title: Comparison of the nucleotide sequences of 16S rRNA, 444 Ep-ank, and groESL heat shock operon genes in naturally occurring Ehrlichia equi and human granulocytic ehrlichiosis agent isolates from Northern California.
abstract: We examined 11 naturally occurring isolates of Ehrlichia equi in horses and two human granulocytic ehrlichiosis agent isolates in California for sequence diversity in three genes. Ehrlichia equi isolates were from Sierra (n = 6), Mendocino (n = 3), Sonoma (n = 1), and Marin (n = 1) counties, and human granulocytic ehrlichiosis (HGE) agent isolates were obtained from Humboldt county. PCR with specific primers for 16S rRNA, 444 Ep-ank and groESL heat shock operon genes successfully produced amplicons for all 13 clinical samples. The 444 Ep-ank gene of the HGE agent and E. equi isolates from northern California is different from the eastern U.S. isolates BDS and USG3. The translated amino acid sequence of the groESL heat shock operon gene fragment is identical among E. equi, the HGE agent, and E. phagocytophila, with the exception of the northern Californian equine CASOLJ isolate. Microheterogeneity was observed in the 16S rRNA gene sequences of HGE agent and E. equi isolates from northern California. These results suggest that E. equi and the HGE agent found in California are similar or identical but may differ from the isolates of equine and human origin found in the eastern United States.
authors.affiliation: Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California 95616, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Chae
authors.forename: J E
authors.initials: JE
authors.lastname: Foley
authors.forename: J S
authors.initials: JS
authors.lastname: Dumler
authors.forename: J E
authors.initials: JE
authors.lastname: Madigan
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D002140:California; D018833:Chaperonins / Q000235:genetics*; D004536:Ehrlichia / Q000235:genetics* / Q000302:isolation & purification; D016873:Ehrlichiosis / Q000382:microbiology* / Q000662:veterinary; D005260:Female; D005798:Genes, Bacterial; D020459:Genes, rRNA; D006734:Horse Diseases / Q000382:microbiology*; D006736:Horses; D006801:Humans; D008969:Molecular Sequence Data; D009876:Operon; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; C097970:GroESL protein, Bacteria; D012336:RNA, Ribosomal, 16S; D018833:Chaperonins