Name: Citrobacter freundii (Braak 1928) Werkman and Gillen 1932 (Approved Lists 1980)

Category: Species

Proposed as: comb. nov.

Basonym: "Bacterium freundii" Braak 1928

Etymology: freun’di.i. N.L. gen. masc. n. freundii, of Freund, named after A. Freund, the bacteriologist who first observed that trimethylene glycol was a product of fermentation

Pronunciation (Latin), gender: ki-tro-BAK-ter FRE͡UN-di-i, masculine

Type strain: ATCC 8090; CCUG 418; CIP 57.32; DSM 30039; HAMBI 1695; IFO 12681; JCM 1657; LMG 3246; NBIMCC 3731; NBRC 12681; NCAIM B.01468; NCTC 9750; NRRL B-2643

See detailed strain information at

Conduct genome-based taxonomy at

16S rRNA gene: KM515969 Analyse FASTA

Effective publication: Werkman CH, Gillen GF. Bacteria Producing Trimethylene Glycol. J Bacteriol 1932; 23:167-182.

IJSEM list: Skerman VBD, McGowan V, Sneath PHA. Approved lists of bacterial names. Int J Syst Bacteriol 1980; 30:225-420.

Nomenclatural status: validly published under the ICNP

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

Risk group: 2

• Synonyms:

  • Name	Kind
    "Bethesda ballerupensis" Kauffmann and Edwards 1952	heterotypic synonym, not validly published
    "Bacterium freundii" Braak 1928	homotypic synonym, not validly published, basonym of name in Approved Lists

• Notes:
  • 🥇 Nomenclatural type of the genus Citrobacter Werkman and Gillen 1932 (Approved Lists 1980). Publication: Werkman CH, Gillen GF. Bacteria Producing Trimethylene Glycol. J Bacteriol 1932; 23:167-182.
  • ⏰ According to Cowan (1956), this species is an earlier heterotypic synonym of "Bethesda ballerupensis" Kauffmann and Edwards 1952. Publication: Cowan ST. Taxonomic rank of Enterobacteriaceae groups. J Gen Microbiol 1956; 15:345-358.
  • 😷 The risk group for Canada has been imported on 2024-02-27. The full classification is: risk group = 2, note = "Animal classification RG: 2 - 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 2026-08-13. The full classification is: risk group = 2. — The risk group for Taiwan has been imported on 2024-11-03. The full classification is: risk group = 2, note = "P650 = v". — 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 2582 times in PubMed until 2026-06-11.
  • 🙆 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.
  • 🧍 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. 🇬🇧
  • 🧍 "Salmonella ballerup" Kauffmann and Møller 1940 (= "Salmonella hormaechei" Monteverde 1944 = the Ballerup group of bacteria = the Bethesda group of bacteria) is presently classified in Citrobacter freundii (Braak 1928) Werkman and Gillen 1932. Publication: Sakazaki R. Genus IV. Citrobacter Werkman and Gillen 1932, 173AL. In: Krieg NR, Holt JG (eds), Bergey's Manual of Systematic Bacteriology, first edition, vol. 1, The Williams & Wilkins Co., Baltimore, 1984, p. 458-461. 🇺🇸

Parent taxon: Citrobacter Werkman and Gillen 1932 (Approved Lists 1980)

Assigned by: Werkman CH, Gillen GF. Bacteria Producing Trimethylene Glycol. J Bacteriol 1932; 23:167-182.

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Record number: 774747