Name: Yersinia frederiksenii Ursing et al. 1981

Category: Species

Proposed as: sp. nov.

Etymology: fre.de.rik.se’ni.i. N.L. gen. masc. n. frederiksenii, of Frederiksen, named after the Danish microbiologist Wilhelm Frederiksen, who made a substantial contribution to the study of the genus Yersinia

Pronunciation, gender: fre-de-rik-SE-ni-i, feminine

Type strain: 6175; ATCC 33641; CCUG 11293; CIP 80.29; DSM 18490; NCTC 11470

See detailed strain information at

Conduct genome-based taxonomy at

16S rRNA gene: AF366379 Analyse FASTA

Effective publication: Ursing J, Brenner DJ, Bercovier H, Fanning GR, Steigerwalt AG, Brault J, Mollaret HH. Yersinia frederiksenii: a new species of Enterobacteriaceae composed of rhamnose-positive strains (formerly called atypical Yersinia enterocolitica or Yersinia enterocolitica-like). Curr. Microbiol. 1980; 4:213-217.

IJSEM list: Anonymous. Validation list no. 6. Validation of publication of new names and new combinations previously effectively published outside the IJSB. Int J Syst Bacteriol 1981; 31:215-218.

Nomenclatural status: validly published under the ICNP

Taxonomic status: correct name (and explicitly recommended for medical use)

Risk group: 2

• Notes:
  • 🧬 The phylogenomic assignment score of this taxon is 0.07161 (N = 4).
  • 😷 The risk group for Belgium has been imported on 2024-02-05. The full classification is: risk group = 2, note = "human pathogen". — The risk group for Canada has been imported on 2024-02-27. The full classification is: risk group = 2, note = "Animal classification RG: 1 - Security sensitive biological agent: No - Terrestrial animal pathogen under Canadian Food Inspection Agency authority: No - Containment level: Containment Level 2". — The risk group for Swiss Confederation has been imported on 2024-02-01. The full classification is: risk group = 2. — The risk group for Germany has been imported on 2023-10-29. The full classification is: risk group = 2, note = "Z". — If in doubt, use the risk group given in the regulations for your country and, if these are not available, use the risk group given in the catalogue of the culture collection from which you have obtained or intend to obtain the strain.
  • 🎓 Name mentioned 72 times in PubMed until 2025-06-04.
  • 🪓 Organisms assigned to this species have previously been classified as Yersinia enterocolitica (Schleifstein and Coleman 1939) Frederiksen 1964 (Approved Lists 1980). Publication: Frederiksen W. A study of some Yersinia pseudotuberculosis-like bacteria (Bacterium enterocoliticum and Pasteurella X). Proceedings of the XIV Scandinavian Congress of Pathology and Microbiology, Oslo 1964. Norwegian Universities Press, Oslo, 1964. Skerman VBD, McGowan V, Sneath PHA. Approved lists of bacterial names. Int J Syst Bacteriol 1980; 30:225-420.
  • 🫡 This name is on the List of Recommended Names for bacteria of medical importance (LoRN) as the name to be applied to this species. The name is on LoRN because of the recorded risk group of the species itself. This name is not taxonomically suspended any more in favour of Yersinia enterocolitica (Schleifstein and Coleman 1939) Frederiksen 1964 (Approved Lists 1980). Publication: Frederiksen W. A study of some Yersinia pseudotuberculosis-like bacteria (Bacterium enterocoliticum and Pasteurella X). Proceedings of the XIV Scandinavian Congress of Pathology and Microbiology, Oslo 1964. Norwegian Universities Press, Oslo, 1964. Skerman VBD, McGowan V, Sneath PHA. Approved lists of bacterial names. Int J Syst Bacteriol 1980; 30:225-420.
  • 🧍 According to Bartlett et al. (2022), this species is an established human pathogen. Publication: Bartlett A, Padfield D, Lear L, Bendall R, Vos M. A comprehensive list of bacterial pathogens infecting humans. Microbiology (Reading) 2022; 168:0.

Parent taxon: Yersinia van Loghem 1944 (Approved Lists 1980)

Assigned by: Ursing J, Brenner DJ, Bercovier H, Fanning GR, Steigerwalt AG, Brault J, Mollaret HH. Yersinia frederiksenii: a new species of Enterobacteriaceae composed of rhamnose-positive strains (formerly called atypical Yersinia enterocolitica or Yersinia enterocolitica-like). Curr. Microbiol. 1980; 4:213-217.

Linking: To permanently link to this page, use https://lpsn.dsmz.de/species/yersinia-frederikseniiCopy to clipboardLink copied to clipboard

Record number: 785222