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Antibiotic resistance of Klebsiella pneumoniae (K. pneumoniae) has become alarming to public health, moreover biofilm production is one of the virulence mechanisms that contributes to antibiotic resistance. Metal oxide nanoparticles are showing promise as antibacterial agents. The purpose of this study was to assess the antibacterial activities and dosage effect of ZnO-NPs against ESBL K. pneumoniae isolates recovered from horses exhibiting respiratory symptoms. The antibiotic sensitivity of ESBL producing K. pneumoniae strains was tested using the Kirby Bauer disc diffusion method, which showed 100% resistance to cefotaxime and erythromycin while resistance to tetracycline, ampicillin, amoxicillin / clavulanic acid, ceftriaxone, ceftazidime, amikacin and ciprofloxacin were 85.7, 71.42, 42.85, 28.57, 28.57, 14.28 and14.28%, respectively. Regarding the biofilm production genes scanning, K. pneumoniae isolates were positive for luxS gene (100%), while only 85.7% of K. pneumoniae were positive for Uge gene and none of them having mrkD gene. ZnO-NPs were tested against a local isolate of ESBL-producing K. pneumoniae for their antibacterial properties. K. pneumoniae had MIC and MBC values of 5ug/ml and 3ug/ml, respectively. In the current study, antibiotic abuse leads to an increase in the population of ESBL-producing K. pneumoniae, posing a concern to public health. ZnO-NPs, a new material, exhibit significant antibacterial activity against hypermucoviscosity K. pneumoniae isolate. [ABSTRACT FROM AUTHOR]

Background: Potatoes are a crucial vegetable crop in Egypt in terms of production and consumption. However, the potato industry suffers significant annual losses due to brown rot disease. This study aimed to suppress Ralstonia solanacearum (R. solanacearum), the causative agent of brown rot disease in potatoes, using efficient and economical medications such as CuO and MgO metal oxide nanoparticles, both in vitro and in vivo, to reduce the risk of pesticide residues. Results: CuO and MgO metal oxide nanoparticles were synthesized via a simple chemical process. The average particle size, morphology, and structure of the nanoparticles were characterized using UV-visible spectroscopy, transmission electron microscopy (TEM), zeta potential analysis, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The growth of R. solanacearum was strongly inhibited by CuO and MgO NPs at a concentration of 3 mg/mL, resulting in zones of inhibition (ZOI) of 19.3 mm and 17 mm, respectively. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CuO-NPs and MgO-NPs were 0.5, 0.6, and 0.6, 0.75 mg/mL, respectively. When applied in vivo through seed dressing and tuber soaking at their respective MIC concentrations, CuO-NPs and MgO-NPs significantly reduced the incidence of brown rot disease to 71.2% and 69.4%, respectively, compared to 43.0% and 39.5% in bulk CuSO4 and bulk MgSO4 treatments, respectively. Furthermore, CuO-NPs and MgO-NPs significantly increased the yield, total chlorophyll content, and enzyme efficiency of potato plants compared with the infected control plants. TEM revealed that the bacterial cytomembrane was severely damaged by nanomechanical forces after interaction with CuO-NPs and MgO-NPs, as evidenced by lipid peroxidation and ultrastructural investigations. Conclusion: The results of this study suggest that CuO-NPs and MgO-NPs can be used as intelligent agents to manage plant pathogens in agriculture. The use of metal oxide nanoparticles could provide a risk-free alternative for treating plant diseases, which are currently one of the biggest challenges faced by the potato industry in Egypt. The significant increase in yield, photosynthetic pigments, enzymatic activity, and total phenol-promoted resistance to R. solanacearum in potato plants treated with CuO-NPs and MgO-NPs compared to infected control plants highlights the potential benefits for the potato industry in Egypt. Further investigations are needed to explore using metal oxide nanoparticles for treating other plant diseases. [ABSTRACT FROM AUTHOR]