The genome sequence of Rickettsia felis identifies the first putative conjugative plasmid in an obligate intracellular parasite

PLoS Biol. 2005 Aug;3(8):e248. doi: 10.1371/journal.pbio.0030248. Epub 2005 Jul 5.


We sequenced the genome of Rickettsia felis, a flea-associated obligate intracellular alpha-proteobacterium causing spotted fever in humans. Besides a circular chromosome of 1,485,148 bp, R. felis exhibits the first putative conjugative plasmid identified among obligate intracellular bacteria. This plasmid is found in a short (39,263 bp) and a long (62,829 bp) form. R. felis contrasts with previously sequenced Rickettsia in terms of many other features, including a number of transposases, several chromosomal toxin-antitoxin genes, many more spoT genes, and a very large number of ankyrin- and tetratricopeptide-motif-containing genes. Host-invasion-related genes for patatin and RickA were found. Several phenotypes predicted from genome analysis were experimentally tested: conjugative pili and mating were observed, as well as beta-lactamase activity, actin-polymerization-driven mobility, and hemolytic properties. Our study demonstrates that complete genome sequencing is the fastest approach to reveal phenotypic characters of recently cultured obligate intracellular bacteria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acclimatization
  • Antigens, Surface / analysis
  • Antigens, Surface / classification
  • Chromosome Mapping
  • DNA, Bacterial / genetics
  • Genes, Bacterial
  • Genome, Bacterial*
  • Genomics
  • Microscopy, Electron, Transmission
  • Molecular Sequence Data
  • Open Reading Frames
  • Phenotype
  • Plasmids / genetics*
  • Plasmids / isolation & purification
  • Rickettsia felis / genetics*
  • Rickettsia felis / pathogenicity
  • Rickettsia felis / ultrastructure
  • Sequence Homology, Nucleic Acid


  • Antigens, Surface
  • DNA, Bacterial

Associated data

  • GENBANK/CP000053
  • GENBANK/CP000054
  • GENBANK/CP000055
  • PDB/1VJ7