Efeito de antibiótico vetorizado com nanopartículas magnéticas para tratamento da infecção por Staphylococcus aureus multirresistente

Abstract

Staphylococcus aureus are historically recognized as important human pathogens. They are spherical and Gram positive bacteria constituting the normal microbiota of the skin and mucosa of most mammals, including humans. Organic factors such as host immunity and integrity of the skin barrier, as well as factors innate to the microorganism as virulence, contribute to the initial symbiosis condition becoming a pathogenic relationship, resulting from simple cutaneous and subcutaneous conditions to severe systemic infections. Despite its intrinsic virulence, since the use in the clinical practice of Penicillin in the 1940s, these bacteria began to develop resistance. The increase of methicillin resistant Staphylococcus aureus (MRSA) insensitive to the multiple antibiotics employed in clinical practice is a worrying phenomenon, since, in addition to reducing the therapeutic options, it has contributed to the worldwide dissemination of this agent, threatening public health as it increases mortality, morbidity and treatment costs. In this sense, new clinical strategies are necessary and urgent, and among them, the vectorization of antibiotics through magnetic field has been shown to be a promising technique. Magnetic targeting allows, in addition to the selective delivery of the drug at the site of infection, the local magnification of a very high magnetic field, altering the bacterial microenvironment. In this sense, the present study aimed to study the action of the antibiotic, Oxacillin, vectorized with magnetic nanoparticles in the treatment of skin and subcutaneous rat infections caused by multiresistant Staphylococcus aureus. The synthesized, drug bound and characterized magnetic particles were tested in vivo against models of infection with MRSA strain CCBH 4395 (Fiocruz - RJ) and the results indicated high concentration of the radiolabeled drug at the site of infection and revealed a significant reduction in the growth of CFU in samples from animals treated with the magnetic drug system, and even from those treated solely with the magnetic vector. These promising results point, perhaps, to a new paradigm of antibiotic treatment without chemical molecules, but throught the action of the magnetic field.