One hundred twelve urine samples were collected from Baghdad hospitals and examined by different identification techniques. Seventy isolates (62.5%) were diagnosed as Escherichia coli after microscopic and cultural identifications. The result of PCR product electrophoresis on the isolates showed that thirteen isolates (18.57%) have Pap E gene which are uropathogenic E. coli. Antibiotic susceptibility test was done, and four high resistant strains were mixed with aqueous extract of Quercus infectoria plant in 96 well ELISA plate and incubated for different times. After 0, 6, and 12 hr. of incubation, the effect of the plant extract on the bacterial growth was determined by ELISA reader, and the effect on the expression of Pap E gene was examined by real-time PCR. The results were showed that the higher effect of the extract was on the E10strain growth that dropped from 3.184 at zero time of incubation to 2.378 and 2.281 after 6, and 12 hrs. of incubation respectively. Also, shown a downregulation in the expression of Pap E gene of the isolates at different times of incubation. TheE10 strain shows decrease in the fold from 1 before the treatment with the extract to 0.076 at zero time of incubation with the extract, after 6 and 12 hrs. of incubation it shows a total down-regulation of the gene.