Urinary tract infections in renal transplant recipients

Urinary tract infection (UTI) is the most common infectious complication following renal transplantation. The purposes of this study were to determine the causative agents of UTIs among renal transplant recipients and to compare the antibiotic susceptibilities of Escherichia coli strains isolated from renal transplant recipients and complicated community-acquired UTIs. We evaluated 75 episodes of 63 recipients with confirmed UTI who underwent transplantation during the period 1981 to 2006 at our center. Medical records of the patients were reviewed retrospectively. To compare the susceptibility rates of E coli, 226 isolates from nontransplant patients with complicated community-acquired UTIs were also evaluated. Ten episodes (13.3%) occurred in the first month following the transplantation, 11 (14.7%) in the period of the second month to the sixth month, and 54 (72%) after the sixth month of transplantation. Forty-six (61.3%) isolates were E coli. Among these isolates, ciprofloxacin resistance rates were 50% (2/4) in the first month after transplantation, 75% (6/8) in the period of the second month to the sixth month, and 32.4% (11/34) beyond 6 months after transplantation. The resistance rates of trimethoprim/sulfamethoxazole (TMP-SMX) in the same time periods were 100% (4/4), 87.5% (7/8), and 70.6% (24/34), respectively. The rates of resistance to TMP-SMX among E coli isolated from renal recipients were significantly higher than those in community-acquired complicated UTIs. The increased resistance of urinary pathogens to this agent is a major concern. Although high resistance rates of ciprofloxacin against E coli strains were determined in this group, it was not found to be statistically significant.     

Urinary tract infections in renal transplant recipients

Introduction

Urinary tract infections (UTIs) are most common infections in renal transplant recipients and are considered a potential risk factor for poorer graft outcomes.

Aim

To evaluate incidence, clinical manifestations, microbiology, risk factors for UTIs, and the influence of UTIs on long-term renal graft function.

Patients and methods

We analyzed urine cultures with reference to clinical data of patients who received a renal transplantation from January to December 2009 with a 12-month follow-up.

Results

The 1170 urine cultures were correlated with clinical data from 89 renal transplant recipients, including 58.4% males and on overall mean age of 48 ± 14 years. The 151 episodes in 49 patients consisted of asymptomatic bacteriuria (65%, n = 98); lower UTIs (13%, n = 19); and upper UTIs (22%, n = 34), as well as five cases of bacteremia. Nearly 48% of UTIs were diagnosed during the first month posttransplantation. The most frequently isolated uropathogens were Enterococcus faecium (33%, n = 24) and Escherichia coli (31%, n = 23). Beginning from the second month, most frequently found bacterium in urine cultures was E coli (65% n = 51). Risk factors for posttransplant UTIs were female gender and a history of an acute rejection episode and/or a cytomegalovirus (CMV) infection. All patients with vesicoureteral reflux of strictures at the ureterovesical junction suffered recurrent UTIs (n = 7). The evolution of renal graft function did not differ significantly between patients with versus without UTIs.

Conclusions

UTIs a frequent problem after kidney transplantation most commonly exist as asymptomatic bacteriuria. E coli and E faecium are ther predominant pathogens. Exposure to intensified immunosuppression due to acute rejection episodes or CMV infections represents a risk factor for UTIs. Vesicoureteral reflux or strictures at the ureterovesical junction are risk factors for recurrent UTIs. UTIs did not impair 1-year graft function.     

Urinary tract infection in pediatric renal transplantation

Urinary tract infection is a frequent complication following renal transplantation and represents a potential focus for systemic infection in the immunosuppressed transplant recipient. The incidence, etiologic factors, temporal pattern, bacteriology, and prognostic significance of urinary tract infection were determined by analysis of 85 renal allografts in 69 patients. Significant bacteriuria occurred after 49 of 85 transplants (58 per cent). The incidence of infection was not related to success or source of the allograft, but was related to patient gender. Urinary tract infections developed in 68 per cent of females, while only 43 per cent of males became infected (p < 0.05). Escherichia coli caused most first infections (30 per cent), while Pseudomonas aeruginosa and E. coli were equally responsible for recurrent infections (25 per cent each). Children with previous reconstructive urologic surgery had similar allograf success (63 per cent) and infection rates (53 per cent) as our other children (61 per cent and 58 per cent, respectively). No apparent correlation was noted between episodes of infection and graft rejection. Thorough preoperative assessment and preparation and prompt, specific treatment minimize the adverse influences of urinary tract infection.     

Urinary tract infection after renal transplantation

Eighty-eight patients with cadaver and living donor kidney transplants and the incidence of urinary tract infections over a long-term follow-up period are reviewed. Urinary tract infections developed in 28 per cent of the 88 patients after renal transplantation, and 72 per cent of these infections developed within the first month of transplantation. Only 43 per cent of the infecting organisms were Escherichia coli. Forty-seven per cent of the patients with recurrent urinary tract infections had pyelonephritis or polycystic kidneys as their original renal disease. The morbidity rate in our patients with recurrent urinary tract infections was minimal.     

Urinary tract infection in percutaneous surgery for renal calculi

Percutaneous extraction of renal stones is associated with a risk of infection, which sometimes can be severe as a result of the intraoperative introduction of a ureteral catheter, the nephroscopy itself and the fact that a nephrostomy tube sometimes is left in place. It generally is accepted that patients with a preoperative urinary tract infection should be covered during the operation by an appropriate antibiotic. However, the need for routine prophylactic antibiotic treatment in patients with sterile urine preoperatively still is a subject of debate. We report the bacteriological results of 126 cases of percutaneous extraction of renal stones. Of the patients 107 had sterile urine preoperatively and deliberately did not receive prophylactic antibiotics so that the mechanisms of urinary tract infection after percutaneous nephrolithotomy could be studied. Of these patients 37 (35 per cent) suffered a postoperative urinary tract infection, usually owing to Escherichia coli, streptococcus or staphylococcus. The responsible organism was isolated in the bladder urine only in 22 cases, in the nephrostomy tube in 2 and in both sites in 13. Eleven patients (10 per cent) presented with a fever of 38.5C or more. All of the infected patients received appropriate antibiotic therapy and there were only 2 bacteriological failures on long-term followup (5 per cent). A total of 19 patients had a urinary tract infection preoperatively. All 19 patients received appropriate antibiotic therapy starting at least 24 hours preoperatively and continuing for a minimum of 3 weeks. Five patients (26 per cent) presented with a fewer but there were no serious septic complications. All of the patients were discharged from the hospital with sterile urine and there was only 1 long-term bacteriological failure (5 per cent). Both patients with Pseudomonas infection were cured. The risk of clinical infection following percutaneous nephrolithotomy is low despite the fact that 35 per cent of the patients have bacteriuria postoperatively, provided a careful bacteriological examination is performed preoperatively and the patients with urinary tract infection are treated appropriately. These results are in favor of short-term prophylactic antibiotics adapted to the bacterial ecology.     

Urinary tract infection in oliguric patients with chronic renal failure

We studied 182 patients with chronic renal failure by urinalysis and urine cultures. Of the patients 27 per cent had significant bacteriuria (more than 10(5) per ml.), 38 per cent had significant pyuria (more than 10 white blood cells per high power field), 19 per cent had urinary tract infection and 7 per cent had symptomatic urinary tract infection. All 12 patients with symptomatic urinary tract infection had significant bacteriuria and 11 had significant pyuria, while 1 had 5 to 10 white blood cells per high power field. Incidences of urinary tract infection differed depending on the primary renal disease (12, 13, 41 and 67 per cent for chronic glomerulonephritis, diabetic nephropathy, polycystic kidney and chronic pyelonephritis, respectively). Among the patients with chronic glomerulonephritis no significant differences were seen in frequencies of bacteriuria and urinary tract infection between male and female patients or between those who did and did not undergo hemodialysis. Also, no significant correlation was seen between bacteriuria and daily urine output but pyuria was significantly more frequent in oliguric patients or those on hemodialysis.     

Fatal disseminated adenoviral infection in a renal transplant patient

Immunosuppressed patients are more susceptible to adenoviral infection and carry a significantly higher mortality than immunocompetent patients. Renal transplant patients with adenoviral infection most often present with infection of the kidney and urinary tract within weeks to months of transplant surgery, suggesting reactivation of the latent adenovirus in the immunosuppressed host as the source of infection. We describe the first case of a fatal adenovirus infection after several years of immunosuppression in a kidney transplant patient. Postmortem examination of several tissues, using standard viral culture and polymerase chain reaction, was positive for adenovirus serotype 21. This case is unusual in that the fatal disseminated viral infection occurred after 6 years of immunosuppression, suggesting that the source of adenovirus was a novel infection rather than reactivation of latent infection, or infection from the transplanted tissue. Furthermore, this is the first report of adenovirus type 21 in an immunosuppressed patient.     

Urinary tract infection

A model for the experimental production of an ascending chronic infection of urinary tract in rats is described. The traumatic action caused by a stainless steel cylinder filled with a suspension ofP. mirabilis, the slowing-down of the elimination of germs by the urine and the induction of a water diuresis by 5% glucose in the drinkingwater, were suitable in producing a urinary tract disease with bladder and renal stones. The model is fairly reproducible and suitable for studying the activity of drugs against uninary tract infections.     

肾移植术后泌尿系感染的特点分析

目的探讨肾移植术后泌尿系感染的特点。方法回顾性分析2009年1月至12月在暨南大学附属第一医院进行肾移植的38例患者(男性24例,女性14例)的临床资料,对其术后1年内尿常规、尿培养结果及其他临床资料进行总结分析。结果 38例患者肾移植术后1年内共查尿常规次数787例次,其中尿常规阴性结果为633例次,标本污染53例次,细菌尿次数101例次,其中71例次发生肾移植术后半年内。101例次泌尿系感染中,无症状性菌尿为68例次,上尿路感染19例次,下尿路感染14例次,并发脓毒血症者3例次。38例患者中,共有25例(男14例、女11例)患者出现细菌尿,有19例患者出现不少于2次泌尿系感染。最常见的致病菌为大肠埃希菌(36例次),其次是粪肠球菌(26例次)。肾移植术前血液透析患者术后感染率为70%。36例术后7d内拔出尿管和双J管的患者肾移植术后感染率64%,而2例肾移植术后7d后拔出尿管和双J管患者均发生感染。术后出现膀胱输尿管反流的3例患者均出现泌尿系感染。结论肾移植术后泌尿系感染具有高发性、反复发作的特点,最常见的致病菌为大肠埃希菌。女性、尿管和双J管的长时间留置、术后膀胱输尿管反流、术前长时间血液透析等都会诱发肾移植术后的泌尿系感染。     

Continuous sulfa prophylaxis for urinary tract infection in renal transplant recipients

During a 12 to 25 month follow-up period, 252 renal transplant recipients maintained with continuous sulfa prophylaxis were observed for evidence of bacteriuria. Although symptoms were rare, positive cultures were obtained in 6 percent of the patients who responded to conventional antibiotic outpatient therapy. Compared with sulfisoxazole, trimethoprim-sulfamethoxazole led to slightly fewer infections, especially with gram-negative organisms. Toxicity from sulfa was minimal and occasional leukopenia reversed by temporarily withholding azathioprine. Continuous sulfa prophylaxis in renal transplant patients is therefore safe and effective in minimizing the incidence of urinary tract infection, as well as other opportunistic infections known to be treatable by sulfa agents.     

Urinary tract infections in post-renal transplant patients

The overall incidence of urinary tract infections (UTIs) in our renal transplant population was 30.9%, i.e. 0.15 episode per patient-year. UTIs occurred more often within the first 3 months (60%) of transplantation. Fifty per cent of UTIs were asymptomatic. Recurrences were common. Acute tubular necrosis and cellular rejections were important associations. UTIs had little effect on graft function and survival up to 3 years post-transplant.     

Urinary calculi in renal transplant recipients

Urinary calculi are an uncommon complication in renal transplant recipients. During a 15-year period, in 544 cases of kidney transplantation with a functioning allograft for more than 3 months, and a long-term follow-up, we have observed 9 cases (1.7%) of urinary calculi. Calculi occurred in 6 male and 3 female patients, 6 patients were recipients of living related and 3 of cadaveric kidneys. Calculi were diagnosed as early as 3 months and as late as 3.5 years after transplantation, but most were detected within the first year. The location of the calculi was the bladder in 4 cases, the transplant in 3, and indeterminant in 2. Crystallographic analysis of retrieved stones revealed calcium oxalate and/or phosphate in 4 cases, triple phosphate in 2, and uric acid in 1. All patients had one or more stone-predisposing factors, such as obstructive uropathy and recurrent urinary tract infection (4 cases), hyperoxaluria (3), or hypercalciuria (2). During long-term follow-up (mean 60 months), only one patient lost the renal graft, 14.5 years after transplantation, primarily from causes unrelated to urinary calculi. One instance of stone recurrence was noted. In conclusion: (1) urinary calculi after renal transplantation are relatively uncommon; (2) predisposing factors and crystallographic composition of the calculi are identical in type, but not frequency, to those of nontransplant patients; and (3) with proper medical and surgical management, post-transplant urolithiasis does not appear to affect graft prognosis.     

Urinary tract infection in childhood

The importance of establishing significant bacteriuria in the diagnosis of urinary tract infection and the need for a keen awareness of its presence, particularly in young children, is stressed. The approach to the diagnosis, investigation, management and follow-up of children with urinary tract infection is described.     

Urinary tract infection in childhood

Over the past year, research about urinary tract infections in childhood has yielded new data about methods to detect, treat, and evaluate children who develop urinary tract infection. New imaging modalities have been studied. Long term studies following children with urinary tract infection have also been published over the last year. However, major questions remain to be answered, including the underlying basis of host-pathogen interactions in the urinary tract, as well as the most effective methods for clinical diagnosis and management.