Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Botany and Microbiology

Uropathogenic Escherichia coli is one of the major pathogens causing urinary tract infections. This study aimed to identify the prevalence of antibiotic resistance among pathogenic E. coli isolated from patients with urinary tract infections and evaluation of plant- derived essential oils as alternatives to antibiotics. Of 100 strains, 78 were classified as multidrug resistant. Fifty quinolone-resistant strains were selected and subjected to phenotypic characterization. Furthermore, virulence genes and quinolone-resistance genes were investigated. The most prevalent virulence gene was found to be ear, and results revealed high frequency mutations in quinolone resistance determining region (QRDR) of DNA gyrase (gyrA) and topoisomerase IV (parC) genes. Also, aac(6{u2032})-Ib-cr gene was the most prevalent plasmid-mediated quinolone resistance determinant. The antibacterial potential of ten essential oils was investigated and results revealed that clove and oregano were the most powerful essential oils with MIC 0.25 and 1 æL/mL, respectively. The present results suggest that plant-derived EOs may assist in antimicrobial fight, especially those contain high amounts of eugenol and terpenoids (such as clove and oregano) which are active against multidrug-resistant strains

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