Urinary Tract Infections in Solid Organ Transplant Recipients

Abstract

Urinary tract infection (UTI) is the most common infection in the renal transplant patient, the majority occurring in the first year following transplantation. Renal transplant patients have higher rates of UTI, hospitalizations and death due to Gram-negative septicemia associated with pyelonephritis, compared with patients on the renal transplant waiting list (1Reis MA Costa RS Ferraz AS Causes of death in renal transplant recipients: A study of 102 autopsies from 1968 to 1991.J R Soc Med. 1995; 88: 24-27PubMed Google Scholar, 2Abbott KC Oliver JD Hypolite I et al.Hospitalizations for bacterial septicemia after renal transplantation in the United States.Am J Nephrol. 2001; 21: 120-127Crossref PubMed Scopus (110) Google Scholar). Single center studies demonstrate that acute pyelonephritis, especially early posttransplant (3Giral M Pascuariello G Karam G et al.Acute graft pyelonephritis and long-term kidney allograft outcome.Kidney Int. 2002; 61: 1880-1886Abstract Full Text Full Text PDF PubMed Scopus (128) Google Scholar), represents a risk factor to long-term kidney graft function but does not affect graft survival at 5 years (4Pelle G Vimont S Levy PP et al.Acute pyelonephritis represents a risk factor impairing long-term kidney graft function.Am J Transplant. 2007; 7: 899-907Crossref PubMed Scopus (210) Google Scholar). Analysis of the United States Renal Data System (USRDS) database however, reveals that late UTI (>6 m after transplantation) is associated with poor renal allograft survival and increased mortality (5Abbott KC Swanson SJ Richter ER et al.Late urinary tract infection after renal transplantation in the United States.Am J Kidney Dis. 2004; 44: 353-362Abstract Full Text Full Text PDF PubMed Scopus (225) Google Scholar). Confounding factors that may contribute to renal allograft injury during UTI in the renal transplant patient include the combined effects of calcineurin-inhibitors with endotoxin (6Bloom ITM Bentley FR Garrison RN Escherichia coli bacteremia exacerbates cyclosporine-induced renal vasoconstriction.J Surg Res. 1993; 54: 510-516Abstract Full Text PDF PubMed Scopus (5) Google Scholar, 7Cosio FG Innes JT Nahman NSJ Mahan JD Ferguson RM Combined nephrotoxic effects of cyclosporine and endotoxin.Transplantation. 1987; 44: 425-428Crossref PubMed Scopus (8) Google Scholar), rejection (8Audard V Amor M Desvaux D et al.Acute graft pyelonephritis: A potential cause of acute rejection in renal transplant.Transplantation. 2005; 80: 1128-1130Crossref PubMed Scopus (56) Google Scholar) and recurrent UTI (5Abbott KC Swanson SJ Richter ER et al.Late urinary tract infection after renal transplantation in the United States.Am J Kidney Dis. 2004; 44: 353-362Abstract Full Text Full Text PDF PubMed Scopus (225) Google Scholar, 9Muller V Becker G Delfs M Albrecht KH Philipp T Heemann U Do urinary tract infections trigger chronic kidney transplant rejection in man?.J Urol. 1998; 159: 1826-1829Crossref PubMed Scopus (78) Google Scholar). Escherichia coli is the most common uropathogen among renal transplant patients, accounting for the majority of bacteriuria and UTI episodes with Enterococcus species, Pseudomonas, coagulase-negative staphylococci, Enterobacter and other organisms (group B streptococci, and Gardnerella vaginalis) also occurring (Figure 1) (4Pelle G Vimont S Levy PP et al.Acute pyelonephritis represents a risk factor impairing long-term kidney graft function.Am J Transplant. 2007; 7: 899-907Crossref PubMed Scopus (210) Google Scholar, 10Alexopoulos E Memmos D Sakellariou G Paschalidou E Kyrou A Papadimitriou M Urinary tract infections after renal transplantation.Drugs Exp Clin Res. 1985; 11: 101-105PubMed Google Scholar, 11Tolkoff-Rubin NE Rubin RH Urinary tract infection in the immunocompromised host. Lessons from kidney transplantation and the AIDS epidemic.Infect Dis Clin North Am. 1997; 11: 707-717Abstract Full Text Full Text PDF PubMed Scopus (83) Google Scholar, 12Lazinska B Ciszek M Rokosz A Sawicka-Grzelak A Paczek L Luczak M Bacteriological urinalysis in patients after renal transplantation.Pol J Microbiol. 2005; 54: 317-321PubMed Google Scholar, 13Chuang P Parikh CR Langone A Urinary tract infections after renal transplantation: A retrospective review at two US transplant centers.Clin Transplant. 2005; 19: 230-235Crossref PubMed Scopus (195) Google Scholar, 14Memikoglu KO Keven K Sengul S Soypacaci Z Erturk S Erbay B Urinary tract infections following renal transplantation: A single-center experience.Transplant Proc. 2007; 39: 3131-3134Crossref PubMed Scopus (54) Google Scholar). Corynebacterium urealyticum is an emerging pathogen that requires selective media, is frequently associated with obstructive uropathy, and is a potentially important uropathogen as it is not susceptible to most conventional oral antibiotics used for treatment of UTI (15Lopez-Medrano F Garcia-Bravo M Morales JM et al.Urinary tract infection due to Corynebacterium urealyticum in kidney transplant recipients: An underdiagnosed etiology for obstructive uropathy and graft dysfunction-results of a prospective cohort study.Clin Infect Dis. 2008; 46: 825-830Crossref PubMed Scopus (50) Google Scholar). Virulence factors, like P. fimbriae, are expressed on the surface of uropathogenic bacteria and facilitate adhesion to uroepithelial surface. E. coli that express P fimbriae account for more than 80% of the isolates from patients with pyelonephritis in the noncompromised host (16Svanborg C Godaly G Bacterial virulence in urinary tract infection.Infect Dis Clin North Am. 1997; 11: 513-529Abstract Full Text Full Text PDF PubMed Scopus (173) Google Scholar) and the majority of pyelonephritis isolates from immunosuppressed patients (17Johnson JR Virulence factors in Escherichia coli urinary tract infection.Clin Microbiol Rev. 1991; 4: 80-128Crossref PubMed Scopus (959) Google Scholar, 18Dowling KJ Roberts JA Kaack MB P-fimbriated Escherichia coli urinary tract infection: A clinical correlation.South Med J. 1987; 80: 1533-1536Crossref PubMed Scopus (47) Google Scholar). In addition, a subset of O antigen serotypes are present on the majority (80%) of E. coli isolates from patients with UTI (11Tolkoff-Rubin NE Rubin RH Urinary tract infection in the immunocompromised host. Lessons from kidney transplantation and the AIDS epidemic.Infect Dis Clin North Am. 1997; 11: 707-717Abstract Full Text Full Text PDF PubMed Scopus (83) Google Scholar, 19Vaisanen-Rhen V Elo J Vaisanen E et al.P-fimbriated clones among uropathogenic Escherichia coli strains.Infect Immun. 1984; 43: 149-155Crossref PubMed Google Scholar). Although most studies document a decreased prevalence of virulence factors expressed by uropathogenic E. coli from compromised hosts, likely reflecting the weaker barriers to infection in this population (17Johnson JR Virulence factors in Escherichia coli urinary tract infection.Clin Microbiol Rev. 1991; 4: 80-128Crossref PubMed Scopus (959) Google Scholar), a recent report suggests that unique patterns of uropathogenic of O:H serotypes and P fimbriae adherence factor among E. coli isolates from renal transplant patients with UTI (20Rice JC Peng T Kuo Yf et al.Renal allograft injury is associated with urinary tract infection caused by Escherichia coli bearing adherence factors.Am J Transplant. 2006; 6: 2375-2383Crossref PubMed Scopus (70) Google Scholar). The most frequently reported patient and graft characteristics associated with susceptibility to UTI in the renal transplant patients include female gender (4Pelle G Vimont S Levy PP et al.Acute pyelonephritis represents a risk factor impairing long-term kidney graft function.Am J Transplant. 2007; 7: 899-907Crossref PubMed Scopus (210) Google Scholar), recipients of cadaveric kidneys (13Chuang P Parikh CR Langone A Urinary tract infections after renal transplantation: A retrospective review at two US transplant centers.Clin Transplant. 2005; 19: 230-235Crossref PubMed Scopus (195) Google Scholar), recipients of kidney–pancreas transplants (5Abbott KC Swanson SJ Richter ER et al.Late urinary tract infection after renal transplantation in the United States.Am J Kidney Dis. 2004; 44: 353-362Abstract Full Text Full Text PDF PubMed Scopus (225) Google Scholar), prolonged bladder catheterization (21Hoy WE Kissel SM Freeman RB Sterling Jr, WA Altered patterns of posttransplant urinary tract infections associated with perioperative antibiotics and curtailed catheterization.Am J Kidney Dis. 1985; 6: 212-216Abstract Full Text PDF PubMed Scopus (15) Google Scholar) or uretero-vesical stenting (22Tavakoli A Surange RS Pearson RC Parrott NR Augustine T Riad HN Impact of stents on urological complications and health care expenditure in renal transplant recipients: Results of a prospective, randomized clinical trial.J Urol. 2007; 177: 2260-2264Crossref PubMed Scopus (98) Google Scholar) and overall net state of immunosuppression (23Fishman JA Rubin RH Infection in Organ-Transplant Recipients.N Engl J Med. 1998; 338: 1741-1751Crossref PubMed Scopus (1357) Google Scholar) (Table 1). Whether specific immunosuppressive agents are more likely to encourage UTI is unclear, although mycophenolic acid may predispose to UTI and pyelonephritis (24Keven K Sahin M Kutlay S et al.Immunoglobulin deficiency in kidney allograft recipients: Comparative effects of mycophenolate mofetil and azathioprine.Transplant Infect Dis. 2003; 5: 181-186Crossref PubMed Scopus (56) Google Scholar, 25Kamath NS John GT Neelakantan N Kirubakaran MG Jacob CK Acute graft pyelonephritis following renal transplantation.Transpl Infect Dis. 2006; 8: 140-147Crossref PubMed Scopus (127) Google Scholar). Vesico-ureteral reflux (VUR) is common in the renal transplant recipient and children with VUR have an increased risk of acute pyelonephritis (26Ranchin B Chapuis F Dawhara M et al.Vesicoureteral reflux after kidney transplantation in children.Nephrol Dial Transplant. 2000; 15: 1852-1858Crossref PubMed Scopus (65) Google Scholar) and allograft scarring (27Coulthard MG Keir MJ Reflux nephropathy in kidney transplants, demonstrated by dimercaptosuccinic acid scanning.Transplantation. 2006; 82: 205-210Crossref PubMed Scopus (49) Google Scholar). In adults, UTI is not more common in patients with VUR (28Mathew TH Kincaid-Smith P Vikraman P Risks of vesicoureteric reflux in the transplanted kidney.N Engl J Med. 1977; 297: 414-418Crossref PubMed Scopus (76) Google Scholar). However, adult renal transplant patients with late UTI and VUR are prone to allograft scarring (29Dupont PJ Psimenou E Lord R Buscombe JR Hilson AJ Sweny P Late recurrent urinary tract infections may produce renal allograft scarring even in the absence of symptoms or vesicoureteric reflux.Transplantation. 2007; 84: 351-355Crossref PubMed Scopus (80) Google Scholar).Table 1Major risk factors for bacterial urinary tract infection, candiduria and pyelonephritis in renal transplant recipientsRisk factor (references)OR (95% CI)Bacterial urinary tract infection (13Chuang P Parikh CR Langone A Urinary tract infections after renal transplantation: A retrospective review at two US transplant centers.Clin Transplant. 2005; 19: 230-235Crossref PubMed Scopus (195) Google Scholar, 24Keven K Sahin M Kutlay S et al.Immunoglobulin deficiency in kidney allograft recipients: Comparative effects of mycophenolate mofetil and azathioprine.Transplant Infect Dis. 2003; 5: 181-186Crossref PubMed Scopus (56) Google Scholar, 54Dantas SR Kuboyama RH Mazzali M Moretti ML Nosocomial infections in renal transplant patients: Risk factors and treatment implications associated with urinary tract and surgical site infections.J Hosp Infect. 2006; 63: 117-123Abstract Full Text Full Text PDF PubMed Scopus (96) Google Scholar, 57Lapchik MS Castelo FA Pestana JO Silva Filho AP Wey SB Risk factors for nosocomial urinary tract and postoperative wound infections in renal transplant patients: A matched-pair case-control study.J Urol. 1992; 147: 994-998Crossref PubMed Scopus (19) Google Scholar)Female gender5.8 (3.79–8.89)Age (per year)0.02 (1.01–1.04)Reflux kidney disease prior to transplantation3.0 (1.05–8.31)Deceased donor3.64 (1.0–12.7)Duration of bladder catheterization1.50 (1.1–1.9)\Length of hospitalization prior to UTI0.92 (0.88–0.96)Increase in immunosuppression17.04 (4.0–71.5)Candiduria (30Safdar N Slattery WR Knasinski V et al.Predictors and outcomes of candiduria in renal transplant recipients.Clin Infect Dis. 2005; 40: 1413-1421Crossref PubMed Scopus (115) Google Scholar)Female gender12.5 (6.70–23.0)ICU care8.8 (2.3–35.0)Prior antibiotic use3.8 (1.7–8.3)Indwelling urethral catheter4.4 (2.1–9.4)Neurogenic bladder7.6 (2.1–27)Malnutrition2.4 (1.3–4.4)Acute pyelonephritis (4Pelle G Vimont S Levy PP et al.Acute pyelonephritis represents a risk factor impairing long-term kidney graft function.Am J Transplant. 2007; 7: 899-907Crossref PubMed Scopus (210) Google Scholar, 25Kamath NS John GT Neelakantan N Kirubakaran MG Jacob CK Acute graft pyelonephritis following renal transplantation.Transpl Infect Dis. 2006; 8: 140-147Crossref PubMed Scopus (127) Google Scholar)Female gender5.14 (1.86–14.20)Acute rejection episodes3.84 (1.37–10.79)Number of UTIs1.17 (1.06–1.30)Mycophenolate mofetil1.9 (1.2–2.3)NR, not reported. Open table in a new tab NR, not reported. Candida species are among the most common fungal causes of UTI in persons who have undergone renal transplantation. While candiduria is frequent, occurring in 11% of renal transplant patients in one series (30Safdar N Slattery WR Knasinski V et al.Predictors and outcomes of candiduria in renal transplant recipients.Clin Infect Dis. 2005; 40: 1413-1421Crossref PubMed Scopus (115) Google Scholar), it is most often asymptomatic. Although most risk factors for candiduria are similar to those predisposing to bacterial UTI, important differences include the close association of candiduria with prior antibiotic use and severe illness requiring ICU care. The incidence of UTI in immunosuppressed patients, including solid organ transplants other than renal transplant patients, is not higher than nonimmunosuppressed individuals (31Korzeniowski OM Urinary tract infection in the impaired host.Med Clin North Am. 1991; 75: 391-404Crossref PubMed Scopus (18) Google Scholar). The addition of a pancreas transplant to a kidney transplant is associated with frequent UTIs, especially when exocrine secretions are drained into the bladder. The frequency of UTIs are significantly less when exocrine pancreas secretions are drained enterically (32Pirsch JD Odorico JS D’Alessandro AM Knechtle SJ Becker BN Sollinger HW Posttransplant infection in enteric versus bladder-drained simultaneous pancreas-kidney transplant recipients.Transplantation. 1998; 66: 1746-1750Crossref PubMed Scopus (85) Google Scholar, 33Stratta RJ Shokouh-Amiri MH Egidi MF et al.A prospective comparison of simultaneous kidney-pancreas transplantation with systemic-enteric versus portal-enteric drainage.Ann Surg. 2001; 233: 740-751Crossref PubMed Scopus (77) Google Scholar). The diagnosis of a symptomatic UTI requires a quantitative count of bacteria (≥105) in an appropriately collected urine specimen in the presence of symptoms or signs of urinary infection (34Rubin RH Shapiro ED Andriole VT Davis RJ Stamm WE Evaluation of new anti-infective drugs for the treatment of urinary tract infection. Infectious Diseases Society of America and the Food and Drug Administration.Clin Infect Dis. 1992; 15: S216-S227Crossref PubMed Scopus (390) Google Scholar). However, the RTP may not present with classic symptoms of UTI and the lack of symptoms is an important distinguishing feature of UTI in the renal allograft recipient (35Ramsey DE Finch WT Birtch AG Urinary Tract Infections in kidney transplant recipients.Arch Surg. 1979; 114: 1022-1025Crossref PubMed Scopus (47) Google Scholar). The majority of renal transplant recipients with bacteriuria do not have symptoms with their UTI, hence have ‘asymptomatic bacteriuria’ (ASB) (36Takai K Tollemar J Wilczek HE Groth CG Urinary tract infections following renal transplantation.Clin Transplant. 1998; 12: 19-23PubMed Google Scholar, 37Nicolle LE Bradley S Colgan R Rice JC Schaeffer A Hooton TMal Infectious Diseases Society of America guidelines for the diagnosis and treatment of asymptomatic bacteriuria in adults.Clin Infect Dis. 2005; 40: 643-654Crossref PubMed Scopus (1200) Google Scholar). Renal transplant patients with ASB have biochemical evidence of local inflammation, as urinary cytokine levels are higher than in transplant patients without bacteriuria and are more likely to develop symptomatic UTI within the next year (38Ciszek M Paczek L Bartlomiejczyk I et al.Urine cytokines profile in renal transplant patients with asymptomatic bacteriuria.Transplantation. 2006; 81: 1653-1657Crossref PubMed Scopus (29) Google Scholar). ‘Acute cystitis’ is a symptomatic infection of the lower bladder with frequency, urgency, dysuria or suprapubic pain sometimes accompanied by low-grade fever <38.3°C, but without flank pain or renal allograft tenderness. ‘Acute pyelonephritis’ is an infection of the upper urinary tract or renal parenchyma, characterized by costovertebral angle pain (if native kidneys involved) or renal allograft tenderness (if transplanted kidney involved) often with fever ≥38.3°C. ‘Complicated UTI’ is an infection in individuals with functional or structural abnormalities of the genitourinary tract and that may involve either the bladder or kidneys (39Stamm WE Hooton TM Management of urinary tract infections in adults.N Engl J Med. 1993; 329: 1328-1334Crossref PubMed Scopus (736) Google Scholar). Hence, all UTIs in the renal transplant patient should be considered complicated UTIs, due to functional (immunosuppression) and structural abnormalities (resulting from uretero-neocystostomy). The prevalence of resistance to other antibiotics among uropathogenic bacteria is increasing (40Hooton TM Besser R Foxman B Fritsche TR Nicolle LE Acute uncomplicated cystitis in an era of increasing antibiotic resistance: A proposed approach to empirical therapy.Clin Infect Dis. 2004; 39: 75-80Crossref PubMed Scopus (165) Google Scholar, 41Multiply antibiotic-resistant Gram-negative bacteria.Am J Transplant. 2004; 4: 21-24Crossref PubMed Scopus (6) Google Scholar, 42Killgore KM March KL Guglielmo BJ Risk factors for community-acquired ciprofloxacin-resistant Escherichia coli urinary tract infection.Ann Pharmacother. 2004; 38: 1148-1152Crossref PubMed Scopus (90) Google Scholar), resulting in the rapid emergence of multidrug resistant strains and a higher incidence of treatment failure and re-infection (43Hooton TM Recurrent urinary tract infection in women.Int J Antimicrob Agents. 2001; 17: 259-268Crossref PubMed Scopus (325) Google Scholar). The prevalence of drug resistance varies considerably by region and country, thus, awareness of local and regional antibiotic susceptibility among uropathogens is recommended to optimize empiric treatment. While the general principles of antibiotic treatment of asymptomatic bacteriuria, cystitis and acute pyelonephritis are similar in transplant and nontransplant patients, several important distinctions deserve mention (44Warren JW Abrutyn E Hebel JR Johnson JR Schaeffer AJ Stamm WE Guidelines for antimicrobial treatment of uncomplicated acute bacterial cystitis and acute pyelonephritis in women. Infectious Diseases Society of America (IDSA).Clin Infect Dis. 1999; 29: 745-758Crossref PubMed Scopus (992) Google Scholar, 45Munoz P Management of urinary tract infections and lymphocele in renal transplant recipients.Clin Infect Dis. 2001; 33: S53-S57Crossref PubMed Scopus (88) Google Scholar). There is not a consensus whether ASB, the isolation of bacteria (≥105) in an appropriately collected urine specimen in the absence of symptoms or signs of urinary infection, should be treated in the transplant patient and if so, at what time points posttransplant (37Nicolle LE Bradley S Colgan R Rice JC Schaeffer A Hooton TMal Infectious Diseases Society of America guidelines for the diagnosis and treatment of asymptomatic bacteriuria in adults.Clin Infect Dis. 2005; 40: 643-654Crossref PubMed Scopus (1200) Google Scholar). A prospective randomized trial does suggest that treatment of ASB beyond one year does not prevent symptomatic UTI (46Moradi M Abbasi M Moradi A Boskabadi A Jalali A Effect of antibiotic therapy on asymptomatic bacteriuria in kidney transplant recipients.Urol J. 2005; 2: 32-35PubMed Google Scholar). Historically, prolonged therapy for early UTI infections (within the first 3 months of transplant) was recommended because of the risk of pyelonephritis, bacteremia and graft loss based on noncomparative studies (47Rubin RH Fang LS Cosimi AB et al.Usefulness of the antibody-coated bacteria assay in the management of urinary tract infection in the renal transplant patient.Transplantation. 1979; 27: 18-20Crossref PubMed Scopus (21) Google Scholar). However, with advancement in surgical techniques and the availability of more potent effective antimicrobials in recent years, prolonged therapy is not considered necessary for first episodes of UTI. A Gram stain of a urine specimen should be performed to guide therapy. An oral fluoroquinolone may be used empirically. If there is evidence of Gram-positive cocci on Gram stain, coverage for enterococcus with amoxicillin should be added until the causative organism is identified. For patients that require initial parenteral therapy because of severe illness or nausea and vomiting, beta-lactams such as ceftriaxone or a fluoroquinolone may be used. The duration of therapy has not been specifically studied in transplant patients. In nontransplant patients, a 7–14 day course is recommended; a short course (3-day) treatment of UTI has not been studied in transplant patients and is not recommended. Imaging of the genitourinary tract should be undertaken in transplant patients who continue to have persistent symptoms despite appropriate therapy to evaluate for complicated pyelonephritis. Progression of upper urinary tract disease, to a nephric or perinephric abscess or emphysematous pyelonephritis may occur and usually requires a multidisciplinary approach to treatment, including urologic and/or interventional radiology consultation for percutaneous or surgical drainage of abscesses. Broad-spectrum anti-infective therapy should be initiated, with a carbapenem, extended spectrum penicillin, or third generation cephalosporin. Duration of treatment should be at least 2 weeks and should be extended until adequate drainage of abscesses has been achieved. Anatomic abnormalities must be excluded in renal transplant patients with a relapsing UTI. In the face of a relapsing UTI in a renal transplant recipient, the most common findings include vesico-ureteral reflux, strictures at the ureterovesical junction and neurogenic bladder (45Munoz P Management of urinary tract infections and lymphocele in renal transplant recipients.Clin Infect Dis. 2001; 33: S53-S57Crossref PubMed Scopus (88) Google Scholar). Further research is necessary to determine whether asymptomatic candiduria warrants treatment in renal transplant patients, as data on treatment of candiduria in renal transplantation is scant. In one observational case control study of 192 renal transplant recipients with candiduria, 50% were not treated with antifungal therapy. Treatment of asymptomatic candiduria was not associated with improved clinical outcomes (30Safdar N Slattery WR Knasinski V et al.Predictors and outcomes of candiduria in renal transplant recipients.Clin Infect Dis. 2005; 40: 1413-1421Crossref PubMed Scopus (115) Google Scholar). Many asymptomatic patients with candiduria are treated because of the perceived risk to the allograft and the potential for involvement of the upper urinary tract. Hence, recent guidelines from the Infectious Diseases Society of America recommend treatment of candiduria in patients with renal allografts, preferably with fluconazole, 200 mg orally per day for 7–14 days or intravenous amphotericin B, 0.3–1 mg/kg/day for 1–7 days; bladder irrigation with amphotericin B is of limited value (48Pappas PG Rex JH Sobel JD et al.Guidelines for treatment of candidiasis.Clin Infect Dis. 2004; 38: 161-189Crossref PubMed Scopus (1262) Google Scholar). The echinocandins achieve low concentrations in the urinary tract, which precludes their use for treatment of fungal urinary tract infection. Removal (preferred) or replacement of urinary tract instruments such as urologic stents and urethral catheters is recommended. Prevention of both ASB and UTI posttransplant improved with the introduction of routine perioperative antibiotic prophylaxis, minimization of use of indwelling urethral catheters and long-term use of antimicrobial prophylaxis to prevent pneumonia and other infections (21Hoy WE Kissel SM Freeman RB Sterling Jr, WA Altered patterns of posttransplant urinary tract infections associated with perioperative antibiotics and curtailed catheterization.Am J Kidney Dis. 1985; 6: 212-216Abstract Full Text PDF PubMed Scopus (15) Google Scholar, 49Fox BC Sollinger HW Belzer FO Maki DG A prospective, randomized, double-blind study of trimethoprim-sulfamethoxazole for prophylaxis of infection in renal transplantation: Clinical efficacy, absorption of trimethoprim-sulfamethoxazole, effects on the microflora, and the cost-benefit of prophylaxis.Am J Med. 1990; 89: 255-274Abstract Full Text PDF PubMed Scopus (202) Google Scholar). Studies published more than 15 years ago demonstrated that prophylaxis with trimethoprim-sulfamethoxazole (TMP-SMX) reduced the risk of UTI three-fold, did not result in significant colonization by TMP-SMZ resistant Gram-negative bacilli (49Fox BC Sollinger HW Belzer FO Maki DG A prospective, randomized, double-blind study of trimethoprim-sulfamethoxazole for prophylaxis of infection in renal transplantation: Clinical efficacy, absorption of trimethoprim-sulfamethoxazole, effects on the microflora, and the cost-benefit of prophylaxis.Am J Med. 1990; 89: 255-274Abstract Full Text PDF PubMed Scopus (202) Google Scholar, 50Tolkoff-Rubin NE Cosimi AB Russell PS Rubin RH A controlled study of trimethoprim-sulfamethoxazole prophylaxis of urinary tract infection in renal transplant recipients.Rev Infect Dis. 1982; 4: 614-618Crossref PubMed Scopus (99) Google Scholar), and led to recommendations for use of prophylactic antibiotics (TMP-SMX) for 6 months–1 year posttransplant (45Munoz P Management of urinary tract infections and lymphocele in renal transplant recipients.Clin Infect Dis. 2001; 33: S53-S57Crossref PubMed Scopus (88) Google Scholar). As uropathogenic bacteria have become more TMP-SMX resistant (40Hooton TM Besser R Foxman B Fritsche TR Nicolle LE Acute uncomplicated cystitis in an era of increasing antibiotic resistance: A proposed approach to empirical therapy.Clin Infect Dis. 2004; 39: 75-80Crossref PubMed Scopus (165) Google Scholar, 41Multiply antibiotic-resistant Gram-negative bacteria.Am J Transplant. 2004; 4: 21-24Crossref PubMed Scopus (6) Google Scholar), prophylaxis with TMP-SMX may be less effective for the prevention of UTI in transplant recipients. Although antibiotic prophylaxis remains the standard-of-care in most renal transplant programs (51Batiuk TD Bodziak KA Goldman M Infectious disease prophylaxis in renal transplant patients: A survey of US transplant centers.Clinical Transplantation. 2002; 16: 1-8Crossref PubMed Scopus (44) Google Scholar), no recent guidelines address the optimal drug, dose or duration of antibiotic prophylaxis or antibiotic susceptibility of UTI isolates in the posttransplant population (52Kasiske BL Vazquez MA Harmon WE et al.Recommendations for the outpatient surveillance of renal transplant recipients. American Society of Transplantation.J Am Soc Nephrol. 2000; 11: S1-S86Crossref PubMed Google Scholar). As earlier reports did not demonstrate a clear association between UTI and impaired renal allograft survival, unless the UTI occurred within 3 months after transplantation (3Giral M Pascuariello G Karam G et al.Acute graft pyelonephritis and long-term kidney allograft outcome.Kidney Int. 2002; 61: 1880-1886Abstract Full Text Full Text PDF PubMed Scopus (128) Google Scholar) or was associated with a urological complication (53Lyerova L Lacha J Skibova J Teplan V Vitko S Schuck O Urinary tract infection in patients with urological complications after renal transplantation with respect to long-term function and allograft survival.Ann Transplant. 2001; 6: 19-20PubMed Google Scholar), screening for UTI has been recommended for renal transplant recipients only in the early months (<6 m) posttransplant. Recent guidelines from the Infectious Disease Society of American acknowledge that at present, ‘no recommendations can be made for screening for or treatment of ASB in renal transplant or other solid organ transplant recipients’ (37Nicolle LE Bradley S Colgan R Rice JC Schaeffer A Hooton TMal Infectious Diseases Society of America guidelines for the diagnosis and treatment of asymptomatic bacteriuria in adults.Clin Infect Dis. 2005; 40: 643-654Crossref PubMed Scopus (1200) Google Scholar). Future studies are needed to determine: (1) the clinical consequences and appropriate treatment strategy for ASB in the renal and nonrenal transplant recipient, (2) the prevalence of antibiotic-resistant uropathogens in the renal transplant population (3) if the increased antibiotic resistance of uropathogenic bacteria contributes to increased infection rates and potentially, limits long-term renal allograft function and (4) whether symptomatic candiduria warrants treatment in transplant patients. The increase in resistance to antiinfectives noted among uropathogens in renal transplant patients has important implications for healthcare institutions. Nosocomial cross-transmission of resistant Gram-negative pathogens has been reported (54Dantas SR Kuboyama RH Mazzali M Moretti ML Nosocomial infections in renal transplant patients: Risk factors and treatment implications associated with urinary tract and surgical site infections.J Hosp Infect. 2006; 63: 117-123Abstract Full Text Full Text PDF PubMed Scopus (96) Google Scholar). Healthcare workers should use contact isolation precautions for patients, known to be colonized with resistant organisms. It is unknown whether microbiologic surveillance for the presence of resistant uropathogens is beneficial in preventing transmission. Limiting the duration of urinary tract instrumention to the minimum necessary reduces the risk of UTI in the renal transplant patient (49Fox BC Sollinger HW Belzer FO Maki DG A prospective, randomized, double-blind study of trimethoprim-sulfamethoxazole for prophylaxis of infection in renal transplantation: Clinical efficacy, absorption of trimethoprim-sulfamethoxazole, effects on the microflora, and the cost-benefit of prophylaxis.Am J Med. 1990; 89: 255-274Abstract Full Text PDF PubMed Scopus (202) Google Scholar). Specific recommendations: (1)Limit duration of urinary tract instrumentation, including catheters and uretero-vesicle stents, in renal transplant patients. [I] (21Hoy WE Kissel SM Freeman RB Sterling Jr, WA Altered patterns of posttransplant urinary tract infections associated with perioperative antibiotics and curtailed catheterization.Am J Kidney Dis. 1985; 6: 212-216Abstract Full Text PDF PubMed Scopus (15) Google Scholar, 22Tavakoli A Surange RS Pearson RC Parrott NR Augustine T Riad HN Impact of stents on urological complications and health care expenditure in renal transplant recipients: Results of a prospective, randomized clinical trial.J Urol. 2007; 177: 2260-2264Crossref PubMed Scopus (98) Google Scholar)(2)Antibiotic prophylaxis is recommended during the first 3–6 months posttransplant with either TMP-SMX or ciprofloxacin, despite high levels of antibiotic resistance to TMP-SMX. [I] (49Fox BC Sollinger HW Belzer FO Maki DG A prospective, randomized, double-blind study of trimethoprim-sulfamethoxazole for prophylaxis of infection in renal transplantation: Clinical efficacy, absorption of trimethoprim-sulfamethoxazole, effects on the microflora, and the cost-benefit of prophylaxis.Am J Med. 1990; 89: 255-274Abstract Full Text PDF PubMed Scopus (202) Google Scholar, 50Tolkoff-Rubin NE Cosimi AB Russell PS Rubin RH A controlled study of trimethoprim-sulfamethoxazole prophylaxis of urinary tract infection in renal transplant recipients.Rev Infect Dis. 1982; 4: 614-618Crossref PubMed Scopus (99) Google Scholar, 55Hibberd PL Tolkoff-Rubin NE Doran M et al.Trimethoprim-sulfamethoxazole compared with ciprofloxacin for the prevention of urinary tract infection in renal transplant recipients. A double-blind, randomized controlled trial.Online J Curr Clin Trials. 1992; 15 (Doc No 15)Google Scholar)(3)Urine cultures are needed to confirm infection, identify the bacterial strain and determine antibiotic sensitivity, due to high levels of antibiotic resistance of urinary isolates in the transplant population. [I] (41Multiply antibiotic-resistant Gram-negative bacteria.Am J Transplant. 2004; 4: 21-24Crossref PubMed Scopus (6) Google Scholar)(4)No recommendations can be made about diagnosis or treatment of asymptomatic bacteriuria or candiduria in the renal allograft recipient. [II] (37Nicolle LE Bradley S Colgan R Rice JC Schaeffer A Hooton TMal Infectious Diseases Society of America guidelines for the diagnosis and treatment of asymptomatic bacteriuria in adults.Clin Infect Dis. 2005; 40: 643-654Crossref PubMed Scopus (1200) Google Scholar)(5)Any UTI in a renal transplant patient should be considered a complicated UTI and diagnosis and management should be undertaken with these factors under consideration. [III].(6)There are no data to support short-term treatment of UTI in the transplant patient, hence short-term treatment is not recommended. [III] The authors have nothing to disclose.