Pseudomonas aeruginosa is a widely spread microorganism with many ecological nishes including human body. Magnetite nanoparticles coated with sodium oleate and dispersed in deionized water were prepared. The magnetite suspension concentrations in the culture medium of Pseudomonas aeruginosa were equal to: 0.0075–0.015-0.03-0.06-0.12-0.25-1.0-2.0 μL/mL. Fluorescence measurements, possible due to the fluorescent properties of pyoverdine, the siderophore synthesized by this bacterium, evidenced stimulatory effect of magnetite low concentrations. Further test was based on the response of other two bacteria to the pyoverdine obtained by thermolisis of Pseudomonas cultures. The antimicrobial effect of pyoverdine against several strains of Sarcina lutea and Staphylococcus aureus (clinical isolates from hospital patients) was amplified following the treatment with magnetic nanoparticles – though no distinct correlation with the magnetic nanoparticle concentration could be emphasized.Fluorescence measurements, possible due to the fluorescent properties of pyoverdine, the siderophore synthesized by this bacterium, evidenced stimulatory effect of magnetite low concentrations. Further test was based on the response of other two bacteria to the pyoverdine obtained by thermolisis of Pseudomonas cultures. The antimicrobial effect of pyoverdine against several strains of Sarcina lutea and Staphylococcus aureus (clinical isolates from hospital patients) was amplified following the treatment with magnetic nanoparticles – though no distinct correlation with the magnetic nanoparticle concentration could be emphasized.

Pseudomonas aeruginosa este un microorganism larg răspîndit, cu multe nişe ecologice, inclusiv organismul uman. Nanoparticule de magnetită învelite cu oleat de sodium şi dispersate în apă deionizată au fost preparate în laborator. Concentraţiile de suspensie de magnetită din mediul de cultură al bacteriei Pseudomonas aeruginosa au fost de 0.0075–0.015-0.03-0.06-0.12-0.25-1.0-2.0 μL/mL. Măsuratorile de fluorescenţă, posibile datorită proprietăţilor fluorescente ale pioverdinei, sideroforul sintetizat de aceasta bacterie, au evidenţiat efectul stimulator al magnetitei în mici concentraţii. Următorul test s-a bazat pe raspunsul altor două bacterii la administrarea de pioverdină obţinută prin termoliza culturilor de Pseudomonas. Efectul antimicrobian al pioverdinei faţă de câteva surse de Sarcina lutea şi Staphylococcus aureus (izolate de la pacienţi din spital) a fost amplificat după tratarea cu nanoparticule magnetice – dar nu s-a putut evidenţia vreo corelaţie matematică cu concentraţia de nanoparticule magnetice.