Multilocus sequence typing supports the hypothesis that Ochrobactrum anthropi displays a human-associated subpopulation

<p>Abstract</p> <p>Background</p> <p><it>Ochrobactrum anthropi </it>is a versatile bacterial species with strains living in very diverse habitats. It is increasingly recognized as opportunistic pathogen in hospitalized patients. The population biology of the species particularly with regard to the characteristics of the human isolates is being investigated. To address this issue, we proposed a polyphasic approach consisting in Multi-Locus Sequence Typing (MLST), multi-locus phylogeny, genomic-based fingerprinting by pulsed-field gel electrophoresis (PFGE) and antibiotyping.</p> <p>Results</p> <p>We tested a population of 70 <it>O. anthropi </it>clinical (n = 43) and environmental (n = 24) isolates as well as the type strain <it>O. anthropi </it>ATCC49188^Tand 2 strains of <it>Ochrobactrum lupini </it>and <it>Ochrobactrum cytisi </it>isolated from plant nodules. A Multi-Locus Sequence Typing (MLST) scheme for <it>O. anthropi </it>is proposed here for the first time. It was based on 7 genes (3490 nucleotides) evolving mostly by neutral mutations. The MLST approach suggested an epidemic population structure. A major clonal complex corresponded to a human-associated lineage since it exclusively contained clinical isolates. Genomic fingerprinting separated isolates displaying the same sequence type but it did not detect a population structure that could be related to the origin of the strains. None of the molecular method allowed the definition of particular lineages associated to the host-bacteria relationship (carriage, colonisation or infection). Antibiotyping was the least discriminative method.</p> <p>Conclusion</p> <p>The results reveal a human-associated subpopulation in our collection of strains. The emergence of this clonal complex was probably not driven by the antibiotic selective pressure. Therefore, we hypothesise that the versatile species <it>O. anthropi </it>could be considered as a human-specialized opportunistic pathogen.</p

Niches, Population Structure and Genome Reduction in Ochrobactrum intermedium: Clues to Technology-Driven Emergence of Pathogens

International audienceOchrobactrum intermedium is considered as an emerging human environmental opportunistic pathogen with mild virulence. The distribution of isolates and sequences described in literature and databases showed frequent association with human beings and polluted environments. As population structures are related to bacterial lifestyles, we investigated by multi-locus approach the genetic structure of a population of 65 isolates representative of the known natural distribution of O. intermedium. The population was further surveyed for genome dynamics using pulsed-field gel electrophoresis and genomics. The population displayed a clonal epidemic structure with events of recombination that occurred mainly in clonal complexes. Concerning biogeography, clones were shared by human and environments and were both cosmopolitan and local. The main cosmopolitan clone was genetically and genomically stable, and grouped isolates that all harbored an atypical insertion in the rrs. Ubiquitism and stability of this major clone suggested a clonal succes in a particular niche. Events of genomic reduction were detected in the population and the deleted genomic content was described for one isolate. O. intermedium displayed allopatric characters associated to a tendancy of genome reduction suggesting a specialization process. Considering its relatedness with Brucella, this specialization might be a commitment toward pathogenic life-style that could be driven by technological selective pressure related medical and industrial technologies

Antibacterial Activity of Wild Mushrooms Antibacterial Activity of Wild Mushrooms from France

International audienceWe selected seven wild Basidiomycota and Ascomycota mushrooms to evaluate their antibacterial activity: Cyclocybe aegerita, Cortinarius traganus, Gyroporus castaneus, Neoboletus luridiformis, Rubroboletus lupinus, Gyromitra esculenta, and Helvella crispa. Four mushrooms, three of which have never been tested, display antibacterial potential with MIC≤125 µg/mL against at least one Gram-positive bacterial strain. The cyclohexanic extract of G. esculenta possesses the strongest antibacterial activity with MIC=31 µg/mL against two strains of Staphylococcus aureus

Exploration of antimicrobial resistant communities in Montpellier area. Evaluation of innovative microbial indicators of anthropic pressure - Poster

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Pulsed-field gel electrophoresis to study the diversity of whole-genome organization in the genusOchrobactrum

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Freeze-casted bioglass-PDLLA nanocomposite scaffolds for mandibular osteoradionecrosis treatment: from building units design to preliminary in vivo study.

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Tracking carbapenemase-producing bacteria by molecular typing: Population diversity and sampling pitfall

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Distribution of the 171 strains (n = 148) and clones (n = 23) of <i>O. intermedium</i>/<i>O. ciceri</i> identified from the litterature and databases according to the habitat.

<p>The figure has been constructed from data presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083376#pone.0083376.s003" target="_blank">Tables S1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083376#pone.0083376.s004" target="_blank">S2</a>.</p

Epidémie clonale à Klebsiella pneumoniae BLSE en néonatalogie relayée par les matelas des incubateurs.

International audienceEn néonatalogie, les dépistages hebdomadaires de portagedigestif de bactéries multirésistantes ont détecté simultanément3 enfants porteurs de Klebsiella pneumoniae produtrice debêtalactamase à spectre étendu (BLSE) en novembre 2015.Une investigation a été conduite pour évaluer le nombre de caset analyser les causes

NDM-5-producing Escherichia coli in an urban river in Montpellier, France

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