Search Results (426)

Background/Objectives: Targeted pulmonary delivery of antibiotics offers a favorable approach for the treatment of lower respiratory tract infections (LRTIs) by enhancing local drug concentrations while minimizing systemic exposure. This study aimed to develop and characterize fatty acid-based nanostructured lipid carrier (NLC) microparticles, including tobramycin-loaded formulations, and assess their potential application as carriers for pulmonary drug delivery. Methods: Tobramycin-loaded NLC microparticles were prepared using a hot emulsification method, with lauric acid as the solid lipid and oleic acid as the liquid lipid. The obtained formulations were characterized in terms of morphology, particle size distribution, zeta potential, thermal properties, encapsulation efficiency, drug-release behavior, aerodynamic properties, and powder flowability. Antibacterial activity was evaluated against S. aureus and P. aeruginosa, while cytocompatibility was assessed using BEAS-2B human-lung epithelial cells. Results: The developed microparticles exhibited spherical morphology, with particle characteristics influenced by lipid composition. Incorporation of oleic acid increased tobramycin encapsulation efficiency, reaching approximately 75% at liquid lipid concentrations of 5–15%. Theoretical aerodynamic diameters remained within the respirable range, and increasing oleic acid content improved powder flowability. Drug-release behavior was strongly dependent on lipid composition, with the optimized formulation providing prolonged tobramycin release over 72 h. All formulations preserved antibacterial activity against S. aureus and P. aeruginosa and demonstrated good cytocompatibility with BEAS-2B cells. Conclusions: Fatty acid-based nanostructured lipid microparticles represent a promising active carrier platform for the pulmonary delivery of tobramycin. The developed system demonstrated efficient drug encapsulation, satisfactory particle characteristics, controlled drug release, preserved antibacterial activity, and good biocompatibility, making them a suitable component of dry powders for inhalation (DPI). Full article

N-acetylcysteine (NAC) is a synthetic derivative of L-cysteine, known since the mid-20th century as a mucolytic agent and, in recent decades, has attracted attention for its antioxidant and antibiofilm properties. Bacterial biofilms are structured communities of microorganisms enclosed in an extracellular polymeric matrix, which accounts for their markedly increased resistance to antibiotics (up to 1000-fold higher than in planktonic forms) and to the host immune response. According to the literature, up to 65% of infectious agents are associated with biofilm formation, making them a challenging therapeutic target. This review systematizes current data on the molecular mechanisms of the antibiofilm action of NAC, including disruption of matrix proteins and polysaccharides, degradation of extracellular DNA, suppression of the quorum sensing system, and disturbance of bacterial redox homeostasis. Particular attention is given to synergistic combinations of NAC with antibiotics of five major classes; effective concentrations are provided, and the types of interaction are characterized. The results of clinical studies from the last decade are reviewed, demonstrating the potential of NAC as an adjuvant in urinary tract infections, chronic rhinosinusitis, diabetic osteomyelitis, and cystic fibrosis. The main limitations (pH dependence, instability, low oral bioavailability) are critically evaluated, and approaches to overcoming them using nanoparticles, hydrogels, and combinations with propolis or chitosan are proposed. The review is intended for researchers in antimicrobial chemotherapy and developers of new drug delivery systems. Full article

Background/Objectives: Ceftriaxone (Ctx) is a third-generation cephalosporin widely used to treat infections caused by Gram-positive and Gram-negative bacteria. However, its clinical efficacy may be limited by rapid systemic elimination and suboptimal tissue distribution. Erythrocyte-based targeted drug delivery systems (TDDSs) have emerged as a promising approach to prolong drug circulation and enhance site-specific accumulation. This study investigated the pharmacokinetic profile and tissue distribution of ceftriaxone encapsulated in autologous erythrocytes (RBC-Ctx) compared with free ceftriaxone (Free-Ctx) following intravenous administration in rats. Methods: Ceftriaxone was encapsulated into autologous rat erythrocytes using a hypoosmotic hemolysis loading technique. Drug-loaded erythrocytes are called pharmacocytes. Adult male Wistar rats received a single intravenous injection of Free-Ctx or RBC-Ctx at an equivalent ceftriaxone dose of 340 mg/kg. Plasma samples were collected over 24 h for pharmacokinetic analysis, while the liver, spleen, lungs, kidneys, heart, pancreas, and skeletal muscle were harvested at 1 and 12 h for tissue distribution studies. Ceftriaxone concentrations were quantified by high-performance liquid chromatography with UV detection. Results: Erythrocyte encapsulation significantly modified the pharmacokinetic behavior of ceftriaxone. Compared with Free-Ctx, RBC-Ctx prolonged the elimination half-life (4.4 ± 0.6 vs. 1.8 ± 0.1 h), increased systemic exposure (AUC₀–last, 1.6 ± 0.1 vs. 1.2 ± 0.2 mg·h/mL), reduced total body clearance (218.2 ± 11.0 vs. 294.0 ± 48.8 mL/h/kg), and increased the apparent volume of distribution at steady state (688.3 ± 61.0 vs. 435.0 ± 23.1 mL/kg). In addition, RBC-Ctx was associated with a distinct relative tissue-distribution pattern of ceftriaxone, particularly in reticuloendothelial system-rich organs such as the liver and spleen, while ceftriaxone remained detectable in several tissues at 12 h after administration. In contrast, ceftriaxone concentrations following Free-Ctx declined markedly or became undetectable over the same period. Conclusions: Encapsulation of ceftriaxone into autologous erythrocytes substantially prolonged systemic circulation, enhanced drug exposure, reduced clearance, and altered the relative tissue distribution of ceftriaxone. These findings demonstrate that erythrocyte-based carriers effectively modulate ceftriaxone pharmacokinetics and tissue distribution, supporting their potential as a targeted antibiotic delivery platform for improving antimicrobial therapy, particularly for infections involving reticuloendothelial system-associated tissues. Further studies in experimental models of infection and inflammation are warranted to evaluate therapeutic efficacy under pathological conditions and to optimize this delivery strategy. Full article

Periprosthetic joint infection (PJI) remains one of the most serious complications of arthroplasty, largely due to the formation of microbial biofilms on implant surfaces. Biofilm-associated infections exhibit increased tolerance to antimicrobial therapy and host immune responses, making eradication difficult and often requiring repeated surgical interventions. Consequently, there is a growing need for effective local therapeutic strategies capable of delivering high concentrations of antimicrobial agents directly to the site of infection while minimizing systemic toxicity. Hydrogels have emerged as promising drug delivery platforms for the management of biofilm-associated PJI. Their biocompatibility, injectability, high water content, and tunable physicochemical properties enable controlled and localized release of therapeutic agents within the infected peri-implant environment. This narrative review summarizes recent advances in hydrogel-based approaches, including antibiotic-loaded hydrogels, systems incorporating anti-biofilm enzymes, bacteriophage-loaded formulations, and nanoparticle-enhanced platforms. It also highlights future research directions, with particular emphasis on the need for expanded clinical studies to facilitate the translation of emerging hydrogel-based therapies into clinical practice. Further development of these systems should focus on the incorporation of novel therapeutic agents into hydrogel platforms, aiming to enhance biofilm eradication and improve treatment outcomes in patients with PJI. Particular attention is given to stimuli-responsive (“smart”) hydrogels that release therapeutic payloads in response to infection-related triggers such as pH changes, with emphasis on the need for expanded clinical studies to facilitate the translation of emerging hydrogel-based therapies into clinical practice. Further development of these systems should focus on the incorporation of novel therapeutic agents into hydrogel platforms, aiming to enhance biofilm eradication and improve treatment outcomes in patients with PJI. Full article

Drug delivery systems (DDSs) have attracted significant attention due to their ability to enhance therapeutic efficacy while minimizing side effects. In this study, vancomycin (VCM)-loaded calcium phosphate-liposome (CaPLip) composite nanoparticles were developed as a pH-responsive drug delivery system. The CaPLip nanoparticles were fabricated by in situ calcium phosphate precipitation on preformed liposomal templates in the presence of VCM, allowing the drug to be incorporated within the calcium phosphate matrix and adsorbed onto the CaP-coated surface (VCM-CaPLip). Structural and morphological characterization using FT-IR, XRD, and TEM confirmed the successful formation of calcium phosphate-coated liposomal nanoparticles with particle sizes ranging from 300 to 700 nm and a negative surface charge. The developed system exhibited an overall drug-loading efficiency of 47.28% and effectively reduced the initial burst release under physiological conditions. Equilibrium adsorption studies performed using preformed CaPLip nanoparticles demonstrated that VCM adsorption was well described by the Langmuir isotherm, indicating a high affinity of VCM for the CaP-coated surface under equilibrium conditions. Drug release studies at pH 4.0, 6.5, and 7.4 revealed pronounced pH-dependent behavior, with sustained release at pH 7.4 and accelerated release under acidic conditions. Changes in electrical conductivity provided supporting evidence for calcium phosphate dissolution accompanying drug release under acidic conditions. Kinetic analysis indicated a transition from predominantly diffusion-controlled release at physiological pH to diffusion-dissolution coupled release under acidic conditions. These findings demonstrate that CaPLip nanoparticles provide an effective pH-responsive antibiotic delivery platform and show potential for controlled drug release in infection-associated mildly acidic microenvironments. Full article

Chronic wounds are complex environments marked by persistent inflammation, oxidative stress, hypoxia, and conditions that favor antimicrobial resistance (AMR). Conventional antibiotics often fail due to bacterial persistence and the physicochemical barriers of the wound milieu. Biofilm-associated extracellular polymeric substances (EPS), efflux pump activity, quorum sensing (QS), and horizontal gene transfer (HGT) collectively drive antimicrobial tolerance and resistance dissemination, turning chronic wounds into reservoirs of multidrug-resistant pathogens. Consequently, emerging wound therapies demand multifunctional strategies that modulate the wound microenvironment while interfering with resistance-associated phenotypes. Hydrogel–metal–organic framework (MOF) composites have been explored as multifunctional interfaces that combine extracellular matrix-mimetic properties, tunable porosity, stimuli-responsiveness, and controlled therapeutic delivery with the bioactive functions of MOFs. Depending on their composition and architecture, these systems may exert antimicrobial and antibiofilm effects through ionic, electrostatic, osmotic, catalytic, and oxidative mechanisms, while also influencing ROS levels, inflammation, angiogenesis, and local drug transport. However, antimicrobial activity alone does not equate to resistance modulation. Evidence for direct effects on efflux systems, resistance phenotypes, or HGT remains inconsistent across reported platforms. This review critically examines representative hydrogel–MOF systems for chronic wound applications, comparing their composition, physicochemical properties, biological functions, proposed resistance-related mechanisms, advantages, limitations, and current level of evidence. We emphasize distinguishing experimentally demonstrated resistance-modulating effects from mechanistically proposed functions, and identifying design trade-offs and evidence gaps that must be addressed to develop wound interfaces capable of both supporting tissue regeneration and improving infection control. Full article

Azithromycin is widely used in dentistry as a systemic antibiotic, particularly for odontogenic infections and as an alternative in patients with β-lactam hypersensitivity. Beyond its antimicrobial activity, azithromycin possesses unique pharmacokinetic, anti-inflammatory, immunomodulatory, and anti-biofilm properties. Together with growing concerns regarding antimicrobial resistance and antibiotic stewardship, these characteristics have stimulated interest in local drug-delivery strategies that may reduce systemic antibiotic exposure while maintaining therapeutic efficacy. This narrative review evaluates the rationale, potential clinical applications, and current evidence supporting local azithromycin delivery in dentistry. The available literature on azithromycin pharmacology, systemic dental use, immunomodulatory mechanisms, biofilm-related effects, local drug-delivery systems, safety, and regulatory considerations was critically reviewed. Current evidence suggests that locally delivered azithromycin may achieve high drug concentrations at the target site, enhance anti-biofilm activity, modulate local inflammation, and minimize systemic exposure. Potential applications include periodontitis, peri-implant diseases, persistent endodontic infections, oral surgery, and regenerative procedures such as bone augmentation and maxillary sinus floor elevation. Emerging delivery platforms, such as hydrogels, thermoresponsive gels, nanoparticles, and chitosan-based systems, further support the feasibility of this approach. Experimental findings also indicate that azithromycin may inhibit osteoclast activity, suggesting additional benefits for bone preservation and regenerative healing. Despite these promising findings, current evidence remains limited and is derived mainly from preclinical studies and small clinical investigations. Further translational research and well-designed randomized controlled trials are needed to establish the safety, efficacy, and optimal clinical role of locally delivered azithromycin in evidence-based dental practice. Full article

Helicobacter pylori is one of the most common bacterial pathogens in humans and the primary etiological agent of chronic gastritis, peptic ulcer disease, and gastric cancer. Its ability to establish persistent gastric colonization relies on multiple virulence factors, including adhesins, urease, cytotoxins, motility, outer membrane vesicles, and biofilm formation, which collectively promote bacterial survival, chronic inflammation, and treatment failure. The increasing prevalence of antibiotic-resistant H. pylori strains has intensified the search for therapeutic strategies targeting both bacterial viability and virulence. Berberine (BBR), a natural isoquinoline alkaloid, has emerged as a promising candidate because of its antibacterial, anti-inflammatory, and antioxidant properties. Increasing evidence derived from native berberine, its derivatives, and berberine-based formulations indicates multifaceted anti-H. pylori activity, including direct antibacterial effects, inhibition of virulence determinants, and modulation of host inflammatory responses. This review summarizes current knowledge on the epidemiology and pathogenic mechanisms of H. pylori and provides a comprehensive overview of the available evidence regarding the anti-H. pylori pharmacological profile of BBR-based compounds. Particular attention is given to their effects on bacterial adhesion, motility, urease activity, efflux pump function, biofilm formation, and host inflammatory signaling pathways. The review also discusses findings from preclinical and clinical studies supporting BBR-based strategies as adjuncts to conventional eradication therapies. In addition, recent advances in nanotechnology-based drug delivery systems designed to overcome the poor oral bioavailability of BBR and improve its therapeutic efficacy against H. pylori are highlighted. Full article

In this study, alginate hydrogels (A) cross-linked with a mixture of calcium and europium ions (Ca+Eu)A were developed for the first time as potential carriers for the targeted delivery and sustained release of drugs to specific regions of the gastrointestinal tract. Comparative studies were conducted to investigate the effect of the cross-linking agent (Ca²⁺, Eu³⁺, or their mixture) on the physicochemical properties of alginate hydrogels and the release kinetics of metronidazole in media simulating different gastrointestinal environments. Rheological analysis demonstrated that (Ca+Eu)A hydrogels form mechanically robust, highly cross-linked networks. The hydrogels exhibited negligible swelling in an acidic medium (swelling ratio, SR ≈ 1–1.5 g/g); however, in PBS, calcium alginate (CaA) hydrogels swelled 7–8 times more (SR ≈ 42.5 g/g) than hydrogels cross-linked with Eu³⁺ ions or a Ca²⁺/Eu³⁺ mixture (SR = 5–8 g/g). Metronidazole was released 1.5–2 times faster from calcium-cross-linked hydrogels than from hydrogels cross-linked with Eu³⁺ ions or the mixed Ca²⁺/Eu³⁺ system, whereas (Ca+Eu)A hydrogels exhibited a more sustained and uniform release profile. These results demonstrate that the drug release kinetics can be tuned by adjusting the Ca²⁺/Eu³⁺ ratio during alginate cross-linking. Consequently, such hydrogels represent a promising platform for the targeted delivery and controlled release of therapeutic agents, particularly antibiotics, to specific regions of the gastrointestinal tract. Full article

Background: Despite extensive development of liposomal antibiotics, the structural determinants governing their stability, release, and biological activity remain poorly understood. This study investigated how the cholesterol content and drug-to-lipid ratio affect membrane organization and thereby determine the physicochemical and biological properties of linezolid-loaded liposomes. Methods: Nine liposomal formulations, varying in their cholesterol content (10–30 wt%) and drug-to-lipid ratios (1–5%), were prepared by thin-film hydration. Membrane organization was analyzed by ATR-FTIR spectroscopy and principal component analysis. Liposomes were further characterized by particle size, ζ-potential, encapsulation efficiency, storage stability, in vitro release in phosphate buffer with and without bovine serum albumin, antibacterial activity against B. subtilis, and antimycobacterial activity in an ex vivo PBMC-derived Mycobacterium tuberculosis granuloma model. Results: The cholesterol content and drug-to-lipid ratio markedly altered membrane interfacial organization, particularly the hydration of the carbonyl and phosphate regions. These structural changes correlated with differences in storage stability, protein-responsive release, and antibacterial activity. Functional behavior was non-monotonic, as 30-L showed the highest overall storage stability, while the apparent release depended jointly on the cholesterol content, drug loading, and medium. BSA altered the composition-dependent release pattern instead of producing a uniform effect. In the exploratory granuloma model, the formulations 10-S, 10-L, and 30-M reduced M. tuberculosis CFU by >99%, whereas free linezolid produced approximately 60% inhibition. Conclusions: Membrane interfacial organization is a key determinant of the functional performance of liposomal linezolid, establishing a structure–property–function relationship that provides a mechanistic basis for the rational design of liposomal antibiotic delivery systems for tuberculosis therapy. Full article

Nanomedicine-based liposomal delivery systems are gaining increasing attention as advanced therapeutic platforms for managing ocular infections associated with antimicrobial resistance (AMR) and biofilm formation. The primary objective of this review is to critically evaluate the potential of liposomal drug delivery systems for improving the treatment of antimicrobial-resistant and biofilm-associated ocular infections by integrating current knowledge on antimicrobial resistance mechanisms, biofilm-targeted therapeutic strategies, and advances in liposomal formulations, while also identifying the major limitations, translational challenges, and knowledge gaps in this rapidly evolving field. Traditional ocular antimicrobial treatments are frequently limited by poor drug penetration, short precorneal residence time, low bioavailability, systemic side effects, and inadequate activity against resistant microorganisms and biofilm-embedded pathogens. This review provides a comprehensive overview of different liposomal systems, including conventional, cationic, polyethylene glycol (PEG)-modified, deformable, and stimulus-responsive liposomes, and discusses their advantages in ophthalmic drug delivery, such as enhanced corneal permeation, prolonged drug retention, controlled release, improved biocompatibility, and reduced ocular toxicity. The review further examines the mechanisms through which liposomes help overcome AMR, including improved epithelial transport, membrane disruption, intracellular drug delivery, efflux pump evasion, and enhanced antimicrobial efficacy. In addition, liposomal approaches targeting ocular biofilms are explored, focusing on improved biofilm penetration and the delivery of anti-biofilm agents such as antibiotics, enzymes, quorum-sensing inhibitors, and antimicrobial peptides. Current evidence from in vitro and in vivo ocular infection models is summarized together with disease-specific applications in keratitis, endophthalmitis, and contact lens-related infections. The article also compares liposomes with other ocular nanocarriers and addresses important considerations related to safety, stability, sterilization, large-scale production, and regulatory translation. In addition to highlighting recent advances, this review critically discusses the current limitations of liposomal formulations, the major barriers to clinical translation, and the key knowledge gaps that should be addressed to facilitate the future development and successful clinical application of these systems. Finally, emerging directions including ligand-targeted and stimulus-responsive liposomes, AI-driven formulation development, personalized nanotherapy, and gene therapy combinations are discussed as promising future strategies for combating resistant ocular infections. Full article

Antimicrobial resistance (AMR) in respiratory infections represents a major global health challenge, compounded by biological barriers that limit the effectiveness of conventional antibiotics, including mucus hypersecretion, biofilm formation, and intracellular pathogen persistence. Nanotechnology has emerged as a promising platform for addressing these limitations through advanced drug-delivery strategies. This narrative review provides an integrated overview of nanocarrier systems—including lipid-based (e.g., liposomes, solid lipid nanoparticles), polymeric (e.g., PLGA, chitosan), and inorganic nanoparticles (e.g., silver, gold, zinc oxide)—with emphasis on their pharmaceutical design parameters for pulmonary delivery. Key mechanisms by which nanotechnology enhances antimicrobial efficacy include targeted and controlled drug delivery, improved penetration of mucus and biofilms via surface engineering, synergistic combination therapies, and intrinsic antimicrobial activity through mechanisms such as reactive oxygen species generation. Preclinical studies targeting major respiratory pathogens, including Pseudomonas aeruginosa, Mycobacterium tuberculosis, Streptococcus pneumoniae, and methicillin-resistant Staphylococcus aureus, demonstrate enhanced biofilm disruption, intracellular drug delivery, and reductions in bacterial burden. However, important translational challenges remain, including long-term safety, manufacturing scalability, regulatory complexity, and the potential for microbial adaptation. Future directions focus on stimuli-responsive systems, inhalable formulations, and biomimetic platforms to improve targeting and therapeutic precision. Collectively, nanotechnology represents a delivery-oriented strategy with the potential to enhance existing antimicrobial therapies and support the development of more effective interventions against resistant respiratory infections. Full article

Antimicrobial resistance (AMR) among pathogens involved in intra-abdominal infections (IAIs) represents a critical and escalating clinical challenge. The interconnected nature of antimicrobial resistance, spanning human medicine, veterinary practice, agricultural use and environmental reservoirs, has required coordinated international responses based on the ‘One Health’ principle. This study presents an update on efforts underway worldwide to develop new antibiotics, novel combined antimicrobial agents, and alternatives to classic therapies for IAIs. New antibiotics or compounds with antibacterial activity are currently in various stages of clinical trials, including several fluoroquinolones, beta-lactamase inhibitors, and polymyxin analogues. To reduce the risk of bacterial resistance, various additions to antimicrobial treatments are being explored, such as nanoparticles (NPs), antimicrobial peptides (AMPs), bacteriophages, the CRISPR/Cas system, and probiotics. Each modality offers distinct mechanisms that circumvent established resistance pathways, including multi-target membrane disruption, sequence-specific gene editing, and microbiome restoration. Current preclinical and clinical evidence is synthesized, and key translational barriers, including delivery challenges, safety concerns, regulatory complexity, and the need for IAI-specific pharmacokinetic data are critically examined. In conclusion, the convergence of novel antibiotic agents and non-traditional antimicrobial strategies reviewed herein provides the foundation for a new paradigm in the management of drug-resistant IAIs. The transition from a monotherapy-centric approach to an integrated, multi-modal treatment framework, guided by rapid diagnostics and informed by antimicrobial stewardship, will be essential to preserve therapeutic efficacy against AMR threats of the coming decades. Full article

Poor adherence to prolonged antibiotic regimens remains a major challenge in the treatment and prevention of chronic infectious diseases such as tuberculosis. Transdermal drug delivery systems capable of sustained antibiotic release may improve therapeutic compliance while reducing the need for frequent oral administration. In this study, electrospun polymeric membranes based on poly(lactic acid) (PLA) and poly(ε-caprolactone) (PCL) were developed as transdermal rifampicin delivery platforms. Homogeneous nanofibrous membranes with average fiber diameters of approximately 250 nm were successfully fabricated and exhibited efficient drug incorporation while preserving the structural integrity of the polymeric matrix. The electrospun membranes retained sufficient tensile strength and dimensional stability after accelerated temperature–humidity aging, supporting their stability during storage, handling, and application. In vitro cytotoxicity and biocompatibility assays using primary human peripheral blood mononuclear cells (PBMCs) demonstrated that the developed systems did not induce significant cytotoxic or pro-inflammatory responses. Transdermal permeation studies using an in vitro mouse skin model demonstrated sustained rifampicin diffusion for at least 72 h. Importantly, the antibiotic recovered after skin permeation preserved antimycobacterial activity against Mycobacterium tuberculosis H37Ra and Mycobacterium bovis BCG, confirming that rifampicin maintained its biological functionality after electrospinning and transdermal migration. Overall, these findings demonstrate the potential of electrospun PLA/PCL membranes as stable and biocompatible transdermal antibiotic delivery systems capable of sustained release and preservation of antimicrobial activity. This proof-of-concept study supports the translational potential of electrospun polymeric platforms for controlled antibiotic delivery in long-term infectious disease therapies. Full article

Conventional antibiotics exhibit limited ability to penetrate host cell membranes, making intracellular bacterial infections difficult to eradicate completely. As naturally derived nanoscale membrane structures, bacterial extracellular vesicles (EVs) possess excellent biocompatibility and intrinsic transmembrane transport capability, thereby demonstrating unique advantages for in vivo drug delivery. The present study investigated the feasibility of using EVs derived from the avirulent Streptococcus suis T15 as novel carriers for ciprofloxacin delivery. We also comprehensively evaluated the biosafety and anti-infective efficacy of this nanodrug delivery system in vitro and in vivo. Cytotoxicity assays, live/dead cell staining, and hemolysis analyses demonstrated that T15-derived EVs at concentrations below 50 μg/mL did not cause significant cellular damage or hemolysis. Serum biochemical analyses in mice further confirmed the absence of obvious organ toxicity, indicating favorable biosafety within the tested concentration range. Ciprofloxacin was successfully loaded into EVs using a combination of ultrasonication and electroporation, achieving a drug concentration of 438.6 μg/mL and a loading efficiency of 10.96%. The ciprofloxacin-loaded EVs (EV-CIP) exhibited significantly greater antibacterial activity than free ciprofloxacin against both intracellular bacteria and fluoroquinolone-resistant strains exhibiting efflux pump activity. Evaluation in animal infection models showed that EV-CIP markedly reduced mortality in infected Galleria mellonella larvae. It also decreased bacterial burdens in multiple mouse organs and significantly alleviated histopathological damage. These results collectively suggest that EVs derived from the avirulent S. suis T15 were safe and effective within the tested concentration range and experimental conditions. The EV-based ciprofloxacin delivery system substantially enhanced the clearance of intracellular pathogens and fluoroquinolone efflux pump-positive bacteria, suggesting its potential application in the treatment of difficult-to-treat bacterial infections. This study provides a theoretical and experimental basis for the further development of novel EV-based anti-infective drug delivery strategies for livestock and poultry. Full article