Clinical Efficacy of Silver Nanoparticle-Antibiotic Hydrogel in Chronic Wounds Infected with Multidrug-Resistant Bacteria

Abstract

Background: Chronic wounds infected with multidrug-resistant bacteria represent a therapeutic challenge due to biofilm formation, limited antibiotic options, and delayed healing. Silver-based dressings are commonly used but often fail to achieve complete bacterial clearance. Combining silver nanoparticles with antibiotics in a hydrogel matrix may offer synergistic antimicrobial activity while promoting a moist wound healing environment. Objective: To evaluate the clinical efficacy and local safety of a silver nanoparticle-antibiotic hydrogel compared to a standard silver dressing in chronic wounds infected with multidrug-resistant bacteria, specifically assessing bacterial clearance, wound contraction, symptom improvement, and healing quality. Methods: This parallel-group randomized controlled trial enrolled 78 adults with chronic wounds (≥4 weeks duration) microbiologically confirmed to be infected with methicillin-resistant Staphylococcus aureus or multidrug-resistant Pseudomonas aeruginosa. Participants were randomly assigned to receive either the silver nanoparticle-antibiotic hydrogel (n=39) or a standard silver-impregnated nanocrystalline dressing (n=39) once daily for four weeks, with a further four weeks of follow-up. The primary outcome was bacterial clearance at day 28. Secondary outcomes included wound contraction, time to complete closure, pain reduction, and scar quality. Analysis followed intention-to-treat principles using independent t-tests, paired t-tests, and repeated measures ANOVA. Results: Of 78 randomized participants, 73 completed the intervention and follow-up (intervention n=36, control n=37). At day 28, bacterial clearance was achieved in 91.7% of the intervention group versus 64.9% of the control group (p=0.004). Wound contraction was significantly greater in the hydrogel group (68.4% vs 47.3% area reduction, p=0.007), and time to complete closure was shorter (24.1 vs 31.8 days, p=0.001). Pain scores improved more markedly in the intervention group (mean reduction 4.9 vs 3.4, p<0.001). No significant difference in contact dermatitis was observed between groups. Conclusion: The silver nanoparticle-antibiotic hydrogel demonstrated superior bacterial clearance, faster wound healing, and better symptom control compared to standard silver dressing in chronic wounds infected with multidrug-resistant bacteria, without increased local adverse events.