Investigation of the effects of chitosan-zinc and colistin-chitosan nanoparticles on bapgenes in the biofilm formation of Acinetobacter baumannii

Abdul Jabbar, Yousif Salih; Ahmed, Mais Emad; Gazi, Umut

doi:10.21608/mb.2025.342997.1217

Investigation of the effects of chitosan-zinc and colistin-chitosan nanoparticles on bapgenes in the biofilm formation of Acinetobacter baumannii

Document Type : Original Article

Authors

¹ Department of Medical Microbiology and Clinical Microbiology, Faculty of Medicine, Near East University, Nicosia 99138, Cyprus.

² Department of Biology, College of Science, University of Baghdad, Baghdad, Iraq.

10.21608/mb.2025.342997.1217

Abstract

Acinetobacter baumannii is a major cause of skin infections, largely due to biofilm formation and antibiotic resistance. This study evaluates the antimicrobial potential of Chitosan-Zinc Oxide Nanoparticles (CS-ZnO-NPs) and a colistin-chitosan combination (Col-CS-NPs) against biofilm-associated, multidrug-resistant A. baumannii. CS-ZnO-NPs were synthesized using chitosan biomass and characterized via FTIR, UV-visible spectrometry, X-ray diffraction (XRD), and microscopy (TEM, FESEM, AFM). XRD confirmed a hexagonal structure, and AFM showed particle sizes of 34–65 nm. UV absorption at 235 nm reflected optical properties, while FESEM verified morphology. The microdilution method established the nanoparticles’ minimum inhibitory concentration (MIC), demonstrating antifungal activity and synergistic inhibition of fungal strains. PCR confirmed the bap gene in most isolates, and RT-PCR showed variation in gene expression. CS-ZnO-NP treatment significantly downregulated bap expression in strong biofilm producers. Cytotoxicity assays on A375 cells revealed IC50 values of 2.5 µg/mL for CS-ZnO-NPs and 1.5 µg/mL for Col-CS-NPs. CS-ZnO-NPs induced higher cell mortality. Combining CS-ZnO-NPs with agents like Extr-DA-NPs and MFX0.5SF inhibited biofilm formation and reduced bacterial fouling within 24–48 hours at 37°C. Real-time PCR confirmed decreased bap expression post-treatment. These results demonstrate a dose-dependent bactericidal effect of CS-ZnO-NPs, indicating strong therapeutic potential. Further research is warranted to explore their clinical applications and safety in managing multidrug-resistant infections.

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