Susceptibility to acute pyelonephritis or asymptomatic bacteriuria: Host–pathogen interaction in urinary tract infections

Our knowledge of the molecular mechanisms of urinary tract infection (UTI) pathogenesis has advanced greatly in recent years. In this review, we provide a general background of UTI pathogenesis, followed by an update on the mechanisms of UTI susceptibility, with a particular focus on genetic variation affecting innate immunity. The innate immune response of the host is critically important in the antibacterial defence mechanisms of the urinary tract, and bacterial clearance normally proceeds without sequelae. However, slight dysfunctions in these mechanisms may result in acute disease and tissue destruction. The symptoms of acute pyelonephritis are caused by the innate immune response, and inflammation in the urinary tract decreases renal tubular function and may give rise to renal scarring, especially in paediatric patients. In contrast, in children with asymptomatic bacteriuria (ABU), bacteria persist without causing symptoms or pathology. Pathogenic agents trigger a response determined by their virulence factors, mediating adherence to the urinary tract mucosa, signalling through Toll-like receptors (TLRs) and activating the defence mechanisms. In ABU strains, such virulence factors are mostly not expressed. However, the influence of the host on UTI severity cannot be overestimated, and rapid progress is being made in clarifying host susceptibility mechanisms. For example, genetic alterations that reduce TLR4 function are associated with ABU, while polymorphisms reducing IRF3 or CXCR1 expression are associated with acute pyelonephritis and an increased risk for renal scarring. It should be plausible to "individualize" diagnosis and therapy by combining information on bacterial virulence and the host response.     

Is ileal orthotopic bladder substitution with an afferent tubular segment detrimental to the upper urinary tract in the long term?

PURPOSE: We determine long-term morphological changes of the upper urinary tract following ileal orthotopic bladder substitution with an afferent tubular segment without a flap-valve type antireflux procedure. MATERIALS AND METHODS: A consecutive series of long-term survivors (5 years or greater) following ileal orthotopic bladder substitution underwent regular radiological followup with excretory urography. Preoperative and postoperative renal size, parenchymal thickness, pelvicaliceal dilatation and upper urinary tract obstruction were assessed by 2 radiologists. RESULTS: A total of 76 patients with a median followup of 84 months (range 60 to 155) were evaluable. Four patients (2.6%) underwent unilateral nephroureterectomy during followup. Of the remaining 148 renoureteral units 141 (95%) revealed no significant changes in size or parenchymal thickness during followup. Renal size decreased in 6 (4%) and parenchymal thickness in 7 (5%) renoureteral units, 5 of which already had renal pathologies (dilatation, obstruction or hypoplastic kidney) preoperatively. De novo shrinkage of the parenchyma of a preoperatively normal kidney was observed in 2 (1%) renoureteral units associated with stenosis of the ureteroileal anastomosis. Of the 148 renoureteral units 14 (9%) presented with nonobstructive dilatation and 4 (3%) with complete obstruction. Preoperatively average serum creatinine level +/- SD was 98 +/- 19 micromol./l. and 10 years thereafter it was 83 +/- 27 micromol./l. CONCLUSIONS: These data suggest that unidirectional peristalsis of ureters and the afferent tubular ileal segment sufficiently protect the upper urinary tract following ileal bladder substitution up to a decade provided there are no preoperative renal pathology and no anastomotic stricture postoperatively. Additional antireflux flap-valve type implantation techniques are not required.     

Is adjuvant chemotherapy for bladder cancer safer in patients with an ileal conduit than a neobladder?

OBJECTIVE: To assess the safety of adjuvant chemotherapy in patients with neobladder reconstruction in comparison to ileal conduit, as radical cystectomy and urinary diversion is an effective curative surgical treatment for muscle-invasive and high-risk superficial bladder cancer, and adjuvant chemotherapy is usually considered for patients with clinical stage > T2 and nodal metastasis. PATIENTS AND METHODS: We analysed retrospectively patients who had had a radical cystectomy and urinary diversion between 1992 and 2004. Patients with high-risk disease who had adjuvant chemotherapy were identified and stratified based on the type of urinary diversion (ileal conduit or neobladder). The chemotherapy regimen, complications from the adjuvant chemotherapy and other relevant data were analysed. RESULTS: Overall, 343 patients had radical cystectomy, 40 had adjuvant chemotherapy; 25 had an ileal conduit and 15 had a neobladder. Patient characteristics including age, stage and follow-up were similar. In all, 55% of patients had grade 1 toxicity, 23% grade 2, 18% grade 3, and 13% grade 4. No patients had serious organ toxicity and none died. There were no significant differences in the toxicity among the two groups. CONCLUSIONS: Adjuvant chemotherapy appears to be safe in patients with a neobladder and equally safe in patients with an ileal conduit. Hence neobladder reconstruction should not be denied to patients with bladder cancer who are at high risk of recurrence and who might require adjuvant chemotherapy.     

Which patients with transitional cell carcinoma of the bladder or prostatic urethra are candidates for an orthotopic neobladder?

Bladder replacement has become a standard method of urinary diversion in adults undergoing cystectomy. When faced with a treatment decision, the patient and urologist are most comfortable if information is available on short- and long-term possible outcomes of the proposed intervention and on the magnitude of the expected effect. This article presents and discusses absolute and relative contraindications for orthotopic neobladders that may help optimize the clinical results with these procedures. As our own series has progressed, so has our philosophy regarding patients who are candidates for an orthotopic reconstruction. All men who require radical cystectomy as treatment for bladder cancer are initially thought to be appropriate candidates for orthotopic lower urinary tract reconstruction. Given the criteria presented in this article approximately, 80% of men are considered acceptable candidates for a neobladder. By these criteria, 65% of women are adequate candidates for an orthotopic bladder.     

Platelet parameters in children with upper urinary tract infection: is there a specific response?

Although complete blood count is routinely ordered in most upper urinary tract infections (UTI), and information regarding the patient's platelet indices is made available without added cost, the relationship between platelet count and mean platelet volume (MPV) and specific platelet responses to different infectious agents has not been extensively characterized in UTI. The objectives of this study were to examine platelet counts and platelet indices in children with culture-proven upper UTI to determine if there are organism-specific platelet responses. A retrospective analysis of data from all pediatric urine samples processed at Fatih University Medical School microbiology laboratory was undertaken for a period of two years (January 1, 2005, to December 31, 2006). Of the 200 patients with positive urine cultures, 146 (73%) were infected with gram-negative bacteria and 54 (27%) grew gram-positive bacteria. The platelet count during the episode of upper UTI and the incidence of thrombocytosis was significantly higher with the gram-positive infections than with the gram-negative infections or controls (p < 0.05). A statistically significant higher MPV was detected in the subjects with upper UTI (p < 0.05). Also, our data showed a statistically significant increase in MPV with gram-positive infections compared with the other groups (p < 0.05). In conclusion, based on the importance of the hemostatic component in the pathophysiology of infections, our findings of platelet count and MPV and predictivity of the type of the organism would suggest the usefulness of the routine measurements in children with upper UTI.     

Upper urinary tract stone disease in patients with poor performance status: active stone removal or conservative management?

Background

It remains controversial as to whether active stone removal should be performed in patients with poor performance status because of their short life expectancy and perioperative risks. Our objectives were to evaluate treatment outcomes of active stone removal in patients with poor performance status and to compare life prognosis with those managed conservatively.

Methods

We retrospectively reviewed 74 patients with Eastern Cooperative Oncology Group performance status 3 or 4 treated for upper urinary tract calculi at our four hospitals between January 2009 and March 2016. Patients were classified into either surgical treatment group or conservative management group based on the presence of active stone removal. Stone-free rate and perioperative complications in surgical treatment group were reviewed. In addition, we compared overall survival and stone-specific survival between the two groups. Cox proportional hazards analysis was performed to investigate predictors of overall survival and stone-specific survival.

Results

Fifty-two patients (70.3%) underwent active stone removal (surgical treatment group) by extracorporeal shock wave lithotripsy (n = 6), ureteroscopy (n = 39), percutaneous nephrolithotomy (n = 6) or nephrectomy (n = 1). The overall stone-free rate was 78.8% and perioperative complication was observed in nine patients (17.3%). Conservative treatment was undergone by 22 patients (29.7%) (conservative management group). Two-year overall survival rates in surgical treatment and conservative management groups were 88.0% and 38.4%, respectively (p < 0.01) and two-year stone-specific survival rates in the two groups were 100.0% and 61.3%, respectively (p < 0.01). On multivariate analysis, stone removal was not significant, but was considered a possible favorable predictor for overall survival (p = 0.07). Moreover, stone removal was the only independent predictor of stone-specific survival (p < 0.01).

Conclusions

Active stone removal for patients with poor performance status could be performed safely and effectively. Compared to conservative management, surgical stone treatment achieved longer overall survival and stone-specific survival.

     

Bladder,bowel and bugs—bacteriuria in patients with intestinal urinary diversion

The incorporation of intestinal segments into the urinary tract favors bacterial growth of the skin flora, anaerobic bacteria, and uropathogenic strains. The route of infection is ascending; bacteria enter the urethra or the abdominal stoma, which is followed by colonization of the reconstructed lower urinary tract. Bacteriuria is common in all kind of reconstructions; however, urine from neobladder patients with complete emptying is reported to carry bacteria to a lesser extent. Clean intermittent catheterization and residual urine seem to increase the bacterial burden. Patients with augmentation cystoplasties constitute a distinct subgroup in which the remaining part of the bladder tissue is an important determinant of urinary tract susceptibility to infection. The increased rate of bacteriuria in the reconstructed patients indicates a lack of antibacterial defenses, and the symptom free state of the patients suggests that only a restricted host response is triggered. The role of the specific and inflammatory antibacterial defenses in the reconstructed lower urinary tract remains largely unknown.     

Probability of urinary tract infection in infants with ureteropelvic junction obstruction: is antibacterial prophylaxis really needed?

In infants with ureteropelvic junction obstruction (UPJO), the risk of urinary tract infection (UTI) is unknown, and there is a lack of prospective studies showing definitive evidence regarding the benefits and necessity of antibiotic prophylaxis. The aim of this study was to assess the risk of UTI in infants with UPJO and to determine whether the risk varies according to the degree of hydronephrosis. Infants with hydronephrosis detected prenatally or within the postnatal 28th day and who had no previous history of UTI were followed prospectively without antibacterial prophylaxis. Imaging studies were performed according to our Pediatric Uro-Nephrology Study Group protocol. Dimercaptosuccinate (DMSA) scintigraphy was performed in all infants at the end of 1 year of follow-up. Eighty-four infants (56 boys, 28 girls) were included in the study. The distribution of patients in each hydronephrosis grading group was incidentally similar. Within a median follow-up period of 18 (12–24) months, none of the patients had UTI. Furthermore, no pyelonephritic scar was found on DMSA scans in any patient. We conclude that prophylactic antibiotic usage is not indicated in infants with UPJO, regardless of the severity of hydronephrosis, as the risk of UTI is minimal in this population.     

Is urinary tract infection after urodynamic study predictable?

BackgroundUrodynamic study (UDS) is a widely used diagnostic tool to evaluate lower urinary tract and pelvic floor function and provides objective information about different parameters related to it.AimTo determine the incidence of urinary tract infections (UTI) after UDS and identify the risk factors predisposing to it.Settings and designA prospective study conducted over 7 months between September 2013 and March 2014 at Medway Maritime Hospital, Gillingham, Kent, UK.Materials and methodsOne hundred consecutive patients presenting with lower urinary tract symptoms (LUTSs), overactive bladder (OAB), and stress urinary incontinence (SUI) were investigated with UDS. All patients had urine dipstick testing before UDS and urine cultures 72 hours after the investigation. Data were analyzed using SPSS version 17.0. The χ² test was used to determine statistical significance with p < 0.05 considered significant.ResultsThe median age was 66 years (interquartile range, 37–81 years) and the commonest indication was LUTSs (63%). Fourteen patients (14%) had positive urine cultures postprocedure, however, only 12 patients (12%) were symptomatic and required treatment with antibiotics. The most common organism was Escherichia coli (58%). Male gender (p = 0.02), high residual urine of > 100 mL (p = 0.01), and UDS done for LUTSs (p = 0.001) were associated with UTI after UDS.ConclusionUDS is associated with significant morbidity due to UTI and prophylactic antibiotics may be considered in high risk patients.     

Is a dipstick test sufficient to exclude urinary tract infection in women with overactive bladder?

Introduction and hypothesis  

A dipstick test is recommended to screen for urinary tract infection in patients with overactive bladder (OAB). It was the aim of this study to test if a dipstick test is sufficient to identify patients with urinary tract infection attending a urological private practice because of OAB.     

Follow-up imaging of the urinary tract in spinal injury patients: is a KUB necessary with every ultrasound?

STUDY DESIGN: Prospective study of 100 consecutive patients. OBJECTIVES: To evaluate the diagnostic usefulness of the urinary tract (KUB) radiograph routinely performed as part of spinal injury patient urinary tract screening with ultrasound (US) and the KUB radiograph. SETTING: Orthopaedic and District General Hospital with spinal injuries unit, UK. METHODS: Prospective study of the urinary tract of 100 consecutive routine follow-up spinal injury patients with KUB (kidneys, ureters, bladder) radiograph and US of the urinary tract. The percentage of the visualised area of kidneys and urinary bladder and relevant abnormal findings were recorded. Relevant patient history was recorded. RESULTS: In all, 80 men 20 women were examined (average age 46 years, average time since injury 11 years). A total of 199 kidneys and 99 urinary bladders were examined. On average, less than 50% of the renal area and about 70-75% of the urinary bladder area were visualised. Five patients had renal stones identified on the KUB radiograph, and of these two were seen on US. There were no stones seen on US only. The patient history was not helpful to identify patients with renal stones. Significant further renal abnormalities were identified with US in 14 patients, and with the KUB radiograph in 0 patients. Significant urinary bladder abnormalities were identified with US in 20 patients, and with the KUB radiograph in 0 patients. CONCLUSION: On average, less than 50% of the kidney area is visualised on the KUB due to overlying bowel markings making the KUB radiograph a poor tool to assess the kidneys. The KUB radiograph and US are poor tools to assess urinary tract stones. In the absence of a therapeutic consequence, the KUB radiograph does not seem justified in the routine follow-up of the urinary tract in spinal injury patients.     

Assessment of long-term quality of life in patients with orthotopic neobladder followed for more than 5 years

Introduction  

We analyzed the general health QOL (GH-GOL), urinary QOL, and sexual QOL in patients with orthotopic neobladder who were followed for more than 5 years.