Procalcitonin, C-reactive protein, and erythrocyte sedimentation rate for the diagnosis of acute pyelonephritis in children

Biomarkers for urinary tract infection: present and future perspectives

A prompt diagnosis of urinary tract infection (UTI) is necessary to minimize its symptoms and limit sequelae. The current UTI screening by urine test strip analysis and microscopic examination has suboptimal diagnostic accuracy. A definitive diagnosis of UTI by urine culture takes two to three days for the results. These limitations necessitate a need for better biomarkers for the diagnosis and subsequent management of UTI in children. Here, we review the value of currently available UTI biomarkers and highlight the potential of emerging biomarkers that can facilitate a more rapid and accurate UTI diagnosis. Of the newer UTI biomarkers, the most promising are blood procalcitonin (PCT) and urinary neutrophil gelatinase-associated lipocalin (NGAL). PCT can provide diagnostic benefits and should be considered in patients who have a blood test for other reasons. NGAL, which is on the threshold of clinical care, needs more research to address its scope and utilization, including point-of-care application. Employment of these and other biomarkers may ultimately improve UTI diagnosis, guide UTI therapy, reduce antibiotic use, and mitigate UTI complications.

Role of N-acetylkynurenine in mediating the effect of gut microbiota on urinary tract infection: a Mendelian randomization study

Introduction

This study explored the causal connections between gut microbiota (GM), urinary tract infection (UTI), and potential metabolite mediators using Mendelian randomization (MR).

Methods

We utilized summary statistics from the most comprehensive and extensive genome-wide association studies (GWAS) available to date, including 196 bacterial traits for GM, 1,091 blood metabolites, 309 metabolite ratios, alongside UTI data from ukb-b-8814 and ebi-a-GCST90013890. Bidirectional MR analyses were conducted to investigate the causal links between GM and UTI. Subsequently, two MR analyses were performed to identify the potential mediating metabolites, followed by a two-step MR analysis to quantify the mediation proportion.

Results

Our findings revealed that out of the total 15 bacterial traits, significant associations with UTI risk were observed across both datasets. Particularly, taxon g_Ruminococcaceae UCG010 displayed a causal link with a diminished UTI risk in both datasets (ukb-b-8814: odds ratio [OR] = 0.9964, 95% confidence interval [CI] = 0.9930-0.9997, P = 0.036; GCST90013890: OR = 0.8252, 95% CI = 0.7217-0.9436, P = 0.005). However, no substantial changes in g_Ruminococcaceae UCG010 due to UTI were noted (ukb-b-8814: β = 0.51, P = 0.87; ebi-a-GCST90013890: β = -0.02, P = 0.77). Additionally, variations in 56 specific metabolites were induced by g_Ruminococcaceae UCG010, with N-acetylkynurenine (NAK) exhibiting a causal correlation with UTI. A negative association was found between g_Ruminococcaceae UCG010 and NAK (OR: 0.8128, 95% CI: 0.6647-0.9941, P = 0.044), while NAK was positively associated with UTI risk (OR: 1.0009; 95% CI: 1.0002-1.0016; P = 0.0173). Mediation analysis revealed that the association between g_Ruminococcaceae UCG010 and UTI was mediated by NAK with a mediation proportion of 5.07%.

Discussion

This MR study provides compelling evidence supporting the existence of causal relationships between specific GM taxa and UTI, along with potential mediating metabolites.

Evaluation of new generation systemic immune-inflammation markers to predict urine culture growth in urinary tract infection in children

Objective

Systemic inflammation has been implicated in the development and progression of urinary tract infection (UTI). Accordingly, the aim of this study is to determine whether the white blood cell (WBC), C-reactive protein (CRP), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII) are useful markers to predict of urine culture growth in children with UTI. The second aim of this study is to evaluate the prevalence of UTI pathogens, antibiotic resistance patterns, and empirical treatment options in children diagnosed with UTI based on laboratory and clinical findings.

Method

The study population comprised 413 cases (positive urine culture) and 318 cases (negative urine culture) of pediatric patients with UTI.

Results

There was no statistically significant difference observed in the median levels of hemoglobin, hematocrit, and platelet between the negative and positive culture groups. The median levels of monocytes, WBC, NLR, SII, and CRP of the patients with a positive urine culture were shown to be statistically significantly higher than the patients with a negative urine culture. The AUC value was 0.747 (0.710-0.784) for CRP with a cutoff value of 3.2, the sensitivity value was 56.4%, and the specificity value was 98.4% in terms of UTI. The AUC value was 0.733 (0.697-0.769) for SII with a cutoff value of 600, the sensitivity value was 58.4%, and the specificity value was 83.0%. The AUC value was 0.732 (0.697-0.769) for NLR with a cutoff value of 2, the sensitivity value was 57.4%, and the specificity value was 81.1%.

Conclusion

WBC, CRP, NLR, PLR, and SII could potentially serve as useful independent diagnostic or complementary markers for disease in children diagnosed with UTI who exhibit a positive urine culture. Escherichia coli was found to be the most common causative agent, and the commonly prescribed antibiotic was cephalosporin. However, it was observed that all identified agents of pediatric UTIs in our center exhibited high resistance to cefuroxime, trimethoprim-sulfamethoxazole, cefixime, ampicillin, and ceftriaxone.

C‐reactive protein, procalcitonin, and erythrocyte sedimentation rate for the diagnosis of lower urinary tract infection in older people

This is a protocol for a Cochrane Review (diagnostic). The objectives are as follows:

The Diagnostic Accuracy Of Procalcitonin for Urinary Tract Infection in Hospitalized Older Adults: a Prospective Study

BACKGROUND

The diagnosis of urinary tract infection (UTI) is challenging among hospitalized older adults, particularly among those with altered mental status.

OBJECTIVE

To determine the diagnostic accuracy of procalcitonin (PCT) for UTI in hospitalized older adults.

DESIGN

We performed a prospective cohort study of older adults (≥65 years old) admitted to a single hospital with evidence of pyuria on urinalysis. PCT was tested on initial blood samples. The reference standard was a clinical definition that included the presence of a positive urine culture and any symptom or sign of infection referable to the genitourinary tract. We also surveyed the treating physicians for their clinical judgment and performed expert adjudication of cases for the determination of UTI.

PARTICIPANTS

Two hundred twenty-nine study participants at a major academic medical center.

MAIN MEASURES

We calculated the area under the receiver operating characteristic curve (AUC) of PCT for the diagnosis of UTI.

KEY RESULTS

In this study cohort, 61 (27%) participants met clinical criteria for UTI. The median age of the overall cohort was 82.6 (IQR 74.9-89.7) years. The AUC of PCT for the diagnosis of UTI was 0.56 (95% CI, 0.46-0.65). A series of sensitivity analyses on UTI definition, which included using a decreased threshold for bacteriuria, the treating physicians' clinical judgment, and independent infectious disease specialist adjudication, confirmed the negative result.

CONCLUSIONS

Our findings demonstrate that PCT has limited value in the diagnosis of UTI among hospitalized older adults. Clinicians should be cautious using PCT for the diagnosis of UTI in hospitalized older adults.

Predictors of ultrasound abnormalities among women treated for community-onset acute pyelonephritis: a prospective study

OBJECTIVES

Acute pyelonephritis (AP) is a common but potentially severe infection. It may be complicated by pyelocaliceal dilatation which requires emergency urine drainage. In outpatient care, ultrasound (US) appears to be the easier way to diagnose pyelocaliceal dilatation, though most APs will not be complicated and do not require immediate ultrasound. We aimed to identify predictors of ultrasound abnormalities in an outpatient AP cohort.

METHODS

A prospective study was conducted from April 2006 to September 2019 in an outpatient care network. Patients aged 15 and over treated for AP were included. Men, pregnant women, patients with solitary kidney, and patients without data on their management were excluded. A common algorithm ensured the same approach from diagnosis to treatment. Data were collected prospectively in an anonymized database. We described the characteristics of the patients. Univariate and then multivariate analyses were performed to identify predictors of ultrasound abnormalities.

RESULTS

2054 women were treated for AP. Among them, 32.5% (n = 667) had a history of urinary tract infections and 5.8% (n = 120) of uropathy. The most frequent uropathogen was E. coli (n = 1,432; 69.7%); Extended-Spectrum Beta-Lactamases (ESBLs) were found in 39 (1.9%) urine cultures. Ultrasound was abnormal in 7.3% (n = 149). Age over 55 years (OR = 2.23; 95% CI 1.58‒3.15; p < 0.0001) and uropathy (OR = 3.69; 95% CI 2.26‒6.01; p < 0.0001) were independently identified as predictors of ultrasound abnormalities. The risk increased by 1.8% (95% CI 1.0‒2.6) with each additional year of age.

CONCLUSIONS

This study identified age and uropathy as independent predictors of abnormal ultrasound in women treated with community-onset AP.

The Influence of Non-E. Coli or Extended-Spectrum β-Lactamase-Producing Bacterial Growth on the Follow-Up Procedure of Infants with the First Febrile Urinary Tract Infection

OBJECTIVE

To evaluate the effects of non-E. coli or extended-spectrum β-lactamase-positive (ESBL-positive) microorganism growth in the first febrile urinary tract infection (UTI) of infants on laboratory findings or renal parenchymal damage presenting the severity of inflammation, anatomic abnormalities defined by imaging studies, and recurrent UTIs in the follow-up period.

METHODS

The data of patients aged between 2 and 24 mo and followed up for at least 6 mo with febrile UTI guideline of the authors' pediatric-nephrology clinic, were retrospectively analyzed. Ultrasonography was performed in all the cases at the time of UTI and dimercaptosuccinic-acid (DMSA) at least 4 mo after the infection. Voiding cystourethrography (VCUG) was performed only if ultrasonography findings were abnormal, the uptake deformity was detected in DMSA scan, or the patients experienced recurrent UTIs. The patients were grouped concerning E. coli or non-E. coli and ESBL-PB or non-ESBL-BP growth in the urine cultures.

RESULTS

There were 277 infants followed up for 28.55 ± 15.24 (6-86) mo. The causative microorganisms were non-E. coli in 73 (26.4%) and ESBL-PB in 58 (20.9%) cases. CRP values, pyuria, and leukocyte-esterase positivity were significantly higher in UTIs caused by E. coli compared to non-E. coli bacteria. All clinical and laboratory findings were similar between the ESBL-PB and non-ESBL groups, but abnormal ultrasonography findings were more common in non-E. coli group.

CONCLUSION

E. coli causes more severe inflammation, but non-E. coli infections are more frequently associated with ultrasound abnormalities. However, ESBL production did not affect either laboratory or radiological findings in the present cohort.

Serum procalcitonin to differentiate acute antepartum pyelonephritis from asymptomatic bacteriuria and acute cystitis during pregnancy: A multicenter prospective observational study

OBJECTIVE

To examine whether serum procalcitonin (PCT) is useful for differentiating acute pyelonephritis (APN) from asymptomatic bacteriuria and acute cystitis during pregnancy.

METHODS

A multicenter prospective observational study was conducted to compare serum white blood cell (WBC) counts, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, and PCT level among pregnant women with asymptomatic bacteriuria, acute cystitis, and APN and healthy pregnant women (controls). Utility of WBC count, ESR, CRP, and PCT biomarkers for the prediction of APN during pregnancy were measured.

RESULTS

Area under the curve (AUC) values of PCT, CRP, ESR, and WBC count for predicting asymptomatic bacteriuria were 0.576, 0.628, 0.542, and 0.532, respectively; those for predicting acute cystitis were 0.766, 0.735, 0.681, and 0.597, respectively; and those for predicting acute pyelonephritis 0.859, 0.763, 0.711, and 0.732, respectively. Compared with the other inflammatory markers used to predict APN, PCT exhibited the highest AUC (0.859 [95% confidence interval (CI) 0.711-0.935]). A cutoff value of >0.25 ng/ml had a sensitivity of 87% and a specificity of 79%.

CONCLUSION

Serum PCT can be a valuable addition to existing methods of differentiating asymptomatic bacteriuria, acute cystitis, and APN during pregnancy and can facilitate the early identification of APN during pregnancy.

Diffusion-Weighted MRI in the Evaluation of Renal Parenchymal Involvement during Febrile Urinary Tract Infections in Children: Preliminary Data

Background: Urinary tract infection (UTI) is the most common infection in pediatric-age patients. Acute pyelonephritis (PNA) represents a worrying situation in pediatric patients due to the risk of sepsis and long-term cicatricial consequences. The purpose of this retrospective study is to evaluate the diagnostic role of DW-MRI in relation to clinical data, to understand if there are any clinical parameters useful in identifying which patients should undergo it. Methods: According to inclusion and exclusion criteria, we enrolled 51 patients ≤15 years old admitted to our Institute between September 2012 and April 2020 with a febrile UTI who underwent DW-MRI evaluation. Clinical, laboratory and imaging data were collected. Statistical analysis was performed. Results: 34 of 51 patients with an fUTI (66.7%) showed signs of acute parenchymal involvement at DW-MRI evaluation. In 27 of these 34 (79.4%), DW-MRI showed multiple areas of pyelonephritis. A statistically significant relationship (p = 0.0004) between older age at admission and pyelonephritis was demonstrated. No statistically significant relationship was found between the other clinical, anamnestic and laboratory parameters and the outcome of DWI. Only two ultrasound examinations allowed the identification of pathological areas on the renal parenchyma. Conclusions: From these preliminary investigations, we can say that selecting the patients with fUTI on whom to perform a DW-MRI is difficult. Nevertheless, thanks to the low cost, the very rare need for sedation and the accuracy in identifying pyelonephritic areas, the use of DW-MRI in patients with febrile UTI seems recommendable.

Diffusion-Weighted MRI in the Evaluation of Renal Parenchymal Involvement during Febrile Urinary Tract Infections in Children: Preliminary Data

Background: Urinary tract infection (UTI) is the most common infection in pediatric-age patients. Acute pyelonephritis (PNA) represents a worrying situation in pediatric patients due to the risk of sepsis and long-term cicatricial consequences. The purpose of this retrospective study is to evaluate the diagnostic role of DW-MRI in relation to clinical data, to understand if there are any clinical parameters useful in identifying which patients should undergo it. Methods: According to inclusion and exclusion criteria, we enrolled 51 patients ≤15 years old admitted to our Institute between September 2012 and April 2020 with a febrile UTI who underwent DW-MRI evaluation. Clinical, laboratory and imaging data were collected. Statistical analysis was performed. Results: 34 of 51 patients with an fUTI (66.7%) showed signs of acute parenchymal involvement at DW-MRI evaluation. In 27 of these 34 (79.4%), DW-MRI showed multiple areas of pyelonephritis. A statistically significant relationship (p = 0.0004) between older age at admission and pyelonephritis was demonstrated. No statistically significant relationship was found between the other clinical, anamnestic and laboratory parameters and the outcome of DWI. Only two ultrasound examinations allowed the identification of pathological areas on the renal parenchyma. Conclusions: From these preliminary investigations, we can say that selecting the patients with fUTI on whom to perform a DW-MRI is difficult. Nevertheless, thanks to the low cost, the very rare need for sedation and the accuracy in identifying pyelonephritic areas, the use of DW-MRI in patients with febrile UTI seems recommendable.