Citrobacter

Metal Dependencies#

Iron#

Like other Enterobacteriaceae, Citrobacter produces enterobactin and other siderophores for iron acquisition. Iron availability in the inflamed gut favors Citrobacter expansion alongside E. coli and Klebsiella, contributing to the characteristic Enterobacteriaceae bloom in Dysbiosis.^{[1]Khorsand 2022 — Overrepresentation of Enterobacteriaceae and Escherichia coli is the major gut microbiome signature in Crohn's and UC: comprehensive metagenomic analysis of IBDMDB datasetsBabak Khorsand, Hamid Asadzadeh Aghdaei, Ehsan Nazemalhosseini-Mojarad et al. · 2022Open reference 1 ↓}

Nickel#

C. freundii harbors NiFe Hydrogenase for anaerobic hydrogen oxidation, linking it to the nickel-dependent pathogen network in this wiki.^{[2]Nickel as a Catalytic Driver of Necrotizing Enterocolitis: Dietary Nickel, Microbial Metallomics, and the Activation of Nickel-Dependent Virulence Pathways in the Preterm GutKaren Pendergrass · 2026Open reference 2 ↓}

Arsenic Biotransformation#

Citrobacter species possess arsenic reductase and methyltransferase enzymes that convert inorganic arsenic to organic forms. This biotransformation capacity means Citrobacter abundance directly affects arsenic speciation and toxicity in the gut.^{[3]Arsenic and the gastrointestinal tract microbiomeMcDermott TR, Stolz JF, Oremland RS · 2020Open reference 3 ↓}

Conditions Associated#

Necrotizing Enterocolitis (NEC)#

Citrobacter is enriched in the preterm infant gut prior to NEC onset, as part of the Enterobacteriaceae bloom that precedes intestinal necrosis.^{[2]Nickel as a Catalytic Driver of Necrotizing Enterocolitis: Dietary Nickel, Microbial Metallomics, and the Activation of Nickel-Dependent Virulence Pathways in the Preterm GutKaren Pendergrass · 2026Open reference 2 ↓[4]Lin 2025 — Integrated serum metabolomics and fecal microbiome in NEC infantsZhi-ying Lin, Shan-shan He, Zi-tong Mo et al. · 2025Open reference 4 ↓} Iron and nickel availability in preterm formula may fuel this expansion.

Colorectal Cancer#

Enriched in CRC microbiome alongside other Enterobacteriaceae.^{[5]Towards the Human Colorectal Cancer MicrobiomeMarchesi JR, Dutilh BE, Hall N et al. · 2011Open reference 5 ↓[6]Identification of colorectal cancer progression-associated intestinal microbiome and predictive signature constructionJungang Liu, Xiaoliang Huang, Chuanbin Chen et al. · 2023Open reference 6 ↓} C. rodentium is the standard mouse model for studying colonic epithelial attachment and effacement—the mechanism by which EHEC causes colitis and promotes tumorigenesis.

Chronic Kidney Disease#

Citrobacter enrichment correlates with CKD severity and uremic toxin accumulation.^{[7]Wang 2023 — Perturbed Gut Microbiome and Metabolomes Across CKD SeverityWang, Li, Zhang et al. · 2023Open reference 7 ↓[8]Gut Microbiota Composition and Frailty in Elderly Patients with Chronic Kidney DiseaseElisabetta Margiotta, Francesco Miragoli, Maria Luisa Callegari et al. · 2020Open reference 8 ↓}

Cross-References#

• Enterobacteriaceae—family-level bloom in dysbiosis
• Iron—siderophore-dependent; iron availability drives expansion
• Nickel—NiFe-hydrogenase for anaerobic hydrogen oxidation
• Arsenic—biotransformation capacity affects gut arsenic speciation
• Siderophores—enterobactin production
• Necrotizing Enterocolitis—preterm gut enrichment
• Colorectal Cancer—enriched in CRC microbiome
• Chronic Kidney Disease—correlates with disease severity