The interaction of urinary tract infection and renal insufficiency

Regulation of renal aquaporin water channels in acute pyelonephritis

Acute pyelonephritis (APN) is most frequently caused by uropathogenic Escherichia coli (UPEC), which ascends from the bladder to the kidneys during a urinary tract infection. Patients with APN have been reported to have reduced renal concentration capacity under challenged conditions, polyuria, and increased aquaporin-2 (AQP2) excretion in the urine. We have recently shown increased AQP2 accumulation in the plasma membrane in cell cultures exposed to E. coli lysates and in the apical plasma membrane of inner medullary collecting ducts in a 5-day APN mouse model. This study aimed to investigate if AQP2 expression in host cells increases UPEC infection efficiency and to identify specific bacterial components that mediate AQP2 plasma membrane insertion. As the transepithelial water permeability in the collecting duct is codetermined by AQP3 and AQP4, we also investigated whether AQP3 and AQP4 localization is altered in the APN mouse model. We show that AQP2 expression does not increase UPEC infection efficiency and that AQP2 was targeted to the plasma membrane in AQP2-expressing cells in response to the two pathogen-associated molecular patterns (PAMPs), lipopolysaccharide and peptidoglycan. In contrast to AQP2, the subcellular localizations of AQP1, AQP3, and AQP4 were unaffected both in lysate-incubated cell cultures and in the APN mouse model. Our finding demonstrated that cellular exposure to lipopolysaccharide and peptidoglycan can trigger the insertion of AQP2 in the plasma membrane revealing a new regulatory pathway for AQP2 plasma membrane translocation, which may potentially be exploited in intervention strategies.NEW & NOTEWORTHY Acute pyelonephritis (APN) is associated with reduced renal concentration capacity and increased aquaporin-2 (AQP2) excretion. Uropathogenic Escherichia coli (UPEC) mediates changes in the subcellular localization of AQP2 and we show that in vitro, these changes could be elicited by two pathogen-associated molecular patterns (PAMPs), namely, lipopolysaccharide and peptidoglycan. UPEC infection was unaltered by AQP2 expression and the other renal AQPs (AQP1, AQP3, and AQP4) were unaltered in APN.

Construction of an alignment diagram model for predicting calculous obstructive pyonephrosis before PNL

Background

To develop a model for the accurate prediction of calculous obstructive pyonephrosis prior to percutaneous nephrolithotomy (PNL), leading to early local anaesthesia microchannel nephrostomy for drainage of pyonephrosis.

Methods

By comparing the differences in baseline clinical indicators between the pyonephrosis group and nonpyonephrosis groups, independent risk factors were screened out, and a diagnostic alignment diagram model for predicting calculus obstructive pyonephrosis before PNL was established.

Results

Multivariate regression analysis showed that preoperative blood neutrophil count (Neu), serum creatinine level (Scr), serum albumin level (Alb), urine nitrite (UN), hydronephrosis density (HD) and fever history within one month (HFWOM) were independent risk factors for calculous obstructive pyonephrosis. The AUC value of the receiver operating characteristic (ROC) curve was 0.929. The calibration curves showed that the predictive model was well corrected and that the predictive model had strong consistency. Decision analysis curves showed good clinical efficacy of the model.

Conclusion

The alignment diagram model accurately predicts patients with preoperative calculous obstructive pyonephrosis in the PNL and provides an evidence-based basis for early renal microchannel nephrostomy.

Correlation between catheter colonization of central venous catheters and clinical biochemical indicators: A retrospective analysis of the MIMIC‑IV database

BACKGROUND

Clinical studies have not fully assessed the potential impact of patients' biochemical indicators on the rate of positive for central venous catheter-tip microorganism culture (PCMC).

METHODS

Data were obtained from an online Medical Information Mart for Intensive Care IV database. Patients who were ≥18 years old and had central venous catheter-tip culture results without continuous renal replacement therapy were included in the study. A comparison of patient characteristics and their biochemical indicators was made between negative and positive culture results.

RESULTS

A total of 5,323 patients were included in the analysis, including 612 positive (PCMC group) and 4,711 negative culture results (negative for central venous catheter tip catheter-tip microorganism culture [NCMC] group). The only influence factor on PCMC in this study was the serum creatinine (Scr) (odds ratio: 1.312, 95% confidence interval: 1.084-1.590, P = .005), according to a binary logistic regression analysis. The cut-off value of Scr was 3.25 mg/dL. The prevalence of PCMC (27.1% vs 9.1%, P < .001) and Staphylococcus aureus (43.0% vs 18.6%, P < .001) for central venous catheter-tip culture results was much higher in patients with Scr ≥ 3.25 mg/dL than those Scr < 3.25 mg/dL.

CONCLUSIONS

We used the large dataset collected from Medical Information Mart for Intensive Care IV to show that patients with Scr ≥ 3.25 mg/dL had an increased risk for PCMC.

mTOR inhibitor reduces nontumour-related death in liver transplantation for hepatocellular carcinoma

Sirolimus is a regularly applied immunosuppressant for patients undergoing liver transplantation (LT) for hepatocellular carcinoma (HCC). Sirolimus not only significantly inhibits HCC recurrence but also protects renal function. However, the improvement effect of sirolimus on nontumour-related death in patients is still unknown. The aim of our study was to investigate the therapeutic effect of sirolimus on nontumour-related deaths. In this study, we retrospectively enrolled 403 LT patients with HCC from January 1, 2015, to December 31, 2018. The median follow-up time was 47.1 months. The patients were divided into the sirolimus group (N = 184) and the sirolimus-free group (N = 219). There were no significant differences between the sirolimus group and the sirolimus-free group in survival (P = 0.054). In transplant patients who exceeded the Milan or Hangzhou criteria, the sirolimus group achieved higher survival than the sirolimus-free group (P = 0.005; P = 0.02). Moreover, multivariate analysis showed that sirolimus strongly reduced the hazard ratio (HR) for nontumour-related death in LT patients who exceeded the Milan (HR: 0.42; 95% CI: 0.18-1; P = 0.05) or Hangzhou criteria (HR: 0.26; 95% CI: 0.08-0.89; P = 0.032). HCC recurrence increased the risk of nontumour-related death. In conclusion, sirolimus-based immunosuppression can significantly reduce nontumour-related death in LT patients who exceed the criteria for transplantation. In addition, this finding will further promote the application of sirolimus after liver transplantation for hepatocellular carcinoma.

Prevalence and Predictive Factors of Urinary Tract Infection in Kidney Transplant Recipients: A 10-Year Study

OBJECTIVES

Urinary tract infections are the main infectious complications among kidney transplant recipients and are considered as a potential risk factor for poor graft outcomes. However, the risk factors of urinary tract infections are controversial. The purpose of our study was to estimate the incidence and predisposing factors of urinary tract infections in patients undergoing kidney transplant in our teaching hospital of Sahloul, Tunisia.

MATERIALS AND METHODS

We retrospectively analyzed the charts of 141 consecutive adult kidney transplants that were performed at the Department of Nephrology, University Hospital of Sahloul, Tunisia, between January 2007 and April 2016.

RESULTS

Of 141 patients, 72 (51.1%) had urinary tract infections after kidney transplant. Mean age was 32.54 ± 12.1 years; 47.6% were male patients, and 52.4% were female patients. The average time between transplant and early urinary tract infections was 11 days (range, 1-30 days). Among our patient group, 87.8% of urinary tract infections occurred within the first 6 months posttransplant. We collected 205 episodes of urinary tract infections: 66.3% were asymptomatic bacteriuria, 10.2% acute cystitis, and 23.4% pyelonephritis. The estimated risk factors for urinary tract infection included only female sex (P < .05); older age (P = .32), longer duration of catheter (P = .34), and high body mass index (P = .46) were not correlated with urinary tract infection.

CONCLUSIONS

Despite preventive measures, urinary tract infections remain an important cause of morbidity among kidney transplant recipients. In fact, more than half of kidney transplant recipients had at least 1 urinary tract infection after surgery. Female sex was statistically associated with higher risk of urinary tract infection.

QSOFA and SOFA scores are valuable tools for predicting postoperative sepsis resulting from ureteroscopic lithotripsy (URSL)

The sequential organ failure assessment (SOFA) and quick sequential organ failure assessment (qSOFA) scores are new tools which are used to assess sepsis based on the Third International Consensus Definitions for Sepsis and Septic Shock Task Force. This study aimed to evaluate the feasibility of using the SOFA and qSOFA to predict post-ureteroscopic lithotripsy (URSL) sepsis. Patients who underwent URSL due to ureteral stone obstruction were retrospectively reviewed using SOFA and qSOFA scores. Patient characteristics including age, gender, comorbidities, American Society of Anesthesiologists Classification, stone burden, stone location, hydronephrosis status, infectious status, preoperative SOFA and qSOFA score were collected. Preoperative factors were analyzed to determine if they were correlated with postoperative sepsis. A total of 830 patients were included in this study, of whom 32 (3.9%) had postoperative sepsis. Multivariate analysis revealed that older age, proximal ureteral stones, severe hydronephrosis, and high preoperative qSOFA or SOFA score were significantly associated with postoperative sepsis. The areas under the curves of a qSOFA score ≥ 1 and SOFA score ≥ 2 for predicting postoperative sepsis were 0.754 and 0.823, respectively. Preoperative qSOFA and SOFA scores are convenient and effective for predicting post-URSL sepsis. Further preventive strategies should be performed in these high-risk patients.

Urine Microscopy Score and Neutrophil Lymphocyte Ratio at Presentation are Good Biomarkers of Acute Kidney Injury in Patients with Upper Urinary Tract Infection when Assessed in Correlation with Virulence Factors of Escherichia coli and Blood Group Secretor Status

Acute kidney injury (AKI) is a leading cause of morbidity in urinary tract infection (UTI). We aimed to identify simple biomarkers and bacterial virulence factors associated with AKI in a setting of upper UTI due to uropathogenic Escherichia coli (UPEC). We designed a cross-sectional study to analyse biomarkers of AKI in upper UTI patients. A total of 2758 patients presenting to a tertiary care center with symptoms of upper UTI were assessed for the presence of diabetes mellitus, AKI, blood group non-secretors, urine microscopy and hemogram. 300 patients with UPEC in bacterial culture were studied for bacterial virulence factors by phenotypic and genotypic methods and the patients were followed up for a minimum period of two weeks. Patients with diabetes mellitus, non-secretors, Urine microscopy (UM) score > 2 and higher (> 3.9) neutrophil-lymphocyte ratio (NLR) at initial presentation, were found to be significantly associated with AKI at presentation and predicted AKI at 7th and 14th day follow up. They were also significantly associated with need and increased duration of hospitalization. There was no association of virulence factors of UPEC with diabetes mellitus, AKI or need for hospitalization. However, virulence factors had a significant association (p<0.001)with non-secretors. UM score and NLR are simple tools to identify AKI at presentation and predict AKI during follow-up and the need for hospitalization. Patients with diabetes mellitus and non-secretors are also at higher risk of AKI. Non-secretors are significantly associated with both phenotypic and genotypic expression of virulence factors of UPEC.

Risk factors of first and recurrent genitourinary tract infection in patients with type 2 diabetes treated with SGLT2 inhibitors: A retrospective cohort study

AIMS

This retrospective study investigated the risk factors of sodium-glucose cotransporter 2 inhibitors (SGLT2i) -related genitourinary tract infection (GUTI).

METHODS

We used longitudinal claims data from May 2016 to December 2017 from the Chang Gung Research Database. Diabetic patients who used SGLT2i were included. The baseline characteristics risk factors between patients who had GUTI and no GUTI were analyzed.

RESULTS

There were 428(3.43%) patients with the first occurrence of urinary tract infection (UTI) and 5(0.04%) patients with genital tract infection (GTI). Female patients aged ≥ 65 years with HbA1c ≥ 9%, eGFR < 60 ml/min/1.73 m², urine albumin/creatinine ratio (UACR) level ≥30 mg/g, dyslipidemia, diabetic microvascular complications and mood disorder had a higher risk of having the first occurrence of UTI. There was no significant risk factor of GTI. 117 UTI and 3 GTI patients received SGLT2i rechallenging. The recurrent UTI rate was 28.2% and no recurrent GTI was diagnosed. The risk factors included CHD, eGRF < 45 ml/min/1.73 m², and mood disorder (OR, 95% CI: 4.39, 1.15-16.74; 4.11, 1.51-11.19; 5.93, 1.39-25.34, respectively).

CONCLUSIONS

In diabetic patients who had underlying disease of eGRF < 45 ml/min/1.73 m², CHD, and mood disorder had higher risk of recurrent UTI after rechallenging SGLT2i.

Acute pyelonephritis: Increased plasma membrane targeting of renal aquaporin-2

AIM

Aquaporin-2 (AQP2) shuttling between intracellular vesicles and the apical plasma membrane is pivotal in arginine vasopressin-mediated urine concentration and is dysregulated in multiple diseases associated with water balance disorders. Children and adults with acute pyelonephritis have a urinary concentration defect and studies in children revealed increased AQP2 excretion in the urine. This study aimed to analyse AQP2 trafficking in response to acute pyelonephritis.

METHODS

Immunofluorescence analysis was used to evaluate subcellular localization of AQP2 and AQP2-S256A (mimicking non-phosphorylated AQP2 on serine 256) in cells stimulated with bacterial lysates and of AQP2 and pS256-AQP2 in a mouse model at day 5 of acute pyelonephritis. Western blotting was used to evaluate AQP2 levels and AQP2 phosphorylation on S256 upon incubation with bacterial lysates. Time-lapse imaging was used to measure intracellular cAMP levels in response to incubation with bacterial lysates.

RESULTS

In cell cultures, lysates from both uropathogenic and nonpathogenic bacteria-mediated AQP2 plasma membrane targeting and increased AQP2 phosphorylation on serine 256 (pS256) without increasing cAMP levels. Both bacterial lysates induced plasma membrane targeting of AQP2-S256A. Immunofluorescence analysis of renal sections from mice after 5 days of acute pyelonephritis revealed apical plasma membrane targeting of AQP2 and pS256-AQP2 in inner medullary collecting ducts.

CONCLUSION

Uropathogenic bacteria induce AQP2 plasma membrane targeting in vitro and in vivo. cAMP levels were not elevated by the bacterial lysates and AQP2 plasma membrane targeting could occur without S256 phosphorylation. This may explain increased AQP2 excretion in the urine during acute pyelonephritis.

Ileal conduit versus neobladder: A propensity score-matched analysis of the effect on renal function

OBJECTIVES

To analyze the long-term effects of continent (neobladder) compared with incontinent (ileal conduit) urinary diversion.

METHODS

We carried out a retrospective review of our departmental database. Estimated glomerular filtration rate was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. Neobladder and ileal conduit patients were matched in a 1:2 ratio and a propensity score-matched analysis was carried out. Data were summarized using descriptive analysis. Trend plots were generated using baseline and follow-up creatinine values to compare estimated glomerular filtration rate at 3 months, then annually for 5 years. Variables associated with estimated glomerular filtration rate were assessed using multivariate linear analysis.

RESULTS

Our cohort consisted of 137 patients (neobladder n = 50 and ileal conduit n = 87) with a median follow-up time of 3 years (interquartile range 1-7 years). The ileal conduit group had shorter operative times (352 vs 444 min, P < 0.01), intracorporeal diversions were more common (66% vs 44%, P = 0.01), had prior abdominal surgery (66% vs 38%, P < 0.01) and had radiation (9% vs 0%, P = 0.03). The neobladder group more commonly had recurrent urinary tract infections (22% vs 3%, P < 0.01) and a steeper decrease in estimated glomerular filtration rate in the first year. On multivariate linear analysis, age/year (-0.59), body mass index per kg/m² (-0.52), preoperative estimated glomerular filtration rate per unit (0.51), recurrent urinary tract infections (-14.03) and time versus day 90 (year 1, -7.52; year 2, -9.06; year 3, -10.78) were significantly associated with estimated glomerular filtration rate.

CONCLUSION

Ileal conduits and neobladders showed a similar effect on the estimated glomerular filtration rate up to 5 years after robot-assisted radical cystectomy. Recurrent urinary tract infections were associated with a worse estimated glomerular filtration rate.

Septic arthritis in the end-stage renal disease population

Septic arthritis is important to consider in any patient who presents with joint pain because it is a medical emergency with an 11% fatality rate. Diagnosis and treatment may improve prognosis; however, many patients do not regain full joint function. In patients with end-stage renal disease (ESRD), immune dysfunction due to uremia and chronic vascular access leads to increased risk of infection. We examined the incidence, risk factors and sequelae of septic arthritis in a cohort of hemodialysis patients. The US Renal Data System was queried for diagnoses of septic arthritis and selected sequelae using International Statistical Classification of Diseases and Related Health Problems-9 and Current Procedural Terminology-4 codes in patients who initiated hemodialysis between 2005 and 2010. Multivariable logistic regression was used to determine potential risk factors for septic arthritis and its sequelae. 7009 cases of septic arthritis were identified, an incidence of 514.8 per 100,000 persons per year. Of these patients, 2179 were diagnosed with a documented organism within 30 days prior to or 14 days after the septic arthritis diagnosis, with methicillin-resistant Staphylococcus aureus infections (57.4%) being the most common. Significant risk factors for septic arthritis included history of joint disease, immune compromise (diabetes, HIV, cirrhosis), bacteremia and urinary tract infection. One of the four sequelae examined (joint replacement, amputation, osteomyelitis, Clostridioides difficile infection) occurred in 25% of septic arthritis cases. The high incidence of septic arthritis and the potential for serious sequelae in patients with ESRD suggest that physicians treating individuals with ESRD and joint pain/inflammation should maintain a high clinical suspicion for septic arthritis.

Risk factors for urosepsis in chronic kidney disease patients with urinary tract infections

Occurrence of urosepsis is not uncommon following urinary tract infections (UTI). However, there is a lack of evidence explaining the risk factors predisposing to urosepsis in patients with chronic kidney disease (CKD). This retrospective study was undertaken to evaluate the incidence and possible risk factors for urosepsis among patients hospitalized with UTI in a cohort of CKD patients. Patients were divided into the urosepsis group and the non-urosepsis group. Of 489 hospitalized patients with UTI, 70 (14.3%) acquired urosepsis. Stepwise multivariate logistic regression demonstrated that diabetes, urinary catheter and length of hospital stay (p < 0.001 for all) were significant independent predictive risk factors for urosepsis in CKD patients with UTI in addition to age, glomerular filtration rate, hydronephrosis, acute kidney injury and E. coli infection (p < 0.05 for all). Finally, Klebsiella spp. cases were associated with significantly higher odds for urosepsis than E. coli cases (OR: 3.5, 95% CI: 2.86-7.23, p < 0.001 vs. OR: 1.38, 95% CI: 1.19-3.69, p = 0.038). Diabetes, presence of an indwelling urinary catheter, length of hospitalization, and infection with Klebsiella spp were independent risk factors for urosepsis in CKD patients with UTI.

Pyuria, urinary tract infection and renal outcome in patients with chronic kidney disease stage 3-5

Pyuria is common in chronic kidney disease (CKD), which could be due to either urinary tract infection (UTI) or renal parenchymal inflammation. Only little is known regarding the association of pyuria or UTI with renal outcomes. We investigated 3226 patients with stage 3–5 CKD. Pyuria was defined as ≥ 50 WBC per high-power field (hpf) and was correlated to old age, female, diabetes, hypoalbuminemia, lower eGFR, and higher inflammation status. In Cox regression, patients with more than one episode of pyuria in the first year (11.8%) had increased risks for end-stage renal disease (ESRD) [hazard ratio (95% CI): 1.90 (1.58–2.28); p < 0.001], rapid renal function progression [odds ratio (95% CI): 1.49 (1.13–1.95); p = 0.001], and all-cause mortality [hazard ratio: 1.63 (1.29–2.05); p < 0.001], compared to those without pyuria. In a subgroup analysis, the risk of pyuria for ESRD was modified by CKD stages. We investigated the effects of UTI (urinary symptoms and treated by antibiotics) and pyuria without UTI (urine WBC < 50 to ≥ 10/hpf without any episodes of ≥ 50 WBC/hpf or UTI), while both groups were associated with clinical outcomes. In conclusion, CKD stage 3–5 patients with frequent pyuria or UTI episodes have increased risks of renal outcomes.

Urinary tract infection with Klebsiella pneumoniae in Patients with Chronic Kidney Disease

Study Motivation: After assessing electronic databases of medical scientific literature, we have observed that the interrelation between urinary tract infections (UTIs) and chronic kidney disease (CKD) is poorly studied, especially when UTIs are caused by Klebsiella pneumoniae (K. pneumoniae). Materials and methods: K. pneumoniae was isolated in 14 urine samples from patients with CKD addmited in the Nephrology Department of the County Emergency Clinical Hospital Craiova. The isolated strains were statistically analyzed in the correlation with the different clinical and functional parameters (age, gender, CKD stage, comorbidities, biochemical parameters-serum urea, creatinine, uric acid and blood electrolytes). The degree of K. pneumoniae susceptibility to antibiotics from different pharmacodynamic classes was assessed. Results: UTIs with K. pneumoniae in patients with CKD in the investigated period represented 0.51% from the total admissions in the clinic and 32.60% from cases of UTI. Eleven patients with this type of infection (78.56%) were in stage 4 and 5 CKD, and from them 4 also had diabetes mellitus type 2 (28.57%). We observed an increased level for serum creatinine (100%), blood urea (85.71%), and serum uric acid (45.45%). Two patients died after installation of cardiovascular changes in CKD, at advanced ages and in the presence of urinary infection. Multiple drug resistance occurred in 6 strains of K. pneumoniae correlated with the degree of kidney failure, advanced age, male gender, and diabetes mellitus. Conclusions: UTI with K. pneumoniae in patients with CKD is the second cause of urinary infection which raises problems of unfavorable evolution of CKD and also the recurrence of UTI with multiple drug resistance in CKD, which may lead to pharmacotherapeutical problems.

Risk factors for resistance to ciprofloxacin in community-acquired urinary tract infections due to Escherichia coli in an elderly population

BACKGROUND

Antimicrobial resistance to ciprofloxacin is rising worldwide, especially in bacteria causing urinary tract infections (UTIs). Prudent use of current antibiotic drugs is therefore necessary.

OBJECTIVES

We analysed (modifiable) risk factors for ciprofloxacin-resistant Escherichia coli.

METHODS

Urinary cultures of UTIs caused by E. coli were collected from participants in the Rotterdam Study, a prospective cohort study in an elderly population, and analysed for susceptibility to ciprofloxacin. Multivariate logistic regression was performed to investigate several possible risk factors for resistance.

RESULTS

Ciprofloxacin resistance in 1080 E. coli isolates was 10.2%. Multivariate analysis showed that higher age (OR 1.03; 95% CI 1.00-1.05) and use of two (OR 5.89; 95% CI 3.45-10.03) and three or more (OR 3.38; 95% CI 1.92-5.97) prescriptions of fluoroquinolones were associated with ciprofloxacin resistance, while no association between fluoroquinolone use more than 1 year before culture and ciprofloxacin resistance could be demonstrated. Furthermore, a high intake of pork (OR 3.68; 95% CI 1.36-9.99) and chicken (OR 2.72; 95% CI 1.08-6.85) and concomitant prescription of calcium supplements (OR 2.51; 95% CI 1.20-5.22) and proton pump inhibitors (OR 2.04; 95% CI 1.18-3.51) were associated with ciprofloxacin resistance.

CONCLUSIONS

Ciprofloxacin resistance in community-acquired UTI was associated with a high intake of pork and chicken and with concomitant prescription of calcium supplements and proton pump inhibitors. Modification of antibiotic use in animals as well as temporarily stopping the prescription of concomitant calcium and proton pump inhibitors need further evaluation as strategies to prevent ciprofloxacin resistance.

Risk Factors for Development of Acute Kidney Injury in Patients with Urinary Tract Infection

Acute kidney injury (AKI) is associated with high morbidity and mortality. Urinary tract infection (UTI) may be associated with sepsis or septic shock, and cause sudden deterioration of renal function. This study investigated the clinical characteristics and change of renal function to identify the risk factors for development of AKI in UTI patients. This retrospective study was conducted in a tertiary referral center. From January 2006 to January 2013, a total of 790 UTI patients necessitating hospital admission were included for final analysis. Their demographic and clinical characteristics and comorbidities were collected and compared. Multivariate logistic regression analysis was performed to evaluate the risk factors for AKI in UTI patients. There were 97 (12.3%) patients developing AKI during hospitalization. Multivariate logistic regression analysis showed that patients with older age (OR 1.02, 95% CI 1.00–1.04, P = 0.04), diabetes mellitus (DM) (OR 2.23, 95% CI 1.35–3.68, P = 0002), upper UTI (OR 2.63, 95% CI 1.53–4.56, P = 0001), afebrile during hospitalization (OR 1.71, 95% CI 1.04–2.83, P = 0036) and lower baseline eGFR [baseline eGFR 45–59 mL/min/1.73 m² (OR 2.12, 95% CI 1.12–4.04, P = 0.022), baseline eGFR 30-44 mL/min/1.73 m² (OR 4.44, 95% CI 2.30–8.60 P < 0.001) baseline eGFR < 30 mL/min/1.73 m² (OR 4.72, 95% CI 2.13–10.45, P <0.001), respectively] were associated with increased risk for development of AKI. were associated with increased risk for development of AKI. Physicians should pay attention to UTI patients at risk of AKI (advancing age, DM, upper UTI, afebrile, and impaired baseline renal function).

Long-term renal outcomes of episodic urinary tract infection in diabetic patients

OBJECTIVE

Urinary tract infection (UTI) exists in 9%-20% of female and 3%-11% of male patients with diabetes. Diabetic patients experience increased risk of bacteremia, hospitalization, and mortality; however, few studies report long-term renal outcomes of episodic UTI in diabetic patients with chronic kidney disease (CKD).

RESEARCH DESIGN AND METHODS

We investigated 225 diabetic patients admitted with UTI from 2001 to 2011. Based on the glomerular filtration rate (GFR) on admission, we divided the patients into early- (GFR ≥30 ml/min; n=131) and late-stage (stages 4 and 5, GFR <30 ml/min; n=94) CKD groups. We compared admission risk factors, post-UTI GFR decline and its long term trend between these groups.

RESULTS

Poor glycemic control contributed to admission with UTI in the early- and late-stage CKD patients (glycosylated hemoglobin: (9.7±2.8% versus 8.6±2.6%). Early-stage CKD patients exhibited higher urinary glucose. Besides, acute kidney injury (AKI) occurred on admission in late-stage CKD patients (mean eGFR 14.2 ml/min). However, if the infection was cured, almost all diabetic patients reverted to their GFR trends 6 months later.

CONCLUSIONS

Late-stage CKD diabetic patients with UTI are at increased risk of superimposed AKI. Almost all patients gradually reverted to their GFR trend later after infection was cured. Early recognition of complicating AKI factors and aggressive treatment of symptomatic UTI instead of antibiotic prophylaxis for asymptomatic bacteriuria are suggested.

Effect of pravastatin and fosinopril on recurrent urinary tract infections

OBJECTIVES

Recurrent urinary tract infections (UTIs) are a problem affecting both women and men. Animal experiments and in vitro studies indicate that statins might prevent recurrent UTIs. We assessed the effects of pravastatin on UTI antibiotic prescribing among adults.

METHODS

A post hoc analysis was conducted with data from PREVEND IT, a trial among participants randomized to receive pravastatin, fosinopril or placebo in a 2 × 2 factorial design over 4 years. Trial data were linked to the pharmacy prescription database IADB.nl. The primary outcome was the number of prescriptions with a nitrofuran derivate, a sulphonamide or trimethoprim as a proxy for UTI antibiotic prescribing. Generalized estimating equations were used to estimate the effect on the number of UTI antibiotic prescriptions. Cox regression was used to determine the effect on first and second (recurrent) UTI antibiotic prescriptions.

RESULTS

Of the 864 trial participants, 655 were eligible for analysis. During an average follow-up of 3.8 years, 112 (17%) participants received at least one UTI antibiotic prescription. Intention-to-treat analyses showed that pravastatin was associated with a reduced total number of UTI antibiotic prescriptions (relative risk, 0.43; 95% CI, 0.21-0.88) and occurrence of second UTI antibiotic prescriptions [hazard ratio (HR), 0.25; 95% CI, 0.08-0.77]. No significant effect on occurrence of first UTI antibiotic prescriptions was found (HR, 0.83; 95% CI, 0.57-1.20). Fosinopril was associated with an increased occurrence of first UTI antibiotic prescriptions (HR, 1.82; 95% CI, 1.16-2.88). Combination therapy with fosinopril and pravastatin did not significantly influence the number of UTI antibiotic prescriptions.

CONCLUSIONS

This study suggests that pravastatin can reduce the occurrence of recurrent UTIs. Larger studies among patients with recurrent UTIs are warranted.

Assessment of the requisites of microbiology based infectious disease training under the pressure of consultation needs

Background

Training of infectious disease (ID) specialists is structured on classical clinical microbiology training in Turkey and ID specialists work as clinical microbiologists at the same time. Hence, this study aimed to determine the clinical skills and knowledge required by clinical microbiologists.

Methods

A cross-sectional study was carried out between June 1, 2010 and September 15, 2010 in 32 ID departments in Turkey. Only patients hospitalized and followed up in the ID departments between January-June 2010 who required consultation with other disciplines were included.

Results

A total of 605 patients undergoing 1343 consultations were included, with pulmonology, neurology, cardiology, gastroenterology, nephrology, dermatology, haematology, and endocrinology being the most frequent consultation specialties. The consultation patterns were quite similar and were not affected by either the nature of infections or the critical clinical status of ID patients.

Conclusions

The results of our study show that certain internal medicine subdisciplines such as pulmonology, neurology and dermatology appear to be the principal clinical requisites in the training of ID specialists, rather than internal medicine as a whole.

Fibrinogen alpha chain O-glycopeptides as possible markers of urinary tract infection

Urinary tract infection (UTI) is the most common bacterial infection leading to substantial morbidity and considerable health care expenditures across all ages. Here we present an exploratory UPLC-MS study of human urine in the context of febrile, complicated urinary tract infection aimed to reveal and identify possible markers of a host response on infection. A UPLC-MS based workflow, taking advantage of Ultra High Resolution (UHR) Qq-ToF-MS, and multivariate data handling were applied to a carefully selected group of 39 subjects with culture-confirmed febrile Escherichia coli UTI. Using a combination of unsupervised and supervised multivariate modeling we have pinpointed a number of peptides specific for UTI. An unequivocal structural identification of these peptides, as O-glycosylated fragments of the human fibrinogen alpha 1 chain, required MS2 and MS3 experiments on two different MS platforms: ESI-UHR-Qq-ToF and ESI-ion trap, a blast search and, finally, confirmation was achieved by matching experimental tandem mass spectra with those of custom synthesized candidate-peptides. In conclusion, exploiting non-targeted UPLC-MS based approach for the investigation of UTI related changes in urine, we have identified and structurally characterized unique O-glycopeptides, which are, to our knowledge, the first demonstration of O-glycosylation of human fibrinogen alpha 1-chain.

Capillary electrophoresis-time of flight-mass spectrometry using noncovalently bilayer-coated capillaries for the analysis of amino acids in human urine

A capillary electrophoresis-time of flight-mass spectrometry (CE-TOF-MS) method for the analysis of amino acids in human urine was developed. Capillaries noncovalently coated with a bilayer of Polybrene (PB) and poly(vinyl sulfonate) (PVS) provided a considerable EOF at low pH, thus facilitating the fast separation of amino acids using a BGE of 1 M formic acid (pH 1.8). The PB-PVS coating proved to be very consistent yielding stable CE-MS patterns of amino acids in urine with favorable migration time repeatability (RSDs <2%). The relatively low sample loading capacity of CE was circumvented by an in-capillary preconcentration step based on pH-mediated stacking allowing 100-nL sample injection (i.e. ca. 4% of capillary volume). As a result, LODs for amino acids were down to 20 nM while achieving satisfactory separation efficiencies. Preliminary validation of the method with urine samples showed good linear responses for the amino acids (R(2) >0.99), and RSDs for peak areas were <10%. Special attention was paid to the influence of matrix effects on the quantification of amino acids. The magnitude of ion suppression by the matrix was similar for different urine samples. The CE-TOF-MS method was used for the analysis of urine samples of patients with urinary tract infection (UTI). Concentrations of a subset of amino acids were determined and compared with concentrations in urine of healthy controls. Furthermore, partial least squares-discriminant analysis (PLS-DA) of the CE-TOF-MS dataset in the 50-450 m/z region showed a distinctive grouping of the UTI samples and the control samples. Examination of score and loadings plot revealed a number of compounds, including phenylalanine, to be responsible for grouping of the samples. Thus, the CE-TOF-MS method shows good potential for the screening of body fluids based on the analysis of endogenous low-molecular weight metabolites such as amino acids and related compounds.