الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
”In the 21stcentury, the emergence and dissemination of resistant bacteria to antimicrobial agents is considered a challenging threat to global public health as antibiotic resistance leads to higher medical costs, longer hospital stays, and increased mortality. β-lactam antibiotics are among the most commonly prescribed antibiotics due to their minimal side effects and broad antibacterial spectrum. However, various mechanisms are responsible for resistance to β-lactam compounds, such as the production of degrading enzymes, alteration of the drug target (modification of penicillin-binding proteins), decreased membrane permeability, and drug efflux pump. Hence this study was conducted to recognize several mechanisms mediating β-lactam resistance in E. coli, K. pneumoniae, and P. mirabilis clinical isolates collected from Mansoura University hospitals, Egypt. In addition to the investigation of the prevalence of porin alteration mediated resistance to β- lactam antibiotics in β- lactamase producing and non-producing strains of multidrug-resistant clinical isolates of E. coli, K. pneumoniae, and P. mirabilis. Furthermore, this research involves molecular studies to characterize ESBLs, AmpC and carbapenemase encoding resistant genes using PCR technique of all E. coli, K. pneumoniae and P. mirabilis isolates.