urinary tract infections ( uti ) are the most common infectious complications in patients receiving renal transplantation for end stage kidney disease . uti could be associated with an increased morbidity and mortality risk , can worsen the graft and patient survival in renal transplant recipient . a significant proportion of kidney transplant recipients with utis may develop acute pyelonephritis , which is an independent risk factor for deterioration of graft function . some recent studies suggest routine prophylactic stenting of ureterovesical anastomosis at the time of graft implantation to reduce the incidence of early postoperative major urologic complications , as urinary leaks and stenosis [ 6 - 8 ] . others advocate the use of stent only in selective , difficult cases while routine stenting could be associated with specific complications as haematuria , migration , malposition or complications of removal . it has been shown , that urinary stenting could lead to a significant increase of infections of lower and upper urinary tract in immunocompromised patients . although , whether universal routine stenting of the ureteroneocystostomy is a real risk factor for the development of severe urinary tract infection ( uti ) after renal transplantation is still controversial . therefore , to help further clarify this issue , we compared the frequency of uti in our cohort of deceased donor kidney transplant recipient transplanted with or without ureteric stent implantation . this is a retrospective , observational study of deceased donor renal allograft recipients who were consecutively transplanted at university hospital essen , germany between january 2002 and december 2006 ( n = 310 ) . data for this study were obtained from our transplant database and review of electronic and paper - based medical records . all adult ( > 18 years ) deceased donor kidney transplantations , except combined multiorgan transplants were considered . living donor transplantations double - j ureteral catheters were placed intraoperatively per the surgeon 's discretion based on ureter , bladder and anastomotic characteristics until june 2004 and on routine basis thereafter . 157 patients were enrolled to a stent- ( st ) and 153 patients to a no - stent ( nst ) group . recipient and donor demographic and laboratory data , at the time of transplantation and afterwards were reviewed . urinary tract infection was defined as the patient having one of the following symptoms dysuria , fever , urgency , frequency , suprapubic tenderness , and positive urine culture with  10microorganism / cmor two of the above signs and pyuria ( > wbc / mm ) or < 105 microorganism / cmif patient was on antibiotics . intravenous cefazoline ( 2 g ) was given once perioperatively within 30 minutes prior to skin incision and repeated once when operation exceeded 3 hours . a dose of single strength trimetoprim / sulfametoxazole ( tmp / smx ) was started on day 2 or 3 and continued every second day for four to six months . all stents were removed by cystoscopy under aseptic conditions 4 - 6 weeks after transplantation . immunosuppression consisted of methylprednisolone ( 500 mg given intraoperatively , followed by sequential tapering to daily oral prednisone 30 mg by one week , 10 mg at one month and 5 mg at 6 - 12 months ) , mycophenolate - mofetil ( 2 g / d postoperatively with dose adjustment for side effects ) , calcineurininhibitors ( tacrolimus or cyclosporin - a started within 24 hours after surgery ) and/or il-2 receptor blockers ( basiliximab , daclizumab ) . estimated glomerular filtration rate ( egfr ) was calculated using the mdrd formula : egfr ( ml / min/1.73 m2 ) = 186  crs-1.154  age-0.203  0.742 ( if female ) . " extra risk " recipients were defined as recipients older than 60 years or older than 50 years with at least one of the following risk factors : coronary heart disease , peripheral arterial disease ( pad , grade iia or higher ) , diabetes mellitus . patients with findings suggestive of uti were hospitalized for further work - up and treatment , if necessary . the technique of the ureteroneocystostomy consisted of an end - to - side extravesical implantation of the ureter onto the anterior bladder wall , modified from the lich - gregoire procedure . in summary , a cc . 1.5 cm incision of detrusor was made on the posterolateral aspect of bladder , followed by sharp dissection of mucosa . the anastomosis was constructed between the spatulated distal donor ureter and a small bladder mucosal nick made after myotomy incision . a watertight mucosa - to - mucosa anastomosis , using 5/0 or 6/0 absorbable running sutures was performed of the spatulated ureter to a distal mucosal opening , followed by the creation of submucosal tunnel by approximation of seromuscular layers using absorbable sutures . data are given as counts ( with percentages ) or mean values ( with sds ) . medians ( with interquartile ranges [ iqr ] ) are reported for non - normally distributed data . for univariate comparisons between the groups , we used chi - square or fisher 's exact test for categorical variables , and by student 's t or mann whitney rank sum test for continuous variables . a logistic regression model was developed to predict urinary tract infection , using various demographic and medical variables as covariates . by stepwise backward selection , non - predictive variables were eliminated using a threshold of p < 0.1 . the explanatory power of the final model was examined by calculating nagelkerke 's rcoefficient , which ranges between 0 ( no predictive power at all ) and 1 ( uti incidence predictable with 100% certainty ) . this is a retrospective , observational study of deceased donor renal allograft recipients who were consecutively transplanted at university hospital essen , germany between january 2002 and december 2006 ( n = 310 ) . data for this study were obtained from our transplant database and review of electronic and paper - based medical records . all adult ( > 18 years ) deceased donor kidney transplantations , except combined multiorgan transplants were considered . living donor transplantations double - j ureteral catheters were placed intraoperatively per the surgeon 's discretion based on ureter , bladder and anastomotic characteristics until june 2004 and on routine basis thereafter . 157 patients were enrolled to a stent- ( st ) and 153 patients to a no - stent ( nst ) group . recipient and donor demographic and laboratory data , at the time of transplantation and afterwards were reviewed . urinary tract infection was defined as the patient having one of the following symptoms dysuria , fever , urgency , frequency , suprapubic tenderness , and positive urine culture with  10microorganism / cmor two of the above signs and pyuria ( > wbc / mm ) or < 105 microorganism / cmif patient was on antibiotics . intravenous cefazoline ( 2 g ) was given once perioperatively within 30 minutes prior to skin incision and repeated once when operation exceeded 3 hours . a dose of single strength trimetoprim / sulfametoxazole ( tmp / smx ) was started on day 2 or 3 and continued every second day for four to six months . all stents were removed by cystoscopy under aseptic conditions 4 - 6 weeks after transplantation . immunosuppression consisted of methylprednisolone ( 500 mg given intraoperatively , followed by sequential tapering to daily oral prednisone 30 mg by one week , 10 mg at one month and 5 mg at 6 - 12 months ) , mycophenolate - mofetil ( 2 g / d postoperatively with dose adjustment for side effects ) , calcineurininhibitors ( tacrolimus or cyclosporin - a started within 24 hours after surgery ) and/or il-2 receptor blockers ( basiliximab , daclizumab ) . estimated glomerular filtration rate ( egfr ) was calculated using the mdrd formula : egfr ( ml / min/1.73 m2 ) = 186  crs-1.154  age-0.203  0.742 ( if female ) . " extra risk " recipients were defined as recipients older than 60 years or older than 50 years with at least one of the following risk factors : coronary heart disease , peripheral arterial disease ( pad , grade iia or higher ) , diabetes mellitus . patients with findings suggestive of uti were hospitalized for further work - up and treatment , if necessary . the technique of the ureteroneocystostomy consisted of an end - to - side extravesical implantation of the ureter onto the anterior bladder wall , modified from the lich - gregoire procedure . in summary , a cc . 1.5 cm incision of detrusor was made on the posterolateral aspect of bladder , followed by sharp dissection of mucosa . the anastomosis was constructed between the spatulated distal donor ureter and a small bladder mucosal nick made after myotomy incision . a watertight mucosa - to - mucosa anastomosis , using 5/0 or 6/0 absorbable running sutures was performed of the spatulated ureter to a distal mucosal opening , followed by the creation of submucosal tunnel by approximation of seromuscular layers using absorbable sutures . data are given as counts ( with percentages ) or mean values ( with sds ) . medians ( with interquartile ranges [ iqr ] ) are reported for non - normally distributed data . for univariate comparisons between the groups , we used chi - square or fisher 's exact test for categorical variables , and by student 's t or mann whitney rank sum test for continuous variables . a logistic regression model was developed to predict urinary tract infection , using various demographic and medical variables as covariates . by stepwise backward selection , non - predictive variables were eliminated using a threshold of p < 0.1 . the explanatory power of the final model was examined by calculating nagelkerke 's rcoefficient , which ranges between 0 ( no predictive power at all ) and 1 ( uti incidence predictable with 100% certainty ) . there was no significant difference between the stented ( st ) and non - stented ( nst ) groups with respect to underlying kidney disease , body mass index ( bmi ) , gender or hla mismatches . the patients from the st group were older , the cold ischemia time was longer and these patients were dialysed longer before transplantation . there was also no significant difference with regard to gender , relevant co - morbidities , cause of death , median length of icu stay or kidney function . one hundred twenty - nine infection episodes of urinary tract infections were diagnosed in 310 ( 41.6% ) recipients . the rate of uti at three months was similar in the st group compared to nst group ( 43.3% vs. 40.1% ) , but without reaching significance ( p = 0.65 ) . the overall rate of urinary tract complications in the two groups were also summarized in table 3 . anastomotic stenosis rate ( 1.3% ) was similar in the nst versus the st group , urinary leakage occurred in 6.8% of all recipients , 8.3% in st- vs. 5.9% in nst group , respectively . we observed fewer episodes of acute rejection in st group ( 22.9% vs. 34.6% , p = 0.024 ) . wound in multivariate analysis ( table 4 ) the following categorical variables had no impact on the rate of uti : age at transplantation , diabetes mellitus , bmi , duration of pretransplant dialysis , duration of surgery and cold ischemia time . however , female gender significantly ( p < 0.001 ) affected the incidence of urinary tract infection ( 54.0% vs. 33.5% , relative risk 1.4 , 95%-ci 1.2 to 1.8 ) . graft function did not differ significantly between the two groups of recipients ( figure 2 ) . clinical results in the two groups . results of multivariate regression analyses of predictors for uti . explanatory power of the final model was limited , as nagelkerke 's r2 was 0.08 . recipient egfr ( in ml/1.73 m ) at transplantation and after 1 , 4 and 52 weeks in the two groups . renal transplantation is a widely accepted treatment for patients with end - stage kidney disease . despite of well established surgical technique and a continuous improvements in patient and graft survival over the past two decades , the rate of urinary tract complications remains still considerable common and may vary between 2 - 15% . these include urinary leak , obstruction , stenosis , necrosis and vesicoureteral re - flux . these complications increase morbidity , delay graft function , and occasionally may lead to graft and/or patient loss . recently , many studies , including a prospective randomized trial , advocate stenting of the ureterovesical anastomosis to reduce the rate of these complication [ 15 - 18 ] . opponents counter that the stent can migrate , could have bad permeability , could contribute to postoperative pain and stone formation . others advocate that stent can increase postoperative infection risk , can erode the lumen , can exacerbate long - term stricturing of the anastomosis and the use of stenting should be restricted to difficult ureterovesical anastomosis . currently , no controlled randomized study evaluated the rate of urinary tract infections with and without ureteral stent implantation , and there is no clearly defined consensus among transplant surgeons with regard to routine stenting of the vesicoureteral anastomosis during renal transplantation . therefore , to further evaluate this issue we conducted a comparative - retrospective study to analyse the frequency of uti in a cohort of deceased donor kidney transplant recipients who were operated either with or without double - j placement in our center . we also investigated the influence of stenting on renal function and major ureteric complications ( leakage , obstruction ) . differences in the definition , follow - up period , immunosuppression and the use of antimicrobial prophylaxis could explain this wide range . a recent report showed that stenting of the vesicoureteral anastomosis is a predictor factor for uti after kidney transplantation . our study has also failed to demonstrate an increased risk of uti in stented recipients . other factors that have been also associated with a higher risk of uti in renal transplant recipients include female gender , age , diabetes mellitus the function of the transplanted kidney and prolonged dialysis pre - transplantation . however , except female gender , none of them was independently associated with a higher risk of uti in our study . we did also not find that advanced age would increase the risk of uti in our renal transplant recipients . although earlier reports have noted a higher incidence of uti - related complications such as pyelonephritis and urosepsis , we did also not observe such an increase . we observed a significant decrease in acute rejection rate in the stented patient group ( 22.9% vs 34.6% ) . one speculative explanation could be that stenting allows early decompression of the anastomosis to ensure free drainage despite mucosal oedema , although auxiliary studies could further evaluate this issue . previous published studies report conflicting results whether a history of diabetes increases or does not influence the renal transplant patient 's risk of developing a uti . diabetic patients have been shown to have a higher incidence of significant bacteriuria therefore we expected this trend to continue after renal transplantation . however , we did not find pre - transplant diabetes to be associated with an increased incidence of uti in our renal transplant population . the lack of impact may be due to the overall low incidence of diabetic recipients ( 12.9% ) in our study population . the pathogens isolated from renal transplant recipients with uti have been previously reported to be similar to those causing uti in the general population . a renal transplant series reported recently , that escherichia coli would be the most common uropathogen ( 32% ) and enterococcus isolated in 18% . these observations are in correlation with the data of alangaden et al . identifying first that enterococcus spp first , due to retrospective comparative data analyses and relatively small number of patients we hesitate to draw firm conclusion from the observed associations . secondary , in the first study period ureterovesical stent were rather implanted on a subjective basis when the transplant surgeon experienced an unfavourable anatomy and expected complications . despite these biases , we would conclude that routine use of double - j stents for prophylactic stenting of the ureteroneocystostomy does not affect significantly the rate of urinary tract infection in deceased donor renal transplant recipient population . whether longer duration of stenting , immunosuppression with induction therapy by multiple transplants or living donor transplantation has a further influence on incidence of uti is still unclear . it is therefore prudent to continue monitoring possible relationship between double - j implantation and uti in renal transplant recipients .
objectiveour objective was to evaluate the impact of routine use of double - j stents on the incidence of urinary tract infection after renal transplantation.methodswe conducted a retrospective - comparative single - centre study in 310 consecutive adult deceased donor kidney recipients transplanted from 2002 to 2006 . 
 patients were divided in two groups , with or without urinary stent implantation . to evaluate the predictive factors for uti , donor and recipients pre- and post - transplantation data were analysed . 
 early urological complications and renal function within 12 months of transplantation were included as well.resultsa total of 157 patients were enrolled to a stent ( st ) and 153 patients to a no - stent ( nst ) group . 
 the rate of urinary tract infection at three months was similar between the two groups ( 43.3% st vs. 40.1% nst , p = 0.65 ) . 
 of the identified pathogens enterococcus and escherichia coli were the most common species . 
 in multivariate analysis neither age nor immunosuppressive agents , bmi or diabetes seemed to have influence on the rate of uti . when compared to males , 
 females had a significantly higher risk for uti ( 54.0% vs. 33.5%).conclusionprophylactic stenting of the ureterovesical anastomosis does not increase the risk of urinary tract infection in the early postoperative period .