title: Rickettsia felis from cat fleas: isolation and culture in a tick-derived cell line.
abstract: Rickettsia felis, the etiologic agent of spotted fever, is maintained in cat fleas by vertical transmission and resembles other tick-borne spotted fever group rickettsiae. In the present study, we utilized an Ixodes scapularis-derived tick cell line, ISE6, to achieve isolation and propagation of R. felis. A cytopathic effect of increased vacuolization was commonly observed in R. felis-infected cells, while lysis of host cells was not evident despite large numbers of rickettsiae. Electron microscopy identified rickettsia-like organisms in ISE6 cells, and sequence analyses of portions of the citrate synthase (gltA), 16S rRNA, Rickettsia genus-specific 17-kDa antigen, and spotted fever group-specific outer membrane protein A (ompA) genes and, notably, R. felis conjugative plasmids indicate that this cultivatable strain (LSU) was R. felis. Establishment of R. felis (LSU) in a tick-derived cell line provides an alternative and promising system for the expansion of studies investigating the interactions between R. felis and arthropod hosts.
authors.affiliation: Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, SVM-3213, Baton Rouge, LA 70803, USA.
authors.forename: Walairat
authors.initials: W
authors.lastname: Pornwiroon
authors.forename: Susan S
authors.initials: SS
authors.lastname: Pourciau
authors.forename: Lane D
authors.initials: LD
authors.lastname: Foil
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Macaluso
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D002415:Cats; D002460:Cell Line; D018884:Ixodes / Q000382:microbiology*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D041161:Rickettsia felis / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification*; D017422:Sequence Analysis, DNA; D005423:Siphonaptera / Q000382:microbiology*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C078167:OMPA outer membrane proteins