Magnetic microfiber hyperthermia for synergistic antimicrobial activity against methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant global healthcare challenge, causing a range of life-threatening infections, including osteomyelitis, septic arthritis, skin and soft tissue infections, and wound infections. These infections are difficult to treat, often requiring aggressive therapeutic strategies at high antibiotic doses that increase the risk of adverse effects and drive the development of antimicrobial resistance. An alternative strategy to enhance antibiotic efficacy involves the use of locally elevated temperatures to increase the bacterial susceptibility to drugs. This can be achieved non-invasively, using magnetic hyperthermia induced by superparamagnetic iron oxide nanoparticles (SPIONs) in an alternating magnetic field (AMF). This study, presents a synergistic platform combining magnetic hyperthermia and antibiotic therapy to combat MRSA infections. Magnetic microfibers were fabricated by electrospinning using poly(methyl methacrylate) and tributyl citrate, incorporating functional Mn0.25Fe2.75O4 nanoparticles. The microfibers were systematically optimized to attain necessary tensile strength and heating efficiency for localized treatment of MRSA. Upon AMF exposure, the SPION-loaded microfiber discs achieved tunable temperatures exceeding 60 °C, controlled by varying the microfiber disc weight. The combination of doxycycline and magnetic hyperthermia exposure for 15 min demonstrated significant synergistic effects against MRSA at temperatures above 50 °C. In vitro, the antibiotic efficacy of doxycycline was enhanced by up to 35 % against MRSA, even at sub-inhibitory drug doses. The use of biocompatible materials in magnetic microfibers makes them well suited for localized therapy, particularly for treating wound infections. Additionally, the synergistic combination of magnetic hyperthermia with antibiotic therapy could enable lower drug doses, reducing the antibiotic burden and helping to combat antimicrobial resistance.