الفهرس 
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Abstract
The present study is conducted to compare between pathogenic and environmental E. coli through typing using both Clermont schemes. In addition, comparing their phylogenetic assignment by pathogenicity, serogroup, virulence and resistance traits. Also, the pathogenic potential of environmental isolates was compared to clinical ones via detection of panoply of virulence, toxin, DEC PAI and ExPEC PAIs genes. Also, screening for β-lactam resistance and phenotypic detection of some β-lactamase enzymes was assessed. Furthermore, this research involves molecular studies to characterize ESBLs and carbapenemase encoding genes using PCR along with their correlation with phylogenetic typing in all E. coli isolates. To our knowledge, this is the first study conducted in Egypt to investigate phylogenecity and pathogenicity of E. coli isolates from different environmental sources, based on their resistance and virulence genes repertoire. A total of 105 isolates were identified biochemically as E. coli of which, 72 isolates from clinical versus 33 isolates from environmental sources. Serological recognition clarified that, EPEC was the most widespread pathotype in clinical versus EHEC in environmental isolates. The majority of isolates were in phylogroup D (50.5%) by triplex PCR. In quadruplex PCR, clinical isolates were more prevalent in groups B2 (22.2%) and D (23.6%); whereas, environmental isolates were in groups A (24.2%) and B1 (60.6%). In addition, 17.1% of isolates were assigned as new phylogroups, C, E and F. Majority of virulence genes were higher in clinical isolates and alarming higher rate of stx2 and hlyA toxin genes was observed among environmental ones. Both DEC and ExPEC PAI markers were widespread among both categories, showing high ExPEC PAIs combination in environmental isolates. Sensitivity pattern showed higher rate of resistance to cefotaxime and cefepime in clinical and environmental isolates, respectively. Also, 50.5% of isolates were considered ESBLs producers; while, only 17.1% of isolates were carbapenemase producers. PCR revealed that, high prevalence of resistant genes and co-harbouring of ESBLs and carbapenemase encoding genes among clinical and environmental isolates, especially among those that belong to D and C phylogroups. Therefore, environmental E. coli isolates can serve as reservoirs for transmission of E. coli pathogenicity.