BACKGROUND: Hantaviruses are single-stranded RNA viruses, which are transmitted to humans primarily via inhalation of aerosolised virus in contaminated rodent urine and faeces. Whilst infected ...reservoir hosts are asymptomatic, human infections can lead to two clinical manifestations, haemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS), with varying degrees of clinical severity. The incidence of rodent and human cases of Seoul virus (SEOV) in Europe has been considered to be low, and speculated to be driven by the sporadic introduction of infected brown rats (Rattus norvegicus) via ports. METHODS: Between October 2010 and March 2012, 128 brown rats were caught at sites across the Lyon region in France. RESULTS: SEOV RNA was detected in the lungs of 14% (95% CI 8.01 – 20.11) of brown rats tested using a nested pan-hantavirus RT-PCR (polymerase gene). Phylogenetic analysis supports the inclusion of the Lyon SEOV within Lineage 7 with SEOV strains originating from SE Asia and the previously reported French & Belgian SEOV strains. Sequence data obtained from the recent human SEOV case (Replonges) was most similar to that obtained from one brown rat trapped in a public park in Lyon city centre. We obtained significantly improved recovery of virus genome sequence directly from SEOV infected lung material using a simple viral enrichment approach and NGS technology. CONCLUSIONS: The detection of SEOV in two wild caught brown rats in the UK and the multiple detection of SEOV infected brown rats in the Lyon region of France, suggests that SEOV is circulating in European brown rats. Under-reporting and difficulties in identifying the hantaviruses associated with HFRS may mask the public health impact of SEOV in Europe.
With a great diversity in gene composition, including multiple putative antibiotic resistance genes, AbaR islands are potential contributors to multidrug resistance in Acinetobacter baumannii . ...However, the effective contribution of AbaR to antibiotic resistance and bacterial physiology remains elusive. To address this, we sought to accurately remove AbaR islands and restore the integrity of their insertion site. To this end, we devised a versatile scarless genome editing strategy.
In this paper, the construction and evaluation of a chromosomal expression platform (CEP), which allows controlled gene expression following ectopic integration into the chromosome of Streptococcus ...pneumoniae, is described. CEP is based on the well-studied maltosaccharide-inducible system. To facilitate integration at CEP, a plasmid, pCEP, capable of replication in Escherichia coli, but not in S. pneumoniae, was assembled. This plasmid contains an expression/selection cassette flanked on each side by more than 2 kb of pneumococcal DNA. The cassette comprises a maltose-inducible promoter, P(M), separated from a kanamycin-resistance gene by NcoI and BamHI cloning sites. Clones harbouring the gene of interest integrated at CEP under the control of P(M) can be obtained through direct transformation of an S. pneumoniae recipient with ligation products between that gene and NcoI/BamHI-digested pCEP DNA, followed by selection for kanamycin-resistant transformants.
Abstract
Objectives
To characterize Acinetobacter baumannii strains co-producing the ESBL CTX-M-115 and carbapenem-hydrolysing class D β-lactamases (CHDLs), and to assess the potential diffusion of ...their resistance genes by horizontal transfer.
Methods
Nineteen CTX-M-115/CHDL-positive A. baumannii were collected between 2015 and 2019 from patients hospitalized in France. Their whole-genome sequences were determined on Illumina and Oxford Nanopore platforms and were compared through core-genome MLST (cgMLST) and SNP analyses. Transferability of resistance genes was investigated by natural transformation assays.
Results
Eighteen strains were found to harbour CHDL OXA-72, and another one CHDL OXA-23, in addition to CTX-M-115, narrow-spectrum β-lactamases and aminoglycoside resistance determinants including ArmA. cgMLST typing, as well as Oxford Scheme ST and K locus typing, confirmed that 17 out of the 18 CTX-M-115/OXA-72 isolates belonged to new subclades within clonal complex 78 (CC78). The chromosomal region carrying the blaCTX-M-115 gene appeared to vary greatly both in gene content and in length (from 20 to 79 kb) among the strains, likely because of IS26-mediated DNA rearrangements. The blaOXA-72 gene was localized on closely related plasmids showing structural variations that occurred between pdif sites. Transfer of all the β-lactamase genes, as well as aminoglycoside resistance determinants to a drug-susceptible A. baumannii recipient, was easily obtained in vitro by natural transformation.
Conclusions
This work highlights the propensity of CC78 isolates to collect multiple antibiotic resistance genes, to rearrange and to pass them to other A. baumannii strains via natural transformation. This process, along with mobile genetic elements, likely contributes to the considerable genomic plasticity of clinical strains, and to the diversity of molecular mechanisms sustaining their multidrug resistance.
La famille des Bunyaviridae est très importante en santé publique et vétérinaire. Avec plus de 350 virus identifiés à ce jour, elle regroupe des virus transmis principalement par des arthropodes ...(arbovirus) ou des rongeurs (robovirus), responsables d’infections chez les mammifères et chez les plantes pour le genre Tospovirus. L’homme peut être infecté par une soixantaine de ces Bunyaviridae, parfois avec des conséquences très graves, voire fatales. Les exemples du virus de Schmallenberg, du virus de la fièvre de la Vallée du Rift et du genre viral hantavirus illustrent parfaitement les nombreuses incertitudes concernant cette famille virale quant à leur potentiel d’émergence, leur pouvoir pathogène très varié pour des hôtes divers, et leur capacité à persister chez différents vecteurs appartenant aux arthropodes ou aux rongeurs et, plus récemment, aux soricomorphes (insectivores).
Increasing importance of Bunyaviridae in public and veterinary health illustrated by hantaviruses, and the schmallenberg and rift valley fever viruses
The virus family of Bunyaviridae is very important in terms of public health and veterinary medicine. With over 350 viruses identified to date, it includes viruses mainly transmitted by arthropods (arboviruses) or rodents (roboviruses), infecting mammals and plants for the genus Tospovirus. Humans can be infected by around 60 bunyaviruses sometime with very serious or even fatal consequences. The examples of Schmallenberg and Rift Valley fever viruses and hantavirus genus illustrate perfectly the many questions surrounding the Bunyaviridae family’s capacity to emerge, widely variable pathogenicity for different hosts, and capacity to persist in different vectors such as arthropods or rodents and more recently the soricomorph species (insectivores).
Bacterial spores are resistant to a wide range of chemical and physical insults that are normally lethal for the vegetative form of the bacterium. While the integrity of the protein coat of the spore ...is crucial for spore survival in vitro, far less is known about how the coat provides protection in vivo against predation by ecologically relevant hosts. In particular, assays had characterized the in vitro resistance of spores to peptidoglycan-hydrolyzing enzymes like lysozyme that are also important effectors of innate immunity in a wide variety of hosts. Here, we use the bacteriovorous nematode Caenorhabditis elegans, a likely predator of Bacillus spores in the wild, to characterize the role of the spore coat in an ecologically relevant spore-host interaction. We found that ingested wild-type Bacillus subtilis spores were resistant to worm digestion, whereas vegetative forms of the bacterium were efficiently digested by the nematode. Using B. subtilis strains carrying mutations in spore coat genes, we observed a correlation between the degree of alteration of the spore coat assembly and the susceptibility to the worm degradation. Surprisingly, we found that the spores that were resistant to lysozyme in vitro can be sensitive to C. elegans digestion depending on the extent of the spore coat structure modifications. PUBLICATION ABSTRACT
The virus family of Bunyaviridae is very important in terms of public health and veterinary medicine. With over 350 viruses identified to date, it includes viruses mainly transmitted by arthropods ...(arboviruses) or rodents (roboviruses), infecting mammals and plants for the genus Tospovirus. Humans can be infected by around 60 bunyaviruses sometime with very serious or even fatal consequences. The examples of Schmallenberg and Rift Valley fever viruses and hantavirus genus illustrate perfectly the many questions surrounding the Bunyaviridae family's capacity to emerge, widely variable pathogenicity for different hosts, and capacity to persist in different vectors such as arthropods or rodents and more recently the soricomorph species (insectivores).
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