Citrobacter sedlakii

Citrobacter sedlakii is a species of Gram-negative bacteria.[1] It has been described as causing human disease, but is generally found as a non-pathogenic organism in human stools.

Citrobacter sedlakii
Scientific classification
C. sedlakii
Binomial name
Citrobacter sedlakii
Brenner et al. 1993


C. sedlakii was originally isolated from human stool and wounds as strains of Citrobacter freundii.[1] However, in 1993 six strains of C. freundii were identified as a separate species based on DNA hybridization, and were named C. sedlakii to honor Czech microbiologist Jiri Sedlak.[1]


C. sedlakii is a rod-shaped gram-negative bacterium. It can be distinguished from other Citrobacter species by its ability to produce indole, arginine dihydrolase activity, and ornithine decarboxylase activity.[1]

Role in diseaseEdit

C. sedlakii was originally isolated from human stool and wounds and was suggested to be pathogenic in humans.[1] While some reports have described C. sedlakii as causing illness in humans, it is frequently found in stool and is not thought to be pathogenic in most cases.[2] C. sedlakii can express the O157 antigen which is commonly found on pathogenic E. coli, however this does not cause disease.[3]


  1. ^ a b c d e Brenner, D. J.; Grimont, P. A. D.; Steigerwalt, A. G.; Fanning, G. R.; Ageron, E.; Riddle, C. F. (1993). "Classification of Citrobacteria by DNA Hybridization: Designation of Citrobacter farmeri sp. nov., Citrobacter youngae sp. nov., Citrobacter braakii sp. nov., Citrobacter werkmanii sp. nov., Citrobacter sedlakii sp. nov., and Three Unnamed Citrobacter Genomospecies". International Journal of Systematic Bacteriology. 43 (4): 645–658. doi:10.1099/00207713-43-4-645. ISSN 0020-7713. PMID 8240948.
  2. ^ James Dyer; Karen C. Hayani; William M. Janda; Paul C. Schreckenberger (10 July 1997). "Citrobacter sedlakii Meningitis and Brain Abscess in a Premature Infant" (PDF). Journal of Clinical Microbiology. American Society for Microbiology. 35 (10): 2686–2688. PMC 230040. PMID 9316937. Archived (PDF) from the original on 20 December 2016. Retrieved 19 December 2016.
  3. ^ C.H. Park; E.A. Martin; E.L. White (27 January 1998). "Isolation of a Nonpathogenic Strain of Citrobacter sedlakii Which Expresses Escherichia coli O157 Antigen". Journal of Clinical Microbiology. American Society for Microbiology. 36 (5): 1408–1409. PMC 104838. PMID 9574715.

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