Name: Curtobacterium flaccumfaciens (Hedges 1922) Collins and Jones 1984

Category: Species

Proposed as: comb. nov.

Basonym: "Bacterium flaccumfaciens" Hedges 1922

Etymology: flac.cum.fa.ci.ens. L. adj. flaccus, flabby; L. pres. part. faciens, making; N.L. neut. part. adj. flaccumfaciens, wilt-making

Gender: neuter

Type strain: CIP 107085; ICMP 2584; JCM 9670; LMG 3645; NCPPB 1446

Conduct genome-based taxonomy at

16S rRNA gene: AJ312209 Analyse FASTA

Effective publication: Collins MD, Jones D. Reclassification of Corynebacterium flaccumfaciens, Corynebacterium betae, Corynebacterium oortii and Corynebacterium poinsettiae in the genus Curtobacterium, as Curtobacterium flaccumfaciens comb. nov. J. Gen. Microbiol. 1983; 129:3545-3548.

IJSEM list: Anonymous. Validation list no. 14. Validation of publication of new names and new combinations previously effectively published outside the IJSB. Int J Syst Bacteriol 1984; 34:270-271.

Nomenclatural status: validly published under the ICNP

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

Risk group: 2

• Synonyms:

  • Name	Kind
    "Bacterium flaccumfaciens" Hedges 1922	homotypic synonym, not validly published, basonym of name in Approved Lists
    Corynebacterium flaccumfaciens (Hedges 1922) Dowson 1942 (Approved Lists 1980)	homotypic synonym, validly published under the ICNP
    Corynebacterium oortii Saaltink and Maas Geesteranus 1969 (Approved Lists 1980)	heterotypic synonym, validly published under the ICNP
    Corynebacterium betae Keyworth et al. 1956 (Approved Lists 1980)	heterotypic synonym, validly published under the ICNP
    Corynebacterium flaccumfaciens subsp. betae (Keyworth et al. 1956) Carlson and Vidaver 1982	heterotypic synonym, validly published under the ICNP, distinct rank
    Corynebacterium flaccumfaciens subsp. oortii (Saaltink and Maas Geesteranus 1969) Carlson and Vidaver 1982	heterotypic synonym, validly published under the ICNP, distinct rank
    Corynebacterium flaccumfaciens subsp. poinsettiae (Starr and Pirone 1942) Carlson and Vidaver 1982	heterotypic synonym, validly published under the ICNP, distinct rank
    "Curtobacterium poinsettiae" (Starr and Pirone 1942) Osdaghi et al. 2024	heterotypic synonym, not validly published
    Curtobacterium aurantiacum Osdaghi et al. 2025	heterotypic synonym, validly published under the ICNP
    "Phytomonas poinsettiae" Starr and Pirone 1942	heterotypic synonym, not validly published, basonym of name in Approved Lists
    Corynebacterium poinsettiae (Starr and Pirone 1942) Burkholder 1948 (Approved Lists 1980)	heterotypic synonym, validly published under the ICNP

• Emendations:
  • Osdaghi et al. 2024 Osdaghi E, Taghavi SM, Hamidizade M, Kariminejhad M, Fazliarab A, Hajian Maleki H, Baeyen S, Taghouti G, Jacques MA, Van Vaerenbergh J, et al. Multiphasic investigations imply transfer of orange-/red-pigmented strains of the bean pathogen Curtobacterium flaccumfaciens pv. flaccumfaciens to a new species as C. aurantiacum sp. nov., elevation of the poinsettia pathogen C. flaccumfaciens pv. poinsettiae to the species level as C. Poinsettiae sp. nov., and synonymy of C. albidum with C. citreum. Syst Appl Microbiol 2024; 47:126489. Oren A, Göker M. List of changes in taxonomic opinion no. 40. Notification of changes in taxonomic opinion previously published outside the IJSEM. Int J Syst Evol Microbiol 2024; 74:6482.
    Notes:
    • 😢 The terminology used by the authors is in line with many other taxonomic studies and does not negatively affect their main results; some improvements may nevertheless be possible. The phrase "valid name" is misleading. Whether taxa can have "members" is debatable. See the LPSN phylogeny page for details.

• Notes:
  • ⏰ According to Collins and Jones (1983), this species is an earlier heterotypic synonym of "Phytomonas poinsettiae" Starr and Pirone 1942. Publication: Collins MD, Jones D. Reclassification of Corynebacterium flaccumfaciens, Corynebacterium betae, Corynebacterium oortii and Corynebacterium poinsettiae in the genus Curtobacterium, as Curtobacterium flaccumfaciens comb. nov. J. Gen. Microbiol. 1983; 129:3545-3548.
  • ⏰ According to Collins and Jones (1983), this species is an earlier heterotypic synonym of Corynebacterium betae Keyworth et al. 1956 (Approved Lists 1980). Publication: Collins MD, Jones D. Reclassification of Corynebacterium flaccumfaciens, Corynebacterium betae, Corynebacterium oortii and Corynebacterium poinsettiae in the genus Curtobacterium, as Curtobacterium flaccumfaciens comb. nov. J. Gen. Microbiol. 1983; 129:3545-3548.
  • ⏰ According to Collins and Jones (1983), this species is an earlier heterotypic synonym of Corynebacterium oortii Saaltink and Maas Geesteranus 1969 (Approved Lists 1980). Publication: Collins MD, Jones D. Reclassification of Corynebacterium flaccumfaciens, Corynebacterium betae, Corynebacterium oortii and Corynebacterium poinsettiae in the genus Curtobacterium, as Curtobacterium flaccumfaciens comb. nov. J. Gen. Microbiol. 1983; 129:3545-3548.
  • ⏰ According to Collins and Jones (1983), this species is an earlier heterotypic synonym of Corynebacterium poinsettiae (Starr and Pirone 1942) Burkholder 1948 (Approved Lists 1980). Publication: Collins MD, Jones D. Reclassification of Corynebacterium flaccumfaciens, Corynebacterium betae, Corynebacterium oortii and Corynebacterium poinsettiae in the genus Curtobacterium, as Curtobacterium flaccumfaciens comb. nov. J. Gen. Microbiol. 1983; 129:3545-3548.
  • ⏰ According to Collins and Jones (1983), this species is an earlier heterotypic synonym of "Curtobacterium poinsettiae" (Starr and Pirone 1942) Osdaghi et al. 2024. Publication: Collins MD, Jones D. Reclassification of Corynebacterium flaccumfaciens, Corynebacterium betae, Corynebacterium oortii and Corynebacterium poinsettiae in the genus Curtobacterium, as Curtobacterium flaccumfaciens comb. nov. J. Gen. Microbiol. 1983; 129:3545-3548.
  • ⏰ According to Committee (2025), this species is an earlier heterotypic synonym of Curtobacterium aurantiacum Osdaghi et al. 2025. Publication: Committee AH. Mitigating changes in prokaryotic nomenclature: Definitions and Workflow. Zenodo 2025; 2025:15320329.
  • 😷 The risk group for Belgium has been imported on 2024-02-01. The full classification is: risk group = 1, note = "pv. oortii: 1 plant pathogen - biological class of risk plant: 2; pv. betae: 1 plant pathogen - biological class of risk plant: 2". — The risk group for Swiss Confederation has been imported on 2024-02-01. The full classification is: risk group = 2, note = "PP QUA". — The risk group for Germany has been imported on 2023-10-29. The full classification is: risk group = 1, note = "default: 1 p2; pv. ilicis: 1 p2; pv. oortii: 1 p2; pv. betae: 1 p2; pv. poinsettiae: 1 p2". — 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 67 times in PubMed until 2024-03-27.
  • 🙆 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 retained (and recommended for medical use. This will change in the future) instead of Curtobacterium aurantiacum Osdaghi et al. 2025. Publication: Osdaghi E, Taghavi SM, Hamidizade M, Kariminejhad M, Fazliarab A, Hajian Maleki H, Baeyen S, Taghouti G, Jacques MA, Van Vaerenbergh J, et al. Multiphasic investigations imply transfer of orange-/red-pigmented strains of the bean pathogen Curtobacterium flaccumfaciens pv. flaccumfaciens to a new species as C. aurantiacum sp. nov., elevation of the poinsettia pathogen C. flaccumfaciens pv. poinsettiae to the species level as C. Poinsettiae sp. nov., and synonymy of C. albidum with C. citreum. Syst Appl Microbiol 2024; 47:126489. Oren A, Göker M. Validation list no. 222. List of new names and new combinations previously effectively, but not validly, published. Int J Syst Evol Microbiol 2025; 75:6640.
  • 🧍 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 2022; 168:0.
  • 🧍 Plant pathogenic according to Bull et al. (2007). Publication: Bull CT, De Boer SH, Denny TP, Firrao G, Fischer Le Saux M, Saddler GS, Scortichini M, Stead DE, Takikawa Y. Comprehensive list of names of plant pathogenic bacteria, 1980-2007. Journal of Plant Pathology 2010; 92:551-592.

Parent taxon: Curtobacterium Yamada and Komagata 1972 (Approved Lists 1980)

Assigned by: Collins MD, Jones D. Reclassification of Corynebacterium flaccumfaciens, Corynebacterium betae, Corynebacterium oortii and Corynebacterium poinsettiae in the genus Curtobacterium, as Curtobacterium flaccumfaciens comb. nov. J. Gen. Microbiol. 1983; 129:3545-3548.

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Record number: 775326