In the last few years, many efforts have been devoted to investigating the antibacterial activity of metal nanoparticles, especially against multidrug-resistant bacteria. Recently extensively drug-resistant (XDR) bacteria have emerged and caused a global threat. The purpose of this manuscript was to synthesize nanostructured γ-Al₂O₃ as an antibacterial agent against some XDRs. The results showed that Al₂O₃ was a mix of rod and spherical shapes in the nano range with diameters of less than 30 nm. The zeta potential was determined to estimate the surface charge for the synthesized γ-Al₂O₃, which was recorded as −34 ± 1.8 mV, indicating good stability. The synthesized nanostructured γ-Al₂O₃ showed a potent antibacterial activity against extensively drug-resistant Acinetobacter baumanii, with an inhibition zone diameter that reached 19 mm and a minimum inhibitory concentration (MIC) value that reached 2 µg/mL. The observed antibacterial activity of the prepared Al₂O₃ nanoparticles confirmed that the main mechanistic actions include bacterial cells apoptosis, ROS increment, cellular membrane disruption, and DNA damage. The cytotoxic effect (CC50) of the prepared γ-Al₂O₃-NPs was 1250 µg/mL in a normal human lung fibroblast cell line (WI-38 cells). It can be concluded that the synthesized γ-Al₂O₃ had an acceptable toxicity, which may pave the way for its use as a potent agent in the fight against XDR bacteria.

Myositis tropicans or pyomyositis is a muscle inflammation resulting from a bacterial infection of skeletal muscle (commonly caused by Staphylococcus aureus) that usually leads to hematogenous muscle seeding. The present study was designed to estimate the role of ZnO-NPs and a physiotherapeutic program in the management of induced biceps femoris atrophy in rats through histological, biochemical, and radiological examinations at different time intervals. At the beginning, several bacterial strains were evaluated through a proteolytic enzyme activity assay and the highest activity was recorded with the Staphylococcus aureus strain. ZnO-NPs were synthesized with the arc discharge method with an average size of 19.4 nm. The antibacterial activity of ZnO-NPs was investigated and it was revealed that the prepared ZnO-NPs showed a minimum inhibitory concentration of 8 µg/mL against the tested bacterium. The cytotoxicity of the prepared ZnO-NPs was tested in C2C12 myoblast cells, and it was elaborated that CC50 was 344.16 µg/mL. Biceps femoris pyomyositis was induced with a potent strain (Staphylococcus aureus); then, a physiotherapeutic program combined with the prepared ZnO-NPs treatment protocol was applied and evaluated. The combined program claimed antibacterial properties, preventing muscle atrophy, and resulted in the most comparable value of muscle mass.