Catalase
Ornithine
decarboxylase
Citrate
utilization
Malonate
utilization
Indole
production
H2S
production
KCN
growth
D-adonitol
fermentation
C. amalonaticus
+
+
+
-
+
d
+
-
C. freundii
+
-
[+]
[-]
[-]
d
d
-
C. braakii
+
+
[+]
-
[-]
d
+
-
C. cronae
+
d
d
[+]
-
d
nd
d
C. europaeus
+
+
-
nd
-
+
nd
-
C. farmeri
+
+
-
-
+
-
+
-
C. gillenii
+
-
[-]
+
-
d
+
-
C. koseri (C. diversus)
+
+
+
+
+
-
-
+
C. murliniae
-
-
+
-
+
d
+
-
C. pasteurii
-
-
+
-
-
+
nd
-
C. portucalensis
-
-
+
 
-
+
nd
-
C. rodentium
+
+
-
+
-
-
-
-
C. sedlakii
+
+
[+]
+
[+]
d
+
-
C. telavivensis
+
nd
+
 
+
-
nd
-
C. werkmanii
[+]
-
+
+
-
+
+
-
C. youngae
[+]
-
[+]
-
[-]
d
+
-
Taxonomy
Morphology
Cultural characteristics
Biochemical characters
Ecology
Pathogenicity
References
Phylum Proteobacteria, Class Gammaproteobacteria, Order Enterobacterales, Family Enterobacteriaceae, Genus Citrobacter,
Citrobacter youngae
Brenner et al. 1993.

S
ynonym: Citrobacter genomospecies 5.
Gram-negative, straight rods, 1.0 x 2.0-6.0 μm, found singly or in pairs. Most strains
are motile by peritrichous flagella. Not encapsulated.
Colonies on nutrient agar are generally 2-4 mm in diameter, smooth, low convex,
moist, translucent or opaque, and gray with a shiny surface and entire edge.
Facultatively anaerobic. Incubation temperature 37 °C.
Isolated from food , animals and human stools, urine, and wounds.
Opportunistic pathogen.
  1. J. G. Holt et al., 1994. Facultatively Anaerobic Gram-Negative Rods. Subgroup 1. Family Enterobacteriaceae. In: Begey’s Manual of
    Determinative Bacteriology, 9th-edition, Williams & Wilkins, pp 175-189.
  2. Don J. Brenner and J.J. Farmer III, 2001. Family I. Enterobacteriaceae. In: Bergey’s Manual of Systematic Bacteriology, Second
    edition, Vol two, part B, George M. Garrity (Editor-in-Chief), pp 587-897.
  3. Werkman (C.H.) and Gillen (G.F.): Bacteria producing trimethylene glycol. Journal of Bacteriology,1932, 23,167-182
  4. Ewing(W.H.) and Davis (B.R.): Biochemical characterization of Citrobacter diversus (Burkey) Werkman and Gillen and designation
    of the neotype strain. Int. J. Syst. Bacteriol., 1972, 22, 12-18.
  5. M.P. STARR et al. (ed.), The procaryotes, a handbook on habitats, isolation, and identification of bacteria.Springer-Verlag, Berlin,
    1981, p. 1140-1147
  6. Abbot SL, Klebsiella, Enterobacter, Citrobacter, Serratia, Plesiomonas, and other Enterobacteriaceae. In: Murray PR, Baron EJ,
    Jorgensen JH, Pfaller MA, Yolken RH. Manual of clinical microbiology. 8th edition. Washington DC: American Society for
    Microbiology, 2003:684-700
  7. Don J. Brenner. Biochemical Identification of citrobacter Species Defined by DNA Hybridization and Description of Citrobacter
    gillenii sp. nov. (formerly C. genomospecies 10) and C. murliniae sp. nov. (formerly Citrobacter genomospecies 11), Journal of
    Clinical Microbiology Aug. 1999, p. 2619–2624, Vol. 37, No. 8.
  8. Adeolu M, Alnajar S, Naushad S, S Gupta R. Genome-based phylogeny and taxonomy of the 'Enterobacteriales': proposal for
    Enterobacterales ord. nov. divided into the families Enterobacteriaceae, Erwiniaceae fam. nov., Pectobacteriaceae fam. nov.,
    Yersiniaceae fam. nov., Hafniaceae fam. nov., Morganellaceae fam. nov., and Budviciaceae fam. nov. Int J Syst Evol Microbiol
    2016; 66:5575-5599.
  9. Oberhettinger P, Schule L, Marschal M, Bezdan D, Ossowski S, Dorfel D, Vogel W, Rossen JW, Willmann M, Peter S. Description
    of Citrobacter cronae sp. nov., isolated from human rectal swabs and stool samples. Int J Syst Evol Microbiol 2020; 70:2998-3003.
  10. Ribeiro TG, Clermont D, Branquinho R, Machado E, Peixe L, Brisse S. Citrobacter europaeus sp. nov., isolated from water and
    human faecal samples. Int J Syst Evol Microbiol 2017; 67:170-173.
  11. Clermont D, Motreff L, Passet V, Fernandez JC, Bizet C, Brisse S. Multilocus sequence analysis of the genus Citrobacter and
    description of Citrobacter pasteurii sp. nov. Int J Syst Evol Microbiol 2015; 65:1486-1490.
  12. Ribeiro TG, Goncalves BR, da Silva MS, Novais A, Machado E, Carrico JA, Peixe L. Citrobacter portucalensis sp. nov., isolated from
    an aquatic sample. Int J Syst Evol Microbiol 2017; 67:3513-3517.
  13. Ribeiro TG, Izdebski R, Urbanowicz P, Carmeli Y, Gniadkowski M, Peixe L. Citrobacter telavivum sp. nov. with chromosomal mcr-9
    from hospitalized patients. Eur J Clin Microbiol Infect Dis 2021; 40:123-131.
Positive results for methyl red, ONPG, nitrate reduction, Tartrate (Jordans), acid production from: glucose (with gas), L-arabinose,
maltose, D-mannitol, mannose
, D-sorbitol. L-rhamnose, trehalose and D-xylose.

Negative results fo oxidase, lysine decarboxylase, Voges-Proskauer, phenylalanine, gelatinase,  deoxyribonuclease, lipase, acid
production from: D-arabitol, erythritol, myo-inositol, melibiose,
and raffinose.

Variable results for fermentation of dulcitol and sucrose.
(c) Costin Stoica
Antibiogram
Encyclopedia
Culture media
Biochemical tests
Stainings
Images
Movies
Articles
Identification
Software
R E G N U M
PROKARYOTAE
Differential characters of the species:
Legend: +  positive 90-100%, - negative 90-100%, [+] positive 75-89%, [-] negative 75-89%, d positive 25-74%, nd not determined.
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Citrobacter youngae