Short-sighted evolution of virulence for invasive gut microbes: From hypothesis to tests.

Why microbes harm their hosts is a fundamental question in evolutionary biology with broad relevance to our understanding of infectious diseases. Several hypotheses have been proposed to explain this "evolution of virulence." In this perspective, we reexamine one of these hypotheses in the specific context of the human gut microbiome, namely short-sighted evolution.

Collateral Damage in the Human Gut Microbiome - Is Significantly Less Prevalent in an Antibiotic-Treated Adult Population Compared to Non-Antibiotic Treated Controls.

Antibiotics can drive the rapid loss of non-target, phylogenetically diverse microorganisms that inhabit the human gut. This so-called "collateral damage" has myriad consequences for host health and antibiotic mediated changes to the gut microbiota have been implicated in the aetiology of many chronic diseases. To date, studies have largely focused on how antibiotics affect the bacterial fraction of the gut microbiome and their impact on non-bacterial members, including prevalent eukaryal species, such as , remains largely unknown.

Precursor B-cell acute lymphoblastic leukaemia-a global view.

As haematologists, we always seek to follow standardised guidelines for practice and apply the best treatment within our means for our patients with blood diseases. However, treatment can never follow an exact recipe. Opinions differ as to the best approach; sometimes more than one treatment approach results in identical outcomes, or treatments differ only by the manner in which they fail.

Defining High-risk Retinoblastoma: A Multicenter Global Survey.

Importance: High-risk histopathologic features of retinoblastoma are useful to assess the risk of systemic metastasis. In this era of globe salvage treatments for retinoblastoma, the definition of high-risk retinoblastoma is evolving.

Objective: To evaluate variations in the definition of high-risk histopathologic features for metastasis of retinoblastoma in different ocular oncology practices around the world.

Evolution in a Community Context: towards Understanding the Causes and Consequences of Adaptive Evolution in the Human Gut Microbiota over Short Time Scales.

How important is adaptive evolution to the unique diversity that we can observe for each individual human gut microbiome? How do gut microbes evolve in response to changes in their environment, and how does evolution in real time impact microbial functionality in the context of host health? My interdisciplinary research uses microcosm models to test how different abiotic and biotic factors impact microbial evolution in a community context. We complement this approach by tracking focal species as they evolve in real time and in their natural environment of the human gut. Our aim is to provide a better understanding of how the dynamics and outcomes of microbial evolution differ between individual gut environments, and in response to different selection pressures, so that we can move closer to rational gut microbiome treatments that promote host health and prevent and treat human disease.

Ecological and Evolutionary responses to Antibiotic Treatment in the Human Gut Microbiota.

The potential for antibiotics to affect the ecology and evolution of the human gut microbiota is well recognised and has wide-ranging implications for host health. Here, we review the findings of key studies that surveyed the human gut microbiota during antibiotic treatment. We find several broad patterns including the loss of diversity, disturbance of community composition, suppression of bacteria in the Actinobacteria phylum, amplification of bacteria in the Bacteroidetes phylum, and promotion of antibiotic resistance.

Locally produced personal protective equipment can offer hospital staff protection against Covid-19 if combined with surgical masks and rigorous personal protective equipment cleaning routine.

Locally made, washable and reusable personal protective equipment (PPE), used in combination with N95 masks that were reused safely, has proven to be a viable alternative to disposable gowns and caps for hospital staff in low- and middle-income countries. Muhimbili University Hospital's children's cancer ward in Dar es Salaam, Tanzania, developed locally made PPE and created rigorous cleaning and disinfecting protocols, when the daily use of imported, disposable materials were not an option. These items continue to protect staff, children and parents.

Resistance May Be Futile: Gut Spatial Heterogeneity Supports Bacteria-Phage Co-existence.

How do we explain the co-existence of bacteria and bacteriophages in complex environments? In this issue of Cell Host & Microbe, Lourenço et al. highlight the importance of spatial structure in facilitating the persistence of sensitive bacterial hosts and their virulent bacteriophages in the mammalian gut.

Microbial evolution and ecological opportunity in the gut environment.

Recent genomic and metagenomic studies have highlighted the presence of rapidly evolving microbial populations in the human gut. However, despite the fundamental implications of this intuitive finding for both basic and applied gut microbiome research, very little is known about the mode, tempo and potential functional consequences of microbial evolution in the guts of individual human hosts over a lifetime. Here I assess the potential relevance of ecological opportunity to bacterial adaptation, colonization and persistence in the neonate and germ-free mammalian gut environment as well as over the course of an individual lifetime using data emerging from mouse models as well as human studies to provide examples where possible.

Impact of bile salts on coevolutionary dynamics between the gut bacterium Escherichia coli and its lytic phage PP01.

Although host and parasites are typically embedded in complex abiotic and biotic environments our understanding of how environmental variation impacts on host-parasite interactions, including antagonistic coevolution (AC) is poorly understood. Nonetheless, previous studies using bacteria and bacteriophages have shown that variation in just one abiotic parameter can have profound effects not only on the type of AC dynamics observed but also the time-frames over which AC interactions can persist. Here, we investigated the effect of an important component of the abiotic human gut environment, bile salts, on AC dynamics between the bacterium Escherichia coli and the lytic phage PP01 in an in vitro model system.

Detection of Osteoporosis from Percussion Responses Using an Electronic Stethoscope and Machine Learning.

Osteoporosis is an asymptomatic bone condition that affects a large proportion of the elderly population around the world, resulting in increased bone fragility and increased risk of fracture. Previous studies had shown that the vibroacoustic response of bone can indicate the quality of the bone condition. Therefore, the aim of the authors' project is to develop a new method to exploit this phenomenon to improve detection of osteoporosis in individuals.

The intestinal protist Blastocystis is not a common member of the healthy infant gut microbiota in a Westernized country (Ireland).

Research into the gut microbiota of human infants is necessary in order to better understand how inter-species interactions and ecological succession shape the diversity of the gut microbiota, and in turn, how the specific composition of the gut microbiota impacts on host health both during infancy and in later years. Blastocystis is a ubiquitous intestinal protist that has been linked to a number of intestinal and extra-intestinal diseases. However, emerging data show that asymptomatic carriage is common and that Blastocystis is prevalent in the healthy adult gut microbiota.

Quantitative mechanical assessment of the whole prostate gland ex vivo using dynamic instrumented palpation.

An instrumented palpation sensor, designed for measuring the dynamic modulus of tissue in vivo, has been developed and trialled on ex vivo whole prostate glands. The sensor consists of a flexible membrane sensor/actuator with an embedded strain gauge and is actuated using a dynamically varying airflow at frequencies of 1 and 5 Hz. The device was calibrated using an indentation stiffness measurement rig and gelatine samples with a range of static modulus similar to that reported in the literature for prostate tissue.

The Fungal Frontier: A Comparative Analysis of Methods Used in the Study of the Human Gut Mycobiome.

The human gut is host to a diverse range of fungal species, collectively referred to as the gut "mycobiome". The gut mycobiome is emerging as an area of considerable research interest due to the potential roles of these fungi in human health and disease. However, there is no consensus as to what the best or most suitable methodologies available are with respect to characterizing the human gut mycobiome.

Within-host interference competition can prevent invasion of rare parasites.

Competition between parasite species or genotypes can play an important role in the establishment of parasites in new host populations. Here, we investigate a mechanism by which a rare parasite is unable to establish itself in a host population if a common resident parasite is already present (a 'priority effect'). We develop a simple epidemiological model and show that a rare parasite genotype is unable to invade if coinfecting parasite genotypes inhibit each other's transmission more than expected from simple resource partitioning.

Forgotten fungi-the gut mycobiome in human health and disease.

The human body is home to a complex and diverse microbial ecosystem that plays a central role in host health. This includes a diversity of fungal species that is collectively referred to as our 'mycobiome'. Although research into the mycobiome is still in its infancy, its potential role in human disease is increasingly recognised.

Bacteria-Bacteriophage Coevolution in the Human Gut: Implications for Microbial Diversity and Functionality.

Antagonistic coevolution (AC) between bacteria and bacteriophages plays a key role in driving and maintaining microbial diversity. Consequently, AC is predicted to affect all levels of biological organisation, from the individual to ecosystem scales. Nonetheless, we know nothing about bacteria-bacteriophage AC in perhaps the most important and clinically relevant microbial ecosystem known to humankind - the human gut microbiome.

Modification of Escherichia coli-bacteriophage interactions by surfactants and antibiotics in vitro.

Although experiments indicate that the abiotic environment plays an important role in bacterial interactions with their parasitic viruses (bacteriophages or phages), it is not yet clear how exposure to compounds present in nature alters the impact of phages on bacterial growth and evolution. To address this question, we exposed Escherichia coli K12 MG1655, in combination with three lytic phages, to various substances that natural and clinical microbial populations are likely to encounter: bile salts (present in mammalian gastrointestinal tracts), sodium dodecyl sulfate (SDS, a common surfactant in cleaning and hygiene products) and four antibiotics (present at variable concentrations in natural and clinical environments). Our results show that bile salts and SDS can reduce the detrimental effect of phages on bacterial growth.

Parasite genetic distance and local adaptation in co-evolving bacteria-bacteriophage populations.

Antagonistic co-evolution between hosts and parasites can lead to local adaptation (LA) such that parasite fitness is greatest in sympatric hosts (or vice versa). The magnitude of LA typically increases with geographical distance, which is assumed to be because genetic (and hence phenotypic) distance increases with geographical distance. Here, we explicitly test the relationships between parasite genetic and phenotypic distance and LA using isolates of co-evolved viral parasites (lytic bacteriophage ϕ2) and the host bacterium Pseudomonas fluorescens SBW25.

Prevalence and genetic diversity of Blastocystis in family units living in the United States.

The human gut is host to a diversity of microorganisms including the single-celled microbial eukaryote Blastocystis. Although Blastocystis has a global distribution, there is dearth of information relating to its prevalence and diversity in many human populations. The mode of Blastocystis transmission to humans is also insufficiently characterised, however, it is speculated to vary between different populations.

Case report: Xanthogranulomutous pyelonephritis presenting as "Wilms' tumor".

Background: Xanthogranulomatous pyelonephritis (XGP) is a rare renal tumor that arises as a complication of chronic obstructive pyelonephritis of uncertain etiology. It is primarily an adult tumor seen occasionally in children associated with urinary tract obstruction due to congenital urological anomalies, nephrolithiasis, and recurrent urinary tract infections. Radiologically, it may show neoplastic features such as those seen in common pediatric renal malignancies like wilms' tumor and renal cell carcinoma.

Iron availability shapes the evolution of bacteriocin resistance in Pseudomonas aeruginosa.

The evolution of bacterial resistance to conventional antimicrobials is a widely documented phenomenon with gravely important consequences for public health. However, bacteria also produce a vast repertoire of natural antimicrobials, presumably in order to kill competing species. Bacteriocins are a common class of protein-based antimicrobials that have been shown to have an important role in the ecology and evolution of bacterial communities.