title: Brucella spp. of amphibians comprise genomically diverse motile strains competent for replication in macrophages and survival in mammalian hosts.
abstract: Twenty-one small Gram-negative motile coccobacilli were isolated from 15 systemically diseased African bullfrogs (Pyxicephalus edulis), and were initially identified as Ochrobactrum anthropi by standard microbiological identification systems. Phylogenetic reconstructions using combined molecular analyses and comparative whole genome analysis of the most diverse of the bullfrog strains verified affiliation with the genus Brucella and placed the isolates in a cluster containing B. inopinata and the other non-classical Brucella species but also revealed significant genetic differences within the group. Four representative but molecularly and phenotypically diverse strains were used for in vitro and in vivo infection experiments. All readily multiplied in macrophage-like murine J774-cells, and their overall intramacrophagic growth rate was comparable to that of B. inopinata BO1 and slightly higher than that of B. microti CCM 4915. In the BALB/c murine model of infection these strains replicated in both spleen and liver, but were less efficient than B. suis 1330. Some strains survived in the mammalian host for up to 12 weeks. The heterogeneity of these novel strains hampers a single species description but their phenotypic and genetic features suggest that they represent an evolutionary link between a soil-associated ancestor and the mammalian host-adapted pathogenic Brucella species.
authors.affiliation: German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, Berlin, Germany.|RWTH Aachen University, Department of Internal Medicine III, Aachen, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: Al Dahouk
authors.affiliation: Université Montpellier, Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé (CPBS), Montpellier, France.|CNRS, FRE3689, CPBS, Montpellier, France.
authors.forename: Stephan
authors.initials: S
authors.lastname: Köhler
authors.affiliation: Université Montpellier, Centre d'études d'agents Pathogènes et Biotechnologies pour la Santé (CPBS), Montpellier, France.|CNRS, FRE3689, CPBS, Montpellier, France.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Occhialini
authors.affiliation: Unidad de Producción y Sanidad Animal, Centro de Investigación y Tecnología Agroalimentaria, Instituto Agroalimentario de Aragón - IA2 (CITA-Universidad de Zaragoza), Zaragoza, Spain.
authors.forename: María Pilar
authors.initials: MP
authors.lastname: Jiménez de Bagüés
authors.affiliation: German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, Berlin, Germany.
authors.forename: Jens Andre
authors.initials: JA
authors.lastname: Hammerl
authors.affiliation: Landesbetrieb Hessisches Landeslabor, Gießen, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Eisenberg
authors.affiliation: I2BC, CNRS, CEA, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Vergnaud
authors.affiliation: ISP, INRA, Université François Rabelais de Tours, UMR1282, Nouzilly, France.
authors.forename: Axel
authors.initials: A
authors.lastname: Cloeckaert
authors.affiliation: ISP, INRA, Université François Rabelais de Tours, UMR1282, Nouzilly, France.
authors.forename: Michel S
authors.initials: MS
authors.lastname: Zygmunt
authors.affiliation: Animal &Plant Health Agency, Addlestone, United Kingdom.
authors.forename: Adrian M
authors.initials: AM
authors.lastname: Whatmore
authors.affiliation: Friedrich-Loeffler-Institut, German National Reference Laboratory for Animal Brucellosis, Jena, Germany.
authors.forename: Falk
authors.initials: F
authors.lastname: Melzer
authors.affiliation: University of New Hampshire, Department of Molecular, Cellular, and Biomedical Sciences, Durham, NH, USA.
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Drees
authors.affiliation: University of New Hampshire, Department of Molecular, Cellular, and Biomedical Sciences, Durham, NH, USA.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Foster
authors.affiliation: Biocomplexity Institute, Virginia Tech, Blacksburg, VA, USA.
authors.forename: Alice R
authors.initials: AR
authors.lastname: Wattam
authors.affiliation: Bundeswehr Institute of Microbiology and German Center for Infection Research (DZIF), Munich, Germany.
authors.forename: Holger C
authors.initials: HC
authors.lastname: Scholz
mesh_terms: D000818:Animals; D000836:Animals, Zoo; D001001:Anura; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D005075:Biological Evolution; D042021:Brucellaceae / Q000145:classification / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D002460:Cell Line; D005407:Flagella / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D015964:Gene Expression Regulation, Bacterial; D018740:Genetic Heterogeneity; D005858:Germany; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology / Q000662:veterinary*; D054884:Host-Pathogen Interactions; D008099:Liver / Q000382:microbiology; D008264:Macrophages / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D013154:Spleen / Q000382:microbiology; D013636:Tanzania
chemical_list: D001426:Bacterial Proteins