title: A real-time impedance based method to assess Rhodococcus equi virulence.
abstract: Rhodococcus equi is a facultative intracellular pathogen of macrophages and the causative agent of foal pneumonia. R. equi virulence is usually assessed by analyzing intracellular growth in macrophages by enumeration of bacteria following cell lysis, which is time consuming and does not allow for a high throughput analysis. This paper describes the use of an impedance based real-time method to characterize proliferation of R. equi in macrophages, using virulent and attenuated strains lacking the vapA gene or virulence plasmid. Image analysis suggested that the time-dependent cell response profile (TCRP) is governed by cell size and roundness as well as cytoxicity of infecting R. equi strains. The amplitude and inflection point of the resulting TCRP were dependent on the multiplicity of infection as well as virulence of the infecting strain, thus distinguishing between virulent and attenuated strains.
authors.affiliation: UCD School of Biomolecular and Biomedical Science and Conway Institute, University College Dublin, Dublin, Ireland.
authors.forename: Aleksandra A
authors.initials: AA
authors.lastname: Miranda-CasoLuengo
authors.forename: Raúl
authors.initials: R
authors.lastname: Miranda-CasoLuengo
authors.forename: Nora T
authors.initials: NT
authors.lastname: Lieggi
authors.forename: Haixia
authors.initials: H
authors.lastname: Luo
authors.forename: Jeremy C
authors.initials: JC
authors.lastname: Simpson
authors.forename: Wim G
authors.initials: WG
authors.lastname: Meijer
mesh_terms: D000193:Actinomycetales Infections / Q000382:microbiology* / Q000662:veterinary; D000818:Animals; D002460:Cell Line; D017097:Electric Impedance; D006736:Horses / Q000382:microbiology; D054884:Host-Pathogen Interactions; D006801:Humans; D008264:Macrophages / Q000166:cytology / Q000382:microbiology*; D051379:Mice; D009154:Mutation; D016929:Rhodococcus equi / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity* / Q000502:physiology
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