Name: Haemophilus ducreyi (Neveu-Lemaire 1921) Bergey et al. 1923 (Approved Lists 1980)

Category: Species

Proposed as: comb. nov.

Basonym: "Coccobacillus ducreyi" Neveu-Lemaire 1921

Etymology: du.crey’i. N.L. gen. masc. n. ducreyi, of Ducrey, named after Ducrey, the bacteriologist who first isolated this organism

Pronunciation (Latin), gender: … du-KREY-i, masculine

Type strain: ATCC 33940; CCUG 4438; CIP 54.2; DSM 8925; NCTC 10945

See detailed strain information at

Conduct genome-based taxonomy at

16S rRNA gene: M63900 Analyse FASTA

Effective publication: Bergey DH, Harrison FC, Breed RS, Hammer BW, Huntoon FM. Bergey's Manual of Determinative Bacteriology, 1st ed. The Williams & Wilkins Co, Baltimore, 1923.

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
    "Coccobacillus ducreyi" Neveu-Lemaire 1921	homotypic synonym, not validly published, basonym of name in Approved Lists
    "Pseudactinobacillus ducreyi" (Neveu-Lemaire 1921) Segui et al. 2026	homotypic synonym, not validly published

• Notes:
  • 🧬 The phylogenomic assignment score of this taxon is -0.10347 (N = 30).
  • 😷 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. — The risk group for France has been imported on 2024-08-30. The full classification is: risk group = 2. — The risk group for Sweden has been imported on 2024-02-05. 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". — The risk group for United Kingdom has been imported on 2024-01-31. The full classification is: risk group = 2. — The risk group for United States has been imported on 2024-02-09. The full classification is: risk group = 2. — 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 824 times in PubMed until 2025-06-04.
  • 🙆 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. 🇬🇧
  • 🧍 Haemophilus ducreyi has for long been recognized to be only distantly related to the type species of the genus Haemophilus. The Subcommittee on the taxonomy of Pasteurellaceae proposed to conduct a collaborative taxonomic investigation with the aim of proposing a new genus that would include Haemophilus ducreyi. Publication: Christensen H, Kuhnert P. International Committee on Systematics of Prokaryotes. Subcommittee on the taxonomy of Pasteurellaceae: minutes of the meetings, 25 August 2011, Elsinore, Denmark. Int J Syst Evol Microbiol 2012; 62:257-258. 🇨🇭

Parent taxon: Haemophilus corrig. Winslow et al. 1917 (Approved Lists 1980)

Assigned by: Bergey DH, Harrison FC, Breed RS, Hammer BW, Huntoon FM. Bergey's Manual of Determinative Bacteriology, 1st ed. The Williams & Wilkins Co, Baltimore, 1923.

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Record number: 776643