Objectives: Clostridium difficile is a major global human pathogen divided into five clades, of which clade 3 is the least characterized and consists predominantly of PCR ribotype (RT) 023 strains. Our aim was to analyse and characterize this clade.
Methods: In this cohort study the clinical presentation of C. difficile RT023 infections was analysed in comparison with known 'hypervirulent' and non-hypervirulent strains, using data from the Netherlands national C. difficile surveillance programme. European RT023 strains of diverse origin were collected and whole-genome sequenced to determine the genetic similarity between isolates. Distinctive features were investigated and characterized.
Results: Clinical presentation of C. difficile RT023 infections show severe infections akin to those seen with 'hypervirulent' strains from clades 2 (RT027) and 5 (RT078) (35%, 29% and 27% severe CDI, respectively), particularly with significantly more bloody diarrhoea than RT078 and non-hypervirulent strains (RT023 8%, other RTs 4%, p 0.036). The full genome sequence of strain CD305 is presented as a robust reference. Phylogenetic comparison of CD305 and a further 79 previously uncharacterized European RT023 strains of diverse origin revealed minor genetic divergence with >99.8% pairwise identity between strains. Analyses revealed distinctive features among clade 3 strains, including conserved pathogenicity locus, binary toxin and phage insertion toxin genotypes, glycosylation of S-layer proteins, presence of the RT078 four-gene trehalose cluster and an esculinase-negative genotype.
Conclusions: Given their recent emergence, virulence and genomic characteristics, the surveillance of clade 3 strains should be more highly prioritized.
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http://dx.doi.org/10.1016/j.cmi.2019.09.004 | DOI Listing |
Ecotoxicol Environ Saf
January 2025
Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical school, University of South China, Hengyang, Hunan 421001, China. Electronic address:
Microcystin LR (MC-LR) pollution is a serious threat to aquatic ecosystems and public health in China and is an environmental problem that urgently needs to be solved. However, few studies have investigated the anaerobic degradation pathway and related molecular biological mechanisms of MC-LR. In this study, a bacterium capable of degrading MC-LR with a degradation efficiency of 0.
View Article and Find Full Text PDFHybridisation is a source of genetic diversity, can drive adaptation to new niches and has been found to be a frequent event in lineages harbouring pathogenic fungi. However, little is known about the genomic implications of hybridisation nor its impact on pathogenicity-related traits. A common limitation for addressing these questions is the narrow representativity of sequenced genomes, mostly corresponding to strains isolated from infected patients.
View Article and Find Full Text PDFPLoS Pathog
January 2025
Graduate Program in Immunology, Ann Arbor, Michigan, United States of America.
Neutrophils play key protective roles in influenza infections, yet excessive neutrophilic inflammation is a hallmark of acute lung injury during severe infections. Phenotypic heterogeneity is increasingly recognized in neutrophil populations; however, how functional variation in neutrophils between individuals determine the diverse outcomes of influenza remains unclear. To examine immunologic responses that may drive varying outcomes in influenza, we infected C57BL/6 (B6) and A/J mice with mouse-adapted influenza A virus A/PR/8/34 H1N1.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, 1098 XH Amsterdam, Netherlands.
We present the synthesis, structural analysis, and remarkable reactivity of the first carbon nanohoop that fully incorporates ferrocene in the macrocyclic backbone. The high strain imposed on the ferrocene by the curved nanohoop structure enables unprecedented photochemical reactivity of this otherwise photochemically inert metallocene complex. Visible light activation triggers a ring-opening of the nanohoop structure, fully dissociating the Fe-cyclopentadienyl bonds in the presence of 1,10-phenanthroline.
View Article and Find Full Text PDFMol Biol Evol
January 2025
Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
The study of mutational processes in somatic genomes has gained recent momentum, uncovering a wide array of endogenous and exogenous factors associated with somatic changes. However, the overall landscape of mutational processes in germline mutations across the tree of life and associated evolutionary driving forces are rather unclear. In this study, we analyzed mutational processes in single-stranded RNA (ssRNA) viruses which are known to jump between different hosts with divergent exogenous environments.
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