1887

Abstract

The organism designated the SF agent was originally isolated in Japan in 1962 from metacercaria parasitic on gray mullet fish. The SF agent resembles members of the genus morphologically and exhibits weak antigenic cross-reactivity with . This organism causes mild clinical signs in dogs, but severe splenomegaly and lymphadenopathy in mice. This suggests that the SF agent may be similar to either , an intracellular parasite of a fluke and the cause of salmon poisoning disease in dogs, or , the causative agent of human sennetsu ehrlichiosis in Japan and Malaysia. In order to determine the phylogenetic relationship between the SF agent and other ehrlichial species, the 16S rRNA gene was amplified by the PCR and sequenced. The SF agent sequence was most closely related to the sequences of (level of sequence similarity, 99.1%), the causative agent of Potomac horse fever, and (level of sequence similarity, 98.7%). The next most similar sequence was that of , but the level of sequence similarity was only 93.7%. , the SF agent, and formed a distinct cluster that was separated from all other ehrlichial species. As determined by immunofluorescence labeling, antiserum against the SF agent cross-reacted strongly with , and . When three genetically distinct ehrlichial isolates obtained from horses with Potomac horse fever were compared with the SF agent, we found that the SF agent was most closely related to Ohio isolate 081, followed by Illinois (T = type strain) and a Kentucky isolate. We observed strong antigenic cross-reactivities and similarities in Western blot (immunoblot) reaction profiles when we compared the SF agent, , and however, weaker antigenic cross-reactivity was observed when the SF agent and were compared. Our results indicate that the SF agent is antigenically more closely related to and than to . The biological and antigenic characteristics and the 16S rRNA sequence data suggest that the SF agent is a new species that belongs to the genus .

Loading

Article metrics loading...

/content/journal/ijsem/10.1099/00207713-46-1-149
1996-01-01
2024-06-23
Loading full text...

Full text loading...

/deliver/fulltext/ijsem/46/1/ijs-46-1-149.html?itemId=/content/journal/ijsem/10.1099/00207713-46-1-149&mimeType=html&fmt=ahah

References

  1. Anderson B. E., Dawson J. E., Jones D. C., Wilson K. H. 1991; Ehrlichia chaffeensis, a new species associated with human ehrlichiosis. J. Clin. Microbiol 29:2838–2842
    [Google Scholar]
  2. Anderson B. E., Greene C. E., Jones D. C., Dawson J. E. 1992; Ehrlichia ewingii sp. nov., the etiologic agent of canine granulocytic ehrlichiosis. Int. J. Syst. Bacteriol 42:299–302
    [Google Scholar]
  3. Chaichanasiriwithaya W., Rikihisa Y., Yamamoto S., Reed S. M., Crawford T. B., Perryman L. E., Palmer G. H. 1994; Antigenic, morphologic, and molecular characterization of new Ehrlichia nsticii isolates. J. Clin. Microbiol 38:3026–3033
    [Google Scholar]
  4. Chen S. M., Dumler J. S., Bakken J. S., Walker D. H. 1994; Identification of a granulocytotropic Ehrlichia species as the etiologic agent of human disease. J. Clin. Microbiol 32:589–595
    [Google Scholar]
  5. Felsenstein J. 1989; PHYLIP–phylogeny inference package (version 3.3). Cladistics 5:164–166
    [Google Scholar]
  6. Fukuda T., Sasahara T., Kitao T. 1972; Studies on the causative agent of “Hyuganetsu”, disease. X, Vector. J. Jpn. Assoc. Infect. Dis 36:235–241 In Japanese
    [Google Scholar]
  7. Fukuda T., Sasahara T., Kitao T. 1973; Studies on the causative agent of “Hyuganetsu”, disease. XI. Characteristics of rickettsia-like organism isolated from metacercaria of Stellantchasmus falcatus parasitic in grey mullet. J. Jpn. Assoc. Infect. Dis 47:474–482 In Japanese
    [Google Scholar]
  8. Fukuda T., Yamamoto S. 1979; Antigenic analysis and ultrastructure of the rickettsia-like organism isolated from Stellantchasmus falcatus. J. Jpn. Assoc. Infect. Dis 53:713–716 In Japanese
    [Google Scholar]
  9. Fukuda T., Yamamoto S. 1981; Neorickettsia-Iike organism isolated from metacercaria of a fluke, Stellantchasmus falcatus. Jpn. J. Med. Sci. Biol 34:103–107
    [Google Scholar]
  10. Pretzman C., Ralph D., Stothard D. R., Fuerst P. A., Rikihisa Y. 1995; 16S rRNA gene sequence of Neorickettsia helminthoecal phylogenetic alignment with members of the genus Ehrlichia. Int. J. Syst. bacteriology 45:207–211
    [Google Scholar]
  11. Rikihisa Y. 1991; The tribe Ehrlichieae and ehrlichial diseases. Clin. Microbiol. Rev 4:286–308
    [Google Scholar]
  12. Rikihisa Y. 1991; Cross-reacting antigens between Neorickettsia helminthoeca and Ehrlichia species, shown by immunofluorescence and Western immunoblotting. J. Clin. Microbiol 29:2024–2029
    [Google Scholar]
  13. Rikihisa Y., Ewing S. A., Fox J. C., Siregar A. G., Pasaribu F. H., Malole M. B. 1992; Analysis of Ehrlichia canis and a canine granulocyte Ehrlichia infection. J. Clin. Microbiol 30:143–148
    [Google Scholar]
  14. Ristic M., HuxolL D. 1984 Tribe II. Ehrlichieae,. 704–711 Krieg N. R., Holt J. G.ed Bergey’s manual of systematic bacteriology 1 The Williams & Wilkins Co.; Baltimore:
    [Google Scholar]
  15. Weisburg W. G., Dobson M. E., Samuel J. E., Dasch G. A., Mallavia L., Baca O., Mandelco L., Sechrest J. E., Weiss E., Woese C. R. 1989; Phylogenetic diversity of the rickettsiae. J. Bacteriol 171:4202–4206
    [Google Scholar]
  16. Wen B., Rikihisa Y., Fuerst P. A., Chaichanasiriwithaya W. 1995; Diversity of 16S rRNA genes of new Ehrlichia strains isolated from horses with clinical signs of Potomac horse fever. Int. J. Syst. Bacteriol 45:315–318
    [Google Scholar]
  17. Wen B., Rikihisa Y., Mott J., Fuerst P. A., Kawahara M., Suto C. 1995; Ehrlichia muris sp. nov., identified on the basis of 16S rRNA base sequences and serological and biological characteristics. Int. J. Syst. Bacteriol 45:250–254
    [Google Scholar]
  18. Woese C. R. 1987; Bacterial evolution. Microbiol. Rev 51:221–271
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/ijsem/10.1099/00207713-46-1-149
Loading
/content/journal/ijsem/10.1099/00207713-46-1-149
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error