks on bacterial commensal-pathogens during transmission between, and dissemination within, hosts. By reducing genetic diversity, bottlenecks may alter individual or population-wide adaptive potential.

Corrigendum: Variant Signal Peptides of Vaccine Antigen, FHbp, Impair Processing Affecting Surface Localization and Antibody-Mediated Killing in Most Meningococcal Isolates.

[This corrects the article DOI: 10.3389/fmicb.2019.

Variant Signal Peptides of Vaccine Antigen, FHbp, Impair Processing Affecting Surface Localization and Antibody-Mediated Killing in Most Meningococcal Isolates.

Meningococcal lipoprotein, Factor H binding protein (FHbp), is the sole antigen of the Trumenba vaccine (Pfizer) and one of four antigens of the Bexsero vaccine (GSK) targeting serogroup B isolates. Lipidation of FHbp is assumed to occur for all isolates. We show in the majority of a collection of United Kingdom isolates (1742/1895) non-synonymous single nucleotide polymorphisms (SNPs) in the signal peptide (SP) of FHbp.

Gastro-duodenal disease in Africa: Literature review and clinical data from Accra, Ghana.

Gastroduodenal disease (GDD) was initially thought to be uncommon in Africa. Amongst others, lack of access to optimal health infrastructure and suspicion of conventional medicine resulted in the reported prevalence of GDD being significantly lower than that in other areas of the world. Following the increasing availability of flexible upper gastro-intestinal endoscopy, it has now become apparent that GDD, especially peptic ulcer disease (PUD), is prevalent across the continent of Africa.

Phage-Resistant Phase-Variant Sub-populations Mediate Herd Immunity Against Bacteriophage Invasion of Bacterial Meta-Populations.

Hypermutable loci are widespread in bacteria as mechanisms for rapid generation of phenotypic diversity within a population that enables survival of fluctuating, often antagonistic, selection pressures. Localized hypermutation can mediate phase variation and enable survival of bacteriophage predation due to high frequency, reversible alterations in the expression of phage receptors. As phase variation can also generate population-to-population heterogeneity, we hypothesized that this phenomenon may facilitate survival of spatially-separated bacterial populations from phage invasion in a manner analogous to herd immunity to infectious diseases in human populations.

Potentiation of Phase Variation in Multiple Outer-Membrane Proteins During Spread of the Hyperinvasive Neisseria meningitidis Serogroup W ST-11 Lineage.

Background: Since 2009, increases in the incidence of invasive meningococcal disease have occurred in the United Kingdom due to a sublineage of the Neisseria meningitidis serogroup W ST-11 clonal complex (hereafter, the "original UK strain"). In 2013, a descendent substrain (hereafter, the "2013 strain") became the dominant disease-causing variant. Multiple outer-membrane proteins of meningococci are subject to phase-variable switches in expression due to hypermutable simple-sequence repeats.

Assessment of fHbp Expression Level by Reverse Transcriptase Quantitative PCR and Promoter Sequence Analysis.

Reverse transcriptase quantitative PCR (RT qPCR) is widely used for assessing the levels of expression of specific genes in various organisms. Here we describe a RT qPCR assay designed to determine the level of expression of fHbp in multiple isolates of Neisseria meningitidis. The level of expression is measured by a two-step qPCR and is associated with a promoter region analysis.

Determination of Repeat Number and Expression States of Phase-Variable Loci Through Next Generation Sequencing and Bioinformatic Analysis.

Phase variation (PV) enables high frequency, reversible switches in expression of genetic loci across numerous species of bacteria. A major mechanism of PV in bacteria is the use of slipped strand mispairing across simple sequence repeats (SSRs). The generation and online availability of genomic datasets enables a comprehensive analysis of the distribution and composition of SSRs across multiple bacterial genomes of a species.

PhasomeIt: an 'omics' approach to cataloguing the potential breadth of phase variation in the genus Campylobacter.

Hypermutable simple sequence repeats (SSRs) are drivers of phase variation (PV) whose stochastic, high-frequency, reversible switches in gene expression are a common feature of several pathogenic bacterial species, including the human pathogen Campylobacter jejuni. Here we examine the distribution and conservation of known and putative SSR-driven phase variable genes - the phasome - in the genus Campylobacter. PhasomeIt, a new program, was specifically designed for rapid identification of SSR-mediated PV.

Phase Variation of NadA in Invasive Neisseria meningitidis Isolates Impacts on Coverage Estimates for 4C-MenB, a MenB Vaccine.

A recombinant NadA protein is one of the four major protective antigens of 4C-MenB (Bexsero), a vaccine developed for serogroup B (MenB). The meningococcal antigen typing system (MATS) is utilized as a high-throughput assay for assessing the invasive MenB strain coverage of 4C-MenB. Where present, the gene is subject to phase-variable changes in transcription due to a 5'TAAA repeat tract located in a regulatory region.