Citrobacter

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Citrobacter
Citrobacter freundii
Citrobacter freundii
Scientific classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Gamma Proteobacteria
Order: Enterobacteriales
Family: Enterobacteriaceae
Genus: Citrobacter
Werkman and Gillen, 1932
Species

C. amalonaticus
C. braakii
C. farmeri
C. freundii
C. gillenii
C. intermedius
C. koseri aka C. diversus
C. murliniae
C. rodentium
C. sedlakii
C. werkmanii
C. youngae

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Citrobacter is a genus of Gram-negative coliform bacteria in the Enterobacteriaceae family. They are rarely the source of illnesses, except for infections of the urinary tract and infant meningitis and sepsis.[1][2]

Organism

Citrobacter freundi

  • Citrobacter freundi is a species of facultative. aerobic. Gram-negative bacilli of the Enterobacteriaceae family.[4] The bacteria are long rod-shaped with a typical length of 1–5 μm.[5] Most C. freundii cells are surrounded by several flagella used for locomotion, but a few are not mobile. It can be found in soil, water, sewage, food, and the intestinal tracts of animals and humans.[5] The Citrobacter genus was discovered in 1932 by Werkman and Gillen. Cultures of C. freundii were isolated and identified in the same year from soil extracts.[5]
  • As an opportunistic pathogen, C. freundii is responsible for a number of significant infections. It is known to be the cause of a number of nosocomial infections of the respiratory tract, urinary tract, blood, and many other normally sterile sites in patients.[6] C. freundii represents about 29% of all opportunistic infections.[6]
  • Surprisingly, this infectious microbe in humans plays a positive role in the environment. C. freundii is responsible for reducing nitrate to nitrite in the environment.[7] This conversion is an important and crucial stage in the nitrogen cycle. These bacteria also help in recycling nitrogen.[7]
  • C. freundii has also been investigated for biodegradation of tannic acid used in tanneries.[7]
  • For metabolism, C. freundii has an ability to grow on glycerol as the sole carbon and energy source. Within its cell, a bacterial microcompartment can be found, which is capable of processing propanediol.[8]


Antimicrobial regimen

  • Citrobacter freundii[9]
  • Citrobacter koseri[10]
  • Preferred regimen (1): Ceftriaxone 1-2 g IV q12-24h
  • Preferred regimen (2): Cefotaxime 1-2 g IV q6h
  • Preferred regimen (3): Cefepime 1-2 IV q8h
  • Alternative regimen (1): Ciprofloxacin 400 mg IV q12h or 500 mg PO q12h for UTI
  • Alternative regimen (2): Imipenem 1 g IV q6h
  • Alternative regimen (3): Doripenem 500 mg IV q8h
  • Alternative regimen (4): Meropenem 1-2 g IV q8h
  • Alternative regimen (5): Aztreonam 1-2 g IV q6h
  • Alternative regimen (6): TMP-SMX 5 mg/kg IV q6h or DS PO bid for UTI
  • Note: Usually Ampicillin resistant, but may be sensitive to first generation cephalosporins.

Gallery

References

  1. V. Drelichman (1985). "Bacteremias due to Citrobacter diversus and Citrobacter freundii. Incidence, risk factors, and clinical outcome". Archives of Internal Medicine 145 (10): 1808–1810. doi:10.1001/archinte.145.10.1808. PMID 3899035.
  2. Badger, J.D. (1999). "Citrobacter freundii Invades and Replicates in Human Brain Microvascular Endothelial Cells". Infection and Immunity 67 (8): 4208–15. PMID 10417193.
  3. L. E. Macaskie, R. M. Empson, A. K. Cheetham, C. P. Grey, A. J. Skarnulis (1992). "Uranium bioaccumulation by a Citrobacter sp. as a result of enzymically mediated growth of polycrystalline HUO2PO4". Science 257: 782-784. doi:10.1126/science.1496397.
  4. Citrobacter SPP.. Pathogen Safety Data Sheet — Infectious Substances. Public Health Agency of Canada (2012).
  5. 5.0 5.1 5.2 PMID 11269372 (PubMed)
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  6. 6.0 6.1 PMID 17224563 (PubMed)
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  7. 7.0 7.1 7.2 PMID 8983520 (PubMed)
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  8. PMID 21245529 (PubMed)
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  9. Bartlett, John (2012). Johns Hopkins ABX guide : diagnosis and treatment of infectious diseases. Burlington, MA: Jones and Bartlett Learning. ISBN 978-1449625580. 
  10. Bartlett, John (2012). Johns Hopkins ABX guide : diagnosis and treatment of infectious diseases. Burlington, MA: Jones and Bartlett Learning. ISBN 978-1449625580. 
  11. Public Health Image Library (PHIL).

External links

ca:Citrobacteri de:Citrobacter


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