Pathogenic bacteria grown in iron and zinc milieu exhibit magnetotaxis

Magnetotactic bacteria (MTB) are the only microorganisms that are known to form intracellular magnetic nanoparticles. Iron and zinc are important elements required for the survival of pathogenic bacteria. While the host immunity prevents the bacteria easy access to these elements, virulent bacteria have evolved multiple mechanisms to access these elements. The response of pathogenic bacteria like Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae was evaluated in the presence of iron and zinc. The treated bacteria revealed intracellular distribution of superparamagnetic nanoparticles comprising of zinc ferrite, and the bacteria responded to magnetic field with magnetotaxis. Similar intracellular biomineralization was observed in bacteria obtained from blood specimens of patients with sepsis. In brief, this study provides a hitherto unknown phenomenon of bacterial biomineralization. SummaryPathogenic bacteria treated with iron and zinc precursors form intracellular magnetic nanoparticles and display magnet-induced migration.