title: Rickettsia monteiroi sp. nov., infecting the tick Amblyomma incisum in Brazil.
abstract: Free-living adult Amblyomma incisum ticks were collected in an Atlantic rainforest area at Intervales State Park, State of São Paulo, Brazil. From an A. incisum specimen, rickettsiae were successfully isolated in Vero cell culture by the shell vial technique. Rickettsial isolation was confirmed by optical microscopy, transmission electron microscopy, and PCRs targeting portions of the rickettsial genes gltA, htrA, rrs, and sca1 on infected cells. Fragments of 1,089, 457, 1,362, and 443 nucleotides of the gltA, htrA, rrs, and sca1 genes, respectively, were sequenced. By BLAST analysis, the partial sequence of rrs of the A. incisum rickettsial isolate was closest to the corresponding sequence of Rickettsia bellii (99.1% similarity). The gltA partial sequence was closest to the corresponding sequences of "Candidatus Rickettsia tarasevichiae" (96.1% similarity) and Rickettsia canadensis (95.8% similarity). The htrA partial sequence was closest to the corresponding sequence of R. canadensis (89.8% similarity). The sca1 partial sequence was closest to the corresponding sequence of R. canadensis (95.2% similarity). Since our rickettsial isolate was genetically distinct from other Rickettsia species, we propose a new species designated Rickettsia monteiroi sp. nov. Phylogenetic analyses indicated that R. monteiroi belongs to the canadensis group within the genus Rickettsia, together with the species R. canadensis and "Candidatus R. tarasevichiae". Little or no antibody cross-reaction was observed between sera of R. monteiroi-inoculated guinea pigs and R. bellii-, Rickettsia rickettsii-, or R. canadensis-inoculated guinea pigs.
authors.affiliation: Faculty of Veterinary Medicine, University of Sao Paulo, Sao Paulo, SP, Brazil.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Pacheco
authors.forename: Jonas
authors.initials: J
authors.lastname: Moraes-Filho
authors.forename: Arlei
authors.initials: A
authors.lastname: Marcili
authors.forename: Leonardo J
authors.initials: LJ
authors.lastname: Richtzenhain
authors.forename: Matias P J
authors.initials: MP
authors.lastname: Szabó
authors.forename: Márcia H B
authors.initials: MH
authors.lastname: Catroxo
authors.forename: Donald H
authors.initials: DH
authors.lastname: Bouyer
authors.forename: Marcelo B
authors.initials: MB
authors.lastname: Labruna
mesh_terms: D000818:Animals; D001483:Base Sequence; D001938:Brazil; D002522:Chlorocebus aethiops; D004269:DNA, Bacterial / Q000235:genetics; D008853:Microscopy; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012281:Rickettsia / Q000145:classification* / Q000235:genetics*; D012282:Rickettsia Infections / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D013987:Ticks / Q000382:microbiology*; D014709:Vero Cells
chemical_list: D004269:DNA, Bacterial