Overcoming challenges in drug targeting and modulating the immunosuppressive microenvironment are critical for treating chronic bacterial infections, which are often characterized by intracellular bacteria and biofilms. To overcome these barriers, we report a multifunctional nanomedicine (CpE@BMV). The prodrug conjugate (CpE), composed of two phenylboronic acid-modified ciprofloxacin (Cip-pba) molecules and ellagic acid (Ea), self-assembles due to its hydrophobic nature and π–π stacking. Bacterial membrane vesicles (BMVs) derived from Escherichia coli aid in CpE assembly and structural stabilization. Upon administration, pathogen-associated molecular patterns on CpE@BMV engage toll-like receptors on macrophages, activating these cells and enhancing their phagocytic response. Once internalized, CpE responds to elevated intracellular H₂O₂ levels, releasing Cip to eliminate intracellular bacteria. Additionally, Ea scavenges excess reactive oxygen species in inflamed macrophages and modulates the expression of inflammatory factors, preventing an exaggerated inflammatory response. The CpE@BMV formulation also penetrates biofilms, eliminating bacteria and releasing antigens. These antigens are transported to draining lymph nodes, where they induce dendritic cell maturation and trigger a robust T and B cell-mediated immune response, helping restore immune balance and combat pathogens effectively in female mouse models. Therefore, our CpE@BMV provide an efficient strategy combining chemical and immunological therapies for chronic bacterial infection management.

Novel therapeutic strategies against difficult-to-treat bacterial infections are desperately needed, and the faster and cheaper way to get them might be by repurposing existing antibiotics. Nanodelivery systems enhance the efficacy of antibiotics by guiding them to their targets, increasing the local concentration at the site of infection. While recently described nanodelivery systems are promising, they are generally not easy to adapt to different targets, and lack biocompatibility or specificity. Here, nanodelivery systems are created that source their targeting proteins from bacteriophages. Bacteriophage receptor-binding proteins and cell-wall binding domains are conjugated to nanoparticles, for the targeted delivery of rifampicin, imipenem, and ampicillin against bacterial pathogens. They show excellent specificity against their targets, and accumulate at the site of infection to deliver their antibiotic payload. Moreover, the nanodelivery systems suppress pathogen infections more effectively than 16 to 32-fold higher doses of free antibiotics. This study demonstrates that bacteriophage sourced targeting proteins are promising candidates to guide nanodelivery systems. Their specificity, availability, and biocompatibility make them great options to guide the antibiotic nanodelivery systems that are desperately needed to combat difficult-to-treat infections.

This review highlights the significant potential of nanomedicines, including improved drug delivery, enhanced diagnostics, and immunomodulation for bacterial sepsis.

Gold nanoparticles modified with ellagic acid are prepared via a simple one-pot hydrothermal process, showing high, broad-spectrum antimicrobial activities, and effective biofilm dispersion against antibiotic-resistant ESKAPE pathogens.