The purpose of the present study was to determine how well plantaricin and ciprofloxacin worked to prevent urinary tract infections in female rats caused by E. coli O157H7, which consisted of two steps; the first included isolation and identification of E.coli O157 H7 by using biochemical tests and VITEK II system while the second step was studying the therapeutic activity of plantaricin (which isolate from Lactobacillus plantarum and identified genetically by PCR) and ciprofloxacin against the UTIs that induced experimentally by E.coli O157:H7 in 40 female rats (which were divided into five equal groups), and comparison of these effects with ciprofloxacin. The results of this research showed that combination of planaricin and ciprofloxacin has a clear therapeutic effect in the treatment of UTIs through its effect on body weight and improved clinical markers as well as urine bacterial count and level of creatinine in serum of female rats that have been infected with E. coli O 157;H7 in compartion to animals that have been infected with E.coli O157:H7 and not been treated or with animals that treated with plantaricin or ciprofloxacin alone .This antibacterial activity that characterizes the combined of plantaricin may be due to safe antimicrobial effects against E.coli O157:H7