Biology subjects

Antoni, R.

Publications and source records attributed to Antoni, R..

3 recordsLinked to original sources

bioRxiv2026

Multihospital expansion of vancomycin-resistant Enterococcus faecium ST117-CT7799 and transmission of linear plasmids co-carrying vanA and linezolid resistance genes, Comunitat Valenciana, Spain (2022-2024)

BackgroundVancomycin-resistant Enterococcus faecium (VREfm) is a WHO priority pathogen. In the Comunitat Valenciana (CV), Spain, VREfm prevalence has increased since 2022. We characterized the population structure, transmission patterns and resistance determinants of VREfm across eight hospitals (2021-2024). MethodsEight hospitals reported 870 VREfm cases during 2021-2024. We sequenced 254 VREfm isolates using WGS (Illumina) and inferred relatedness by MLST, cgMLST, and core-genome SNP analyses. Acquired antimicrobial resistance (AMR) genes, bacteriocins, plasmid replicases and putative virulence markers (PVMs) were identified in silico. Thirty-eight representatives underwent Nanopore long-read sequencing and hybrid assembly to resolve plasmids. ResultsThe predominant vancomycin-resistance genotype was vanB (62%; six hospitals), followed by vanA (19%; five hospitals) and vanA+vanB (17%; five hospitals). Eight sequence types (ST) and 15 clonal complexes (CT) were identified, grouped into seven main phylogenetic clades with close relatedness to publicly available genomes from other regions of Spain and Europe. A single lineage, ST117-CT7799, accounted for 198/254 (78%) isolates, persisted during 2022-2024 across seven hospitals and was enriched in the bacteriocin gene bac43 (or T8) (84%). Linezolid-resistance genes optrA and cfr(D) were present in 34% of isolates, most of which also carried vanA (32%). Hybrid assemblies revealed a diverse plasmidome including RepA_N megaplasmids with PVMs and AMR genes, and small Rep3-like plasmids harbouring bacteriocins (bac43, bac51, bacAS9); a 6 kb repA_pB82 plasmid was bac43-positive in 37/38 (97%) fully resolved carriers. Eight strains across four hospitals carried identical linear plasmids co-harbouring vanA, optrA, cfrD genes within a widespread repUS78_pZY2 background, consistent with inter-lineage plasmid transmission. ConclusionsThis first comprehensive genomic analysis of VREfm in CV indicates extensive inter-hospital spread dominated by expansion of ST117-CT7799 and highlights plasmid-mediated convergence of vancomycin and linezolid resistance via linear plasmids. Strengthened infection prevention and genomic surveillance, including long-read sequencing to track linear plasmids, are warranted.

microbiology↗

bioRxiv2019

The genome sequence of the octocoral Paramuricea clavata - a key resource to study the impact of climate change in the Mediterranean

The octocoral, Paramuricea clavata, is a habitat-forming anthozoan with a key ecological role in rocky benthic and biodiversity-rich communities in the Mediterranean and Eastern Atlantic. Shallow populations of P. clavata in the North-Western Mediterranean are severely affected by warming-induced mass mortality events (MMEs). These MMEs have differentially impacted individuals and populations of P. clavata (i.e. varied levels of tissue necrosis and mortality rates) over thousands of kilometers of coastal areas. The eco-evolutionary processes and genetic factors contributing to these differential responses remain to be characterized. Here, we sequenced a P. clavata individual with short and long read technologies, producing 169.98 Gb of Illumina paired-end and 3.55 Gb of Oxford Nanopore Technologies (ONT) reads. We obtained a de novo hybrid assembly accounting for 712.4 Mb and 107,682 scaffolds. The contig and scaffold N50 are 15.85 Kb and 17.01 Kb, respectively. Despite of the low contiguity of the assembly, the gene completeness was relatively high, including 86% of the 978 metazoan genes contained in the metazoa_odb9 database. A total of 76,508 protein-coding genes and 85,763 transcripts have been annotated. This assembly is one of the few octocoral genomes currently available. This is undoubtedly a valuable resource for characterizing the genetic bases of the differential responses to thermal stress and for the identification of thermo-resistant individuals and populations. Overall, the genome of P. clavata will help to understand various aspects of its evolutionary ecology and to elaborate effective conservation plans such as active restoration actions to overcome the threats of global change.

genomics↗

bioRxiv2019

The fungal sesquiterpenoid pyrenophoric acid B uses the plant ABA biosynthetic pathway to inhibit seed germination.

HighlightThe fungus Pyrenophora semeniperda produces pyrenophoric acid B, a small molecule that exploits the plant ABA biosynthetic pathway to reduce seed germination, increasing its reproductive success.\n\nAbstractPyrenophoric acid (P-Acid), P-Acid B and P-Acid C are three phytotoxic sesquiterpenoids produced by the ascomycete seed pathogen Pyrenophora semeniperda, a fungus proposed as a mycoherbicide for biocontrol of cheatgrass, an extremely invasive weed. When tested in cheatgrass bioassays these metabolites were able to delay seed germination, with P-Acid B being the most active compound. Here, we have investigated the cross-kingdom activity of P-Acid B and its mode of action and found that it activates the ABA signaling pathway in order to inhibit seedling establishment. P-Acid B inhibits seedling establishment in wild-type Arabidopsis thaliana while several mutants affected in the early perception as well as in downstream ABA signaling components were insensitive to the fungal compound. However, in spite of structural similarities between ABA and P-Acid B, the latter is not able to activate the PYR/PYL family of ABA receptors. Instead, we have found that P-Acid B uses the ABA biosynthesis pathway at the level of alcohol dehydrogenase ABA2 to reduce seedling establishment. We propose that the fungus Pyrenophora semeniperda manipulates plant ABA biosynthesis as a strategy to reduce seed germination, increasing its ability to cause seed mortality and thereby increase its fitness through higher reproductive success.

plant biology↗