Publications by authors named "Christopher Dupont"

Article Synopsis
  • Within-patient diversity in bloodstream infections (BSIs) was investigated by sequencing strains from blood cultures of 4 patients, revealing mixed populations in 3 of them with significant genetic variations.
  • One strain variant with chromosome 7 trisomy (Tri7) from patient MN showed different growth behaviors and competitiveness compared to its euploid counterpart during infections and antifungal treatments.
  • The study suggests that diverse strain populations exist in BSIs, which could impact treatment outcomes and highlight the need for further research into their clinical significance and antifungal resistance.
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  • Extrapulmonary tuberculosis (EPTB) is a serious public health issue that often gets overlooked, so this study examines its genetic diversity, drug resistance, and transmission chains in western Ethiopia.
  • Using whole-genome sequencing on samples from EPTB patients, researchers found that 87.64% of the bacteria belonged to a dominant lineage (Lineage-4) with varying sub-lineages, and a low rate of multi-drug resistance was observed.
  • The study highlights a high clustering rate of infections, signaling the need for better TB control measures, and reveals that many drug-resistance mutations were not detected by standard diagnostic tests, showing the importance of advanced sequencing techniques.
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Background: The lineage 4 (L4) of Mycobacterium tuberculosis (MTB) is not only globally prevalent but also locally dominant, surpassing other lineages, with lineage 2 (L2) following in prevalence. Despite its widespread occurrence, factors influencing the expansion of L4 and its sub-lineages remain poorly understood both at local and global levels. Therefore, this study aimed to conduct a pan-genome and identify genomic signatures linked to the elevated prevalence of L4 sublineages among extrapulmonary TB (EPTB) patients in western Ethiopia.

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Unlabelled: The physiology and ecology of particle-associated marine bacteria are of growing interest, but our knowledge of their aggregation behavior and mechanisms controlling their association with particles remains limited. We have found that a particle-associated isolate, sp. ALT199 strain 4B03, and the related type-strain 27126 both form large (>500 μm) aggregates while growing in rich medium.

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Iron is an essential nutrient for all microorganisms of the marine environment. Iron limitation of primary production has been well documented across a significant portion of the global surface ocean, but much less is known regarding the potential for iron limitation of the marine heterotrophic microbial community. In this work, we characterize the transcriptomic response of the heterotrophic bacterial community to iron additions in the California Current System, an eastern boundary upwelling system, to detect in situ iron stress of heterotrophic bacteria.

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Established evidence indicates that oral microbiota plays a crucial role in modulating host immune responses to viral infection. Following severe acute respiratory syndrome coronavirus 2, there are coordinated microbiome and inflammatory responses within the mucosal and systemic compartments that are unknown. The specific roles the oral microbiota and inflammatory cytokines play in the pathogenesis of coronavirus disease 2019 (COVID-19) are yet to be explored.

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While diatoms are promising synthetic biology platforms, there currently exists a limited number of validated genetic regulatory parts available for genetic engineering. The standard method for diatom transformation, nonspecific introduction of DNA into chromosomes via biolistic particle bombardment, is low throughput and suffers from clonal variability and epigenetic effects. Recent developments in diatom engineering have demonstrated that autonomously replicating episomal plasmids serve as stable expression platforms for diverse gene expression technologies.

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  • Traditional belief held that bloodstream infections (BSIs) were primarily caused by a single organism, but this study reveals mixed populations of genetically diverse strains of Candida glabrata in patients.
  • Whole genome sequencing showed distinct genetic differences among these strains, impacting their susceptibility to antifungal treatments and their ability to evade the immune system.
  • Findings indicate that the persistence and relapse of infections may be linked to a diversity of drug-resistant strains, highlighting the need for a population-based understanding of C. glabrata during BSIs.
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Millions of people are suffering from Long COVID or post-acute sequelae of COVID-19 (PASC). Several biological factors have emerged as potential drivers of PASC pathology. Some individuals with PASC may not fully clear the coronavirus SARS-CoV-2 after acute infection.

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  • This study compares the effectiveness of two DNA extraction kits (DNeasy PowerSoil Kit and DNeasy PowerLyzer PowerSoil Kit) in detecting pathogens from samples collected from the nasopharynx/oropharynx (NP/OP).
  • Results showed that the PowerLyzer kit yielded higher DNA concentrations and better detection rates for pathogens like S. pneumoniae, H. influenzae, and N. meningitidis compared to the discontinued kit.
  • The findings suggest that using the more efficient kit could improve the recovery of low-abundance bacteria in clinical settings, but researchers should consider potential Ct value discrepancies when comparing results across studies utilizing different kits.
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  • * Researchers analyzed saliva and blood samples from COVID-19 patients of varying severity and found that changes in the salivary microbiome correlated with the severity of the disease.
  • * The findings suggest that examining the oral microbiome and cytokine levels in saliva could help predict COVID-19 status and severity, offering insights into how the body responds to the virus.
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During inflammation, the skin deploys antimicrobial peptides (AMPs) yet during allergic inflammation it becomes more susceptible to Staphylococcus aureus. To understand this contradiction, single-cell sequencing of Il4ra mice combined with skin microbiome analysis reveals that lower production of AMPs from interleukin-4 receptor α (IL-4Rα) activation selectively inhibits survival of antibiotic-producing strains of coagulase-negative Staphylococcus (CoNS). Diminished AMPs under conditions of T helper type 2 (Th2) inflammation enable expansion of CoNS strains without antibiotic activity and increase Staphylococcus aureus (S.

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  • - The study investigates how microbial communities form on microplastics in the ocean, focusing on early plastic biofilm development by comparing them to older, naturally occurring plastic litter.
  • - Early colonizers of microplastics were primarily Alteromonadaceae, showing genes linked to adhesion and motility, while mature biofilms were mainly Rhodobacteraceae with genes for carbohydrate breakdown and photosynthesis.
  • - Key findings reveal that the MSHA operon in Alteromonadaceae enhances their competitive advantage for colonizing plastic surfaces, even though genetic traits of early colonizers remain largely stable despite changing environments.
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Article Synopsis
  • * Whole genome sequencing of strains from blood cultures of ten patients revealed that these mixed populations can have significant differences in their susceptibility to antifungal treatments.
  • * The study indicates that this genetic diversity can lead to the recovery of both susceptible and resistant strains during infections, suggesting a need for a new understanding of how these infections behave and progress.
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Most of the discarded waste material paves their way to the utmost common dumping grounds, Landfills. Despite their widespread use, the landfill microbiomes are still not well characterized. Metagenomics approach provides insight into the identification of operational parameters influencing the microbiome composition and their biodegradation competencies.

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  • This study investigates the roles of gut microbiota, pathogens, and hormones in severe acute malnutrition (marasmus SAM) and moderate acute malnutrition (MAM) in young children in rural Gambia.
  • Researchers used association networks to analyze how these factors contribute to the severity of acute malnutrition.
  • Findings indicate that children with marasmus SAM have unique gut microbiome profiles and lower microbial diversity, along with specific interactions between gut bacteria and energy-regulating hormones, which underscores the need for further research for new interventions.
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Beneficial microorganisms for corals (BMCs) ameliorate environmental stress, but whether they can prevent mortality and the underlying host response mechanisms remains elusive. Here, we conducted omics analyses on the coral exposed to bleaching conditions in a long-term mesocosm experiment and inoculated with a selected BMC consortium or a saline solution placebo. All corals were affected by heat stress, but the observed "post-heat stress disorder" was mitigated by BMCs, signified by patterns of dimethylsulfoniopropionate degradation, lipid maintenance, and coral host transcriptional reprogramming of cellular restructuration, repair, stress protection, and immune genes, concomitant with a 40% survival rate increase and stable photosynthetic performance by the endosymbiotic algae.

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It is now widely accepted that siderophores play a role in marine iron biogeochemical cycling. However, the mechanisms by which siderophores affect the availability of iron from specific sources and the resulting significance of these processes on iron biogeochemical cycling as a whole have remained largely untested. In this study, we develop a model system for testing the effects of siderophore production on iron bioavailability using the marine copiotroph Alteromonas macleodii ATCC 27126.

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  • S. aureus colonization was significantly more prevalent in South African toddlers with atopic dermatitis (AD) compared to those without, with rates of 54% in rural Umtata and 70% in urban Cape Town.
  • Among urban toddlers, more severe AD correlated with higher colonization rates (86% for severe vs. 52% for moderate), reinforcing a link between disease severity and bacterial presence.
  • Environmental factors also influenced colonization, with electrified homes using gas or kerosene showing higher rates, while exposure to farm animals and traditional cooking methods provided protective effects against S. aureus colonization.
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Mucormycoses are invasive infections by species and other Mucorales. Over 10 months, four solid organ transplant (SOT) recipients at our centre developed mucormycosis due to (=2), (=1) or (=1), at a median 31.5 days (range: 13-34) post-admission.

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  • The study focuses on Nitrospira marina Nb-295, a marine nitrite-oxidizing bacterium with an unexamined genome, to explore its metabolic abilities and adaptations in ocean environments.
  • Researchers confirmed that N. marina thrives on various organic carbon sources, can resist stressful conditions like low oxygen and UV light, and requires vitamin B, showcasing its metabolic versatility.
  • The analysis revealed that under low oxygen, N. marina enhances certain protein systems for efficient energy utilization, indicating its ability to adapt to changes in oxygen levels and maintain its role in nitrite oxidation in marine ecosystems.
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The present study discusses the genomic analysis of Bacillus sp. ISTL8 along with the production of EPS (Extracellular polymeric substances) using carbofuran, a toxic carbamate pesticide. Bacillus strain was isolated from landfill soil and evaluated for high growth rates and EPS production.

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We present METATRYP version 2 software that identifies shared peptides across the predicted proteomes of organisms within environmental metaproteomics studies to enable accurate taxonomic attribution of peptides during protein inference. Improvements include ingestion of complex sequence assembly data categories (metagenomic and metatranscriptomic assemblies, single cell amplified genomes, and metagenome assembled genomes), prediction of the least common ancestor (LCA) for a peptide shared across multiple organisms, increased performance through updates to the backend architecture, and development of a web portal (https://metatryp.whoi.

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