Citrobacter

Citrobacter is a genus of Gram-negative, aerobic, rod-shaped^[2] coliform bacteria of the Enterobacteriaceae family.

Citrobacter
Citrobacter freundii
Scientific classification
Domain:	Bacteria
Kingdom:	Pseudomonadati
Phylum:	Pseudomonadota
Class:	Gammaproteobacteria
Order:	Enterobacterales
Family:	Enterobacteriaceae
Genus:	Citrobacter Werkman and Gillen, 1932
Species
C. amalonaticus C. braakii C. europaeus[1] C. farmeri C. freundii C. gillenii C. koseri C. murliniae C. pasteurii[1] C. portucalensis[1] C. rodentium C. sedlakii C. werkmanii C. youngae

Citrobacter spp. cause opportunistic infections (including urinary tract infections, gastroenteritis, and bacteremia).^[2]

Microbiology

Microbial biochemistry

The species C. amalonaticus, C. koseri, and C. freundii can use citrate as a sole carbon source. Citrobacter species are differentiated by their ability to convert tryptophan to indole (C. koseri is the only citrobacter to be commonly indole-positive), ferment lactose (C. koseri is a lactose fermentor), and use malonate.^[3]

Citrobacter shows the ability to accumulate uranium by building phosphate complexes.^[4]

Environmental microbiology

These bacteria can be found almost everywhere in soil, water, wastewater, etc. They can also be found in the human intestine.^[5][6]

Clinical significance

Citrobacter are considered opportunistic nosocomial pathogens, typically associated with urinary tract infections and infant meningitis and sepsis.^[7]

Antimicrobial resistance

Citrobacter freundii strains have inducible ampC genes encoding resistance to ampicillin and first-generation cephalosporins.^[8] In addition, isolates of Citrobacter may be resistant to many other antibiotics as a result of plasmid-encoded resistance genes.^[7]