Microbial risk assessment of Nocardia cyriacigeorgica in polluted environments, case of urban rainfall water

International audienceUrban Infiltration Basins (UIBs) are used to manage urban runoff transfers and feed aquifers. These UIBs can accumulate urban pollutants and favor the growth of potentially pathogenic biological agents as Nocardia.Objectives: To assess the spatio-temporal dynamics of pathogenic Nocardia in UIBs and to stablish phylogenetic relationships between clinical and UIB N. cyriacigeorgica strains. To assess pathogenicity associated with environmental N. cyriacigeorgica using an animal model, and to identify genetic elements that may be associated to its virulence.Methods: A well-characterized UIB in terms of chemical pollutants from Lyon area was used in this study during a whole year. Cultural and Next-Generation-Sequencing methods were used for Nocardia detection and typing. Clinical and environmental isolates phylogenetic relationships and virulences were compared with Multilocus-Sequence-Analysis study together with a murine model.Results: In autumn, N. cyriacigeorgica and N. nova were the pathogenic most prevalent species in the UIB. The complex N. abscessus/asiatica was also detected together with some other non-pathogenic species. The presence of pathogenic Nocardia was positively correlated to metallic trace elements. Up to 1.0 x 10(3) CFU/g sediment of N. cyriacigeorgica and 6 OTUs splited in two different phylogroups were retrieved and were close to clinical strains. The EML446 tested UIB isolate showed significant infectivity in mice with pulmonary damages similar to clinical clone (GUH-2).Conclusion: Hsp65 marker-based metabarcoding approach allowed detecting N. cyriacigeogica as the most abundant Nocardia pathogenic species in a UIB. Metal trace elements-polluted environments can be reservoirs of pathogenic Nocardia which may have a similar virulence to clinical strains. (C) 2020 The Author(s). Published by Elsevier B.V. on behalf of Research Network of Computational and Structural Biotechnology

First case of actinomycetoma in France due to a novel nocardia species, nocardia boironii sp nov.

Bacterial mycetoma is a neglected disease mainly observed in tropical area countries and typically associated with rural conditions, making its presence in developed countries of temperate climate areas rare. However, we report the first case of an autochthonous mycetoma case in continental France that originated from a new Nocardia species. A Gram-positive filamentous bacterium (OFN 14.177T) was isolated from a pus sample from the mycetoma of a male French patient 92 years old suffering from chronic lymphocytic leukemia. The isolate was analyzed by a polyphasic taxonomic approach by coupling morphological, biochemical, physiological, and chemotaxonomic aspects to genomic and phylogenetic analyses. Multilocus sequence analysis (MLSA) using four housekeeping genes (16S rRNA gene, secA1, hsp65, and sod) combined with phylogenetic analysis revealed that the strain OFN 14.177T is phylogenetically closer not only to Nocardia altamirensis but also to all other species comprising the Nocardia brasiliensis clade (i.e., N. brasiliensis, N. altamirensis, N. vulneris, N. iowensis, and N. tenerifensis), some of which present cutaneous tropism. The G+C content of isolate OFN 14.177T was 68.2 mol%. DNA-DNA hybridization analyses demonstrated 38.25% relative reassociation with N. altamirensis. The strain OFN 14.177T is different from the closest species at genetic and phenotypical levels, and the data obtained indicate that it should be recognized as a new species, for which the name of Nocardia boironii sp. nov. is proposed. The type strain is OFN 14.177T (= EML 1451 = DSM 101696).IMPORTANCE Bacterial mycetoma is an endemic infection in areas with tropical and subtropical climates. Thus, its presence in temperate climate areas remains rare. We report here the first case of autochthonous actinomycetoma in continental France originating from a Nocardia species other than N. brasiliensis, namely, Nocardia boironii. Considering the history of the patient, the infection source of strain OFN 14.177T may be from frequent contact with the soil over many years because of his gardening activities. The discovery of a French autochthonous Nocardia species responsible for actinomycetoma reveals the importance of considering the possibility of having autochthonous infections of this type in nontropical countries, not only imported cases from tropical countries. However, further studies are needed to elucidate the real incidence of this new species

Primer reporte de infección natural por Nocardia cyriacigeorgica en ratones BALB/c

Las bacterias del géneroNocardia  son actinomicetos aerobios cuyo hábitat es el suelo y la materia orgánica en descomposición.La infección natural por especies de este género ha sido reportada en humanos y animales, sin embargo, la infección natural en ratones no ha sido descrita. En este estudio se demuestra por primera vez el aislamiento de la especie recientemente descrita, Nocardia cyriacigeorgica , en pulmones de ratones Balb/c. El estudio microbiológico de las muestras de pulmón reportó la presencia de filamentos grampositivos ramificados fragmentados en forma cocobacilares. Los estudios de PCR demostraron que la especie aislada fue N. cyriacigeorgica  Se evidencia en este trabajo que N. cyriacigeorgica  es potencialmente patógena en ratones Balb/c