title: Rhodococcus equi: the many facets of a pathogenic actinomycete.
abstract: Rhodococcus equi is a soil-dwelling pathogenic actinomycete that causes pulmonary and extrapulmonary pyogranulomatous infections in a variety of animal species and people. Young foals are particularly susceptible and develop a life-threatening pneumonic disease that is endemic at many horse-breeding farms worldwide. R. equi is a facultative intracellular parasite of macrophages that replicates within a modified phagocytic vacuole. Its pathogenicity depends on a virulence plasmid that promotes intracellular survival by preventing phagosome-lysosome fusion. Species-specific tropism of R. equi for horses, pigs and cattle appears to be determined by host-adapted virulence plasmid types. Molecular epidemiological studies of these plasmids suggest that human R. equi infection is zoonotic. Analysis of the recently determined R. equi genome sequence has identified additional virulence determinants on the bacterial chromosome. This review summarizes our current understanding of the clinical aspects, biology, pathogenesis and immunity of this fascinating microbe with plasmid-governed infectivity.
authors.affiliation: Microbial Pathogenesis Unit, School of Biomedical Sciences and Edinburgh Infectious Diseases, University of Edinburgh, Edinburgh EH9 3JT, UK; Grupo de Patogenómica Bacteriana, Facultad de Veterinaria, Universidad de León, 24071 León, Spain. Electronic address: v.boland@ed.ac.uk.
authors.forename: José A
authors.initials: JA
authors.lastname: Vázquez-Boland
authors.forename: Steeve
authors.initials: S
authors.lastname: Giguère
authors.forename: Alexia
authors.initials: A
authors.lastname: Hapeshi
authors.forename: Iain
authors.initials: I
authors.lastname: MacArthur
authors.forename: Elisa
authors.initials: E
authors.lastname: Anastasi
authors.forename: Ana
authors.initials: A
authors.lastname: Valero-Rello
mesh_terms: D000193:Actinomycetales Infections / Q000382:microbiology / Q000473:pathology / Q000635:transmission / Q000662:veterinary*; D000818:Animals; D006734:Horse Diseases / Q000382:microbiology* / Q000473:pathology* / Q000635:transmission; D006736:Horses; D058507:Host Specificity; D006801:Humans; D010587:Phagocytosis / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D016929:Rhodococcus equi / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*
keywords: Foal rhodococcosis; Pathogenic actinomycetes; Rhodococcal pneumonia; Rhodococcus equi