ANTIBACTERIAL ACTIVITY OF SILVER NANOPARTICLES AGAINST KLEBSIELLA PNEUMONIAE THAT ISOLATED FROM BURN PATIENTS

Background: Klebsiella pneumoniae is an opportunistic pathogen notorious for causing life-threatening infections in immunocompromised patients, primarily due to its antiphagocytic polysaccharide capsule. Hypervirulent strains exhibiting a hypermucoviscous phenotype further complicate this scenario by triggering invasive infections even in healthy individuals. In burn-wound settings, this pathogen remains a leading cause of colonization and sepsis. Given the rising challenges of antimicrobial resistance, silver nanoparticles (AgNPs) have gained attention as alternative therapeutic agents with dual antibacterial and antibiofilm properties. However, data regarding the prevalence of hypervirulent K. pneumoniae in burn wounds and the efficacy of AgNPs against such clinical isolates remain limited.
Methods: A total of 100 clinical burn-wound samples were collected from November 2025 to February 2026. K. pneumoniae was isolated and identified using conventional culture, biochemical tests, and the VITEK 2 Compact system, while hypermucoviscous strains were screened via the string test. The synthesized AgNPs were characterized using UV-Vis spectroscopy, SEM, XRD, FT-IR, and AFM. Their antibacterial activity was evaluated at concentrations of 1, 0.5, 0.25, and 0.12 mg/mL, and their anti-biofilm activity was assessed using the microtiter-plate method.
Results: K. pneumoniae was recovered from 35 out of 100 burn-wound samples (35%), with 80% (28/35) of isolates testing positive for the hypermucoviscous phenotype via the string test. The synthesized AgNPs exhibited a surface plasmon resonance peak at 406 nm, spherical morphology with an average size of 35 nm, face-centered cubic crystalline reflections, and particle heights of 41.67–44.91 nm. Antibacterial activity was concentration-dependent, with mean inhibition zones of 30.3, 25.8, 20.7, and 16.0 mm at 1, 0.50, 0.25, and 0.12 mg/mL, respectively, while anti-biofilm activity was observed across all concentrations and was maximal at higher doses. 
Conclusion: The present findings reveal a considerable frequency of the hypermucoviscous phenotype among K. pneumoniae clinical isolates derived from burn wounds. Concurrently, the synthesized AgNPs demonstrated notable antibacterial and antibiofilm potential in a concentration-dependent manner. Despite these promising in vitro outcomes, the therapeutic deployment of these nanoparticles requires comprehensive preclinical and clinical evaluation, with particular emphasis on safety profiling, mechanistic pathways, and in vivo efficacy.