The objectives of this study are summarized as follows:

1. Isolation and identification of Hypervirulent Klebsiella pneumoniae (HvKp) from clinical sources in some Baghdad hospitals.
2. Biosynthesis of chitosan-coated yeast-mediated nanoparticles and study of their antibacterial activity.
3. Study the potential effects of these nanoparticles on the gene expression of ESBL-encoding (blaSHV, blaTEM, and blaCTX-M), and virulence-associated genes (rmpA, iucA, and peg344) in HvKp isolates.

Dissertation also includes

1. Extraction process: Preparing the yeast extracts and studying the antibacterial activity of the extracts against HvKp isolates.
2. Preparation and characterization of yeast nanoparticles: Detailed analysis of the size, shape, structure, and composition of the yeast nanoparticles through techniques such as UV-Visible Absorption Spectroscopy (UV-Vis spectroscopy), Fourier Transform Infrared Spectroscopy analysis (FTIR) analysis, Scanning Electron Microscopy (SEM) analysis, Atomic Force Microscopy (AFM), Energy Dispersive X-ray (EDX) analysis, X-ray diffractometer (XRD).
3. Antibacterial activity: Evaluating the antibacterial efficacy of the biosynthesized chitosan-coated nanoparticles against HvKp.
4. Efficiency in reducing the gene expression: Investigating the nanoparticles’ ability to reduce the gene expression of HvKp.

The most important recommendations which the study has come up with and the average obtained:

1. Study the safety, efficacy, potential cytotoxicity, biodistribution, and immunomodulatory effects of Sc-NPs for medical applications and to develop practical pharmaceutical formulations, such as topical gels, wound dressings, or sprays containing Sc-NPs, for the treatment of infections caused by highly virulent strains of Klebsiella pneumoniae that produce broad-spectrum beta-lactamases (ESBLs)
2. 2. The combination of Sc-NPs with conventional antibiotics should be investigated as a potential synergistic approach to overcome multidrug resistance.
3. It is recommended to conduct broader screening of Sc-NPs against other clinically relevant pathogens, both Gram-negative and Gram-positive, as well as fungi and viruses, to assess their antimicrobial potential more broadly.
4. Improving the biosynthesis process of Sc-NPs, including particle size, stability, and chitosan encapsulation, is recommended to enhance their antibacterial and virulence effects.