Pneumonia

Metal Ecology#

Zinc vs. manganese: Host Calprotectin (S100A8/A9) sequesters both zinc (Zn) and manganese (Mn) at infection sites. S. pneumoniae responds by upregulating high-affinity manganese transporters (PsaA) to maintain manganese-SOD defense against oxidative killing.

Zinc can directly inhibit pneumococcal manganese uptake, providing a mechanistic basis for zinc supplementation in pneumonia.^{[1]Eijkelkamp et al. 2014 — Extracellular Zinc Competitively Inhibits Manganese Uptake in Streptococcus pneumoniaeBart A. Eijkelkamp, Jacqueline R. Morey, Stephanie L. Neville et al. · 2014Open reference 1 ↓}

Iron: Pneumonia pathogens deploy siderophores and heme acquisition systems; host Hepcidin elevation during infection restricts systemic iron.^{[2]Infection metallomics for critical care in the post-COVID eraPatil RH, Luptakova D, Havlicek V · 2021Open reference 2 ↓}

Infection metallomics: Siderophore and metallophore detection in patient specimens enables pathogen identification and outcome prediction in critical care.^{[2]Infection metallomics for critical care in the post-COVID eraPatil RH, Luptakova D, Havlicek V · 2021Open reference 2 ↓}

Gut-Lung Axis#

Gut Dysbiosis increases pneumonia susceptibility via impaired systemic immune priming. COVID-19 pneumonia is compounded by gut barrier failure and Endotoxemia.^{[3]Brown et al. 2024 — Pathophysiology, Diagnosis, and Management of Neuroinflammation in COVID-19Rachel L Brown, Laura Benjamin, Michael P Lunn et al. · 2024Open reference 3 ↓} Antibiotic treatment of pneumonia disrupts gut Colonization Resistance, enabling secondary infections.