Ralstonia

Metal Resistance—The CzcCBA Paradigm#

R. metallidurans is the reference organism for bacterial heavy metal resistance, harboring the CzcCBA efflux system—the best-characterized multi-metal efflux pump in biology. CzcCBA exports cobalt, cadmium, zinc, and nickel, conferring survival in heavily contaminated environments.^{[1]Understanding the Development of Environmental Resistance Among Microbes: A ReviewSrivastava J, Chandra H, Singh N et al. · 2016Open reference 1 ↓}

This efflux system is the prototype for co-selection: the same CzcCBA operon that confers metal tolerance also provides resistance to multiple antibiotics, demonstrating how environmental metal pollution drives antibiotic resistance.^{[1]Understanding the Development of Environmental Resistance Among Microbes: A ReviewSrivastava J, Chandra H, Singh N et al. · 2016Open reference 1 ↓}

Cadmium-Responsive Enrichment#

Ralstonia abundance increases in response to cadmium exposure in animal models. Enriched in the gut microbiota of cadmium-exposed rats, consistent with its metal tolerance providing a selective advantage when competing organisms are inhibited by cadmium.^{[2]Liu 2023 — Environmental cadmium exposure alters the internal microbiota and metabolome of Sprague–Dawley ratsLiu S, Deng X, Li Z et al. · 2023Open reference 2 ↓[3]Environmental cadmium exposure alters the internal microbiota and metabolome of Sprague-Dawley ratsSongqing Liu, Xin Deng, Zheng Li et al. · 2023Open reference 3 ↓}

The enrichment pattern suggests Ralstonia as a potential biomarker of environmental metal exposure in gut microbiome profiling.

Disease Associations#

CKD: Enriched in gut microbiota of CKD patients, where uremic toxin accumulation creates a metal-dysregulated environment.^{[4]Liu 2023 — Changes in Gut Microbial Community upon Chronic Kidney DiseaseWu Liu, Jiaqi Huang, Tong Liu et al. · 2023Open reference 4 ↓} ASD: Altered in gut microbiota of constipated ASD children.^{[5]He 2023 — Altered Gut Microbiota and Short-Chain Fatty Acids in Chinese Children with Constipated Autism Spectrum DisorderJianquan He, Xiuhua Gong, Bing Hu et al. · 2023Open reference 5 ↓}

Infant metal exposure: Ralstonia abundance correlates with infant serum metal levels, suggesting early-life metal exposure shapes Ralstonia colonization.^{[6]Yan 2025 — Association Between Infants' Serum Levels of 26 Metals and Gut Microbiota: A Hospital-Based Cross-Sectional Study in ChinaXing Yan, Jun Qiu, Ruiwen Huang et al. · 2025Open reference 6 ↓}

PCOS: Present in vaginal microbiome of PCOS patients.^{[7]Zheng 2024 — Differential enrichment of bacteria and phages in vaginal microbiomes in PCOS and obesity: shotgun sequencing analysisZheng S, Chen H, Yang H et al. · 2024Open reference 7 ↓} Diabetes/MI: Part of gut microbiome shifts in diabetes with myocardial infarction.^{[8]A metagenomic study of the gut microbiome in patients with type 2 diabetes mellitus and myocardial infarctionHonghong Zhang, Changlin Zhai, Huilin Hu et al. · 2026Open reference 8 ↓}