Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 10 6 2019 02 10 424 432 EN Seyededeh Sedigheh Hosseini Laboratory Sciences Research Center, Golestan University of Medical Sciences, Gorgan, Iran AND Department of Laboratory Sciences, Faculty of Paramedicine, Golestan University of Medical Sciences, Gorgan, Iran Ezzatollah Ghaemi Department of Microbiology, Faculty of Medicine, Golestan University of Medical Sciences, Gorgan, Iran Faramarz Koohsar Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 2018 07 29 2019 02 10 Background and Objectives: The aim of this study was to determine the effect of zinc oxide nanoparticle (ZnO-np) solution in the surface catheter on C. albicans adhesion and biofilm formation. Materials and Methods: Out of 260 isolates from urinary catheter, 133 were determined as C. albicans by common phenotypic and genotyping methods. ZnO nanoparticles with 30 nm were made by the sol-gel method, which was confirmed by XRD (X-ray diffraction) and scanning electron microscope (SEM) methods. Candidal adhesion and biofilm assays were performed on catheter surfaces for 2 and 48 hours, respectively. The effect of sub-MIC (minimum inhibitory concentrations) and MIC concentrations of ZnO-np on biofilm formation was evaluated after 24 hours using Crystal violet (CV), colony-forming unit (CFU), and SEM. Results: Out of 133 C. albicans isolates, 20 (15%) fluconazole-resistant and 113 (85%) susceptible isolates were determined by the disk diffusion method. Results showed that both isolates adhered to biofilm formation on the catheter surfaces. A significantly (P< 0.05) higher number of CFUs was evident in fluconazole-resistant biofilms compared to those formed by susceptible isolates. ZnO-np reduced biofilm biomass and CFUs of dual isolate biofilms (P< 0.05). ZnO nanoparticles had a significantly (P< 0.05) greater effect on reducing fluconazole-resistant C. albicans biofilm biomass compared to susceptible isolates. Conclusion: Zno-np exhibits inhibitory effects on biofilms of both isolates. These findings provide an important advantage of ZnO that may be useful in the treatment of catheter-related urinary tract infection. https://ijm.tums.ac.ir/index.php/ijm/article/view/1846 https://ijm.tums.ac.ir/index.php/ijm/article/download/1846/1102