Iron Effects on Clostridioides difficile Toxin Production and Antimicrobial Susceptibilities

Area of Science:

• Medical Microbiology
• Oncology
• Hematology

Background:

• Red blood cell (RBC) transfusion therapy, while beneficial, can lead to iron overload.
• Iron overload causes organ damage and increases susceptibility to infections.
• Clostridioides difficile infection (CDI) is a significant nosocomial infection in cancer patients.

Purpose of the Study:

• To investigate the impact of iron overload on Clostridioides difficile growth and virulence.
• To evaluate the efficacy of iron chelators in managing iron-induced CDI.

Main Methods:

• Assessed C. difficile growth (CFU) and toxin gene expression (tcdA, tcdB) under varying iron concentrations.
• Determined minimum inhibitory concentrations (MICs) of antibiotics (metronidazole, vancomycin) in iron-exposed conditions.
• Evaluated the effect of deferoxamine (iron chelator) on iron-stimulated C. difficile growth and toxin production.

Main Results:

• Iron (Fe3+) significantly stimulated C. difficile growth and toxin A production in a dose-dependent manner.
• Excess iron increased resistance to metronidazole but not vancomycin.
• Deferoxamine treatment effectively reduced iron-induced bacterial growth and toxin levels.

Conclusions:

• Iron overload promotes C. difficile pathogenesis and alters antibiotic susceptibility.
• Iron chelators like deferoxamine show potential in mitigating CDI in iron-overloaded patients.
• Considering iron overload in CDI risk prediction models may improve patient management in oncology.