To study the most important VFs of uropathogenic E coll and to test their determinants location and association with -genomic G+C content and antibiotic resistance. In this study, 321 of hospitalized and non hospitalized patients who were complaining of urinary tract infection (UTIs) symptoms were submitted to this study, urine samples :or each of them were collecr.-;;.. uropathogens identification shows that, E.coli was the most predom;au;:r (4§.(\^Enicrobacter spp. Pseudomonas spp. Klebsiella spp , Proteus spp. ('iirobc/cicr spp and Serrcnia spp were 12.1 % , 9,7 %, 5.6 % .. 4 % . 2.4% and .6% respectively. Others like Staphylococcns spp-Enterococcus spp and ('andida albicans show 10.5 %. 2.4% and 31%. Multidrug resistance was obseived among all E coll isolates. Uropathogenic E.coli isolates were screened for virulence factors (VFs) \\hidi were mannose resistant hemagglutinin antigens (11.7- 13.3%). P. rimonae (6. 7%), X adhesin (0%), aerobactrn (93.3 %) and hemolysin (35°o) as well as mannose sensitive hemagglutinin (53.3 %). The expression of some of them like hemolysin and mannose resistant hemagglutinin (MRHA) were associated with the isolates of the patients who were acquire UTIs without predisposing factors PFs (P<0.01 , P <0.05 respectively) with the absence of MSHA (P<0.05).Aerobactin is the only one which was reported as either plasmid or chromosomal-borne. Aerobactin producer E coli isolates were submitted to two methods of plasmid curing (sodium dodecyl sulfate curing and elevated temperature curing), to determine the location of aerobactin determinant. Plasmid DNA electrophoresis of the cured and uncured E coli isolates show that aerobactin plasmids are relatively large (PO.05) and cany gentamicin and chloramphem'col resistance determinants( - P <0.01 ,P<0.05) The isolates of compromised patients tend to carry aerobactin determinant on plasmids(P<0.02) and do not carry chromosomal VFs (P<0.01). On the other hand the isolates of non compromised patients earn' some or all of the chromosomal VFs including aerobactin (PO.01). The presence of pathogenicity islands (PAIs), the chromosomal determinants of VFs which have a G-C content lower than E. coll genomic G-C content.,did not correlate with the lowest limit of the genomic G-C content of E.coli. In conclusion, we found that true uropathogenic E.-coli were more likely to express VFs which are chromosomal-borne, and more likely to affect the non compromised patients. On the contrary, there is another group of E.coli isolates, do not possess these VFs, but showed plasmid aerobactin .expression . This group affect the medically or urologically compromised patients. Aerobactin plasmid are relatively large and carry the determinants of chloramphenicol or gentamicin resistance. The presence of PAIs with low G+C content in the genomes of E.coli do not associate with the lowering of genomic G-C content of E.coli isolates.