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Citrobacter

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

Overview

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

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

References

  1. V. Drelichman; J. D. Band (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.; M.F. Stins; K.S. Kim (1999). “Citrobacter freundii Invades and Replicates in Human Brain Microvascular Endothelial Cells”. Infection and Immunity. 67 (8): 4208–15. PMC 96726. 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 (PMID 11269372)
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  6. 6.0 6.1 PMID 17224563 (PMID 17224563)
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  7. 7.0 7.1 7.2 PMID 8983520 (PMID 8983520)
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  8. PMID 21245529 (PMID 21245529)
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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

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