UTI is the most common infection in all ages and urinary catheters especially long-term catheterization are important predisposing factors of UTI. Urinary catheters are used in different hospital wards as a complementary curative method for the patients who are undergone various surgical procedures, such as : cesarean, hysterectomy , laparotomy, etc and they who are unable to control their voided urine .

226 urine specimens were collected from 119 catheterized patients which had been hospitalized in seven wards of Razi and Golestan hospitals in Ahwas city . At least two urine specimens were collected from each patient , before and after the insertion of the catheter . All of the specimens were inoculated to suitable Media, after transportation to the Microbiology Lab . Isolated colonies were identified and their resistance patterns were
   determined by the standard disk diffusion method (Kirby –Bauer procedure ) to 8 different antibiotics.

38 cases (43.6%) out of 87 patients showed Bacteriuria in the end of catheterization . They had no bacteriuria symptoms or sign before the catheterization. The most cases(28.9%) of bacteriuria occured in 30-39 years group and the lowest cases (2.6 %) of them occured in 60-69 years group.    Out of 50 bacterial strains isolated from urine cultures , E.coil (with 17 cases )
   was the highest (34%) and Staphylococcus aureus , Klebsiella pneumoniae , Edwardsiella tarda , Enterobacter sakazakii (with 2% for each) were the lowest cases. E.coli, Enterobacter and Kl. rhinoscleromatis , showed the most resistance to Ampicillin, Penicillin , Cephalexin , and the lowest rate to Nalidixic acid, Gentamicin and Nitrofurantoin . Staphylococcus epidermidis
   isolates ,also,showed the most resistance (100%) to Penicillin and Ampicillin , and the lowest rate to Gentamicin (with 66.7%), Cotrimoxazol and Nitrofurantoin (with 50%) .

         The results of this study suggested that catheterization , especially long- term catheterization causes the rise of urinary infections and so it is
   recommended that urinary catheters be avoided whenever possible.