UTI: diagnosis and evaluation in symptomatic pediatric patients

Comparative analysis of different loop types for urine culture collection: Implications for quantitative bacterial growth and culture results

We hypothesized that the loop material and size could affect the results of the culture when compared to the calibrated pipette. A total of 484 urine samples were included in the study, and each sample was plated by using different loop types and the calibrated pipette. The bacterial counts per milliliter were calculated and compared, with a focus on the important cutoff values of 10³ and 10⁴ CFU/ml for further identification. When considering the 10³ CFU/ml as cutoff value, 1 µl and 10 µl plastic loops gave the highest sensitivity (86.8 %), whereas the 10 µl metal loop had the lowest sensitivity (64.2 %). For the 10⁴ CFU/ml cutoff value, 1 µl plastic loop inoculation demonstrated the highest sensitivity (75.9 %), while the 10 µl metal loop provided the lowest sensitivity (26.5 %). These results suggest that the single use plastic loops are functional, sensitive, useful especially for critical sample.

Urinary Imaging Findings in Young Infants With Bacteremic Urinary Tract Infection

OBJECTIVES

To describe renal ultrasound (RUS) and voiding cystourethrogram (VCUG) findings and determine predictors of abnormal imaging in young infants with bacteremic urinary tract infection (UTI).

METHODS

We used retrospective data from a multicenter sample of infants younger than 3 months with bacteremic UTI, defined as the same pathogenic organism in blood and urine. Infants were excluded if they had any major comorbidities, known urologic abnormalities at time of presentation, required intensive unit care, or had no imaging performed. Imaging results as stated in the radiology reports were categorized by a pediatric urologist.

RESULTS

Of the 276 infants, 19 were excluded. Of the remaining 257 infants, 254 underwent a RUS and 224 underwent a VCUG. Fifty-five percent had ≥1 RUS abnormalities. Thirty-four percent had ≥1 VCUG abnormalities, including vesicoureteral reflux (VUR, 27%), duplication (1.3%), and infravesicular abnormality (0.9%). Age <1 month, male sex, and non-Escherichia coli organism predicted an abnormal RUS, but only non-E coli organism predicted an abnormal VCUG. Seventeen of 96 infants (17.7%) with a normal RUS had an abnormal VCUG: 15 with VUR (Grade I-III = 13, Grade IV = 2), 2 with elevated postvoid residual, and 1 with infravesical abnormality.

CONCLUSIONS

Although RUS and VCUG abnormalities were common in this cohort, the frequency and severity were similar to previous studies of infants with UTIs in general. Our findings do not support special consideration of bacteremia in imaging decisions for otherwise well-appearing young infants with UTI.

Primary urinary tract infection in infants: prophylaxis for uncomplicated pyelonephritis

BACKGROUND

Urinary tract infection (UTI) is one of the most common causes of unexplained fever in infants with a reported prevalence range of 5-11%. The clinical and laboratory findings were reviewed, and diagnosis and treatment for 95 infants with primary UTI were evaluated in this study.

METHODS

All patients underwent renal ultrasonography, voiding cystourethrogram and 99mTc dimercaptosuccinic acid (DMSA) scan during hospitalization before treatment, with treatment consisting of 2- or 4-week appropriated antibiotic therapy for the patients associated upper UTI, followed by a second DMSA scan 6 months after therapy.

RESULTS

In the present study the main symptom of UTI in infants was fever. High white blood cell count was not necessarily present, and urinalysis was also an imperfect diagnostic tool for discriminating UTI. In addition, colony count from urine culture and kidney ultrasonography was not efficacious in terms of predicting the occurrence of pyelonephritis. Intravenous antibiotic for 1 week followed by 3 weeks of the same oral antibiotic provided good prophylaxis for uncomplicated pyelonephritis.

CONCLUSION

Four weeks of antibiotic treatment resulted in good recovery from pyelonephritis in the present sample of infant primary UTI cases. voiding cystourethrogram, DMSA and ultrasonography scanning should be performed in primary infant UTI.

The role of imaging in urinary tract infections

The aim of imaging in urinary tract infections (UTI) is to detect conditions that must be corrected to avoid imminent deterioration of kidney function, or to prevent recurrent infections and long-term kidney damage. The most threatening conditions are obstruction of an infected upper tract and abscesses of the genitourinary system. An image-guided percutaneous drainage can be lifesaving. The role of imaging in small children with UTI is controversial in terms of the importance of anatomical and functional disorders in relation to the preventive measures to be taken. In newborns identified with hydronephrosis during pregnancy or by neonatal screening, vesicoureteral reflux (VUR) and renal scarring are congenital and not caused by infection. Most of these patients are males and the VUR is of a higher grade than VUR detected in girls after the first UTI. Imaging in children with UTI should only be ordered after a thorough evaluation of the risk of renal damage and the benefits of preventive measures. In adult females, no imaging is necessary in cystitis, while ultrasonography and plain films are recommended in acute pyelonephritis. Since uncomplicated UTI in men is rare, diagnostic imaging should be started early to rule out complicating factors in the urinary tract. In prostatitis, vesiculitis, epididymitis and orchitis the role of imaging is to rule out abscess formation and testicular malignancies.

Risk factors in the development of early technetium-99m dimercaptosuccinic acid renal scintigraphy lesions during first urinary tract infection in children

AIM

To establish the variables that correlate with uptake defects in dimercaptosuccinic acid (DMSA) scintigraphy performed in the acute phase of a first episode of urinary tract infection (UTI).

METHODS

A prospective observational study was conducted in a cohort of 158 consecutive children with a first episode of symptomatic UTI. The therapeutic delay time (TDT) was recorded. DMSA scintigraphy was performed in all children and voiding cystourethrography in 150 of them.

RESULTS

85% of the patients were younger than 2 y. Mean TDT was 33.5 h. The aetiological agent was Escherichia coli in 140 children. DMSA scintigraphy was normal in 81. Vesicoureteric reflux was detected in 33. After a multivariate logistic regression analysis the following variables were retained in the final model: TDT > or = 48 h, growth of bacteria other than E. coli, percentage of polymorphonuclear cells > or = 60% and C-reactive protein > or = 30 mg l(-1).

CONCLUSION

TDT > or = 48 h, bacteria other than E. coli, percentage of polymorphonuclear cells > or = 60% and CRP > or = 30 mg l(-1) influence the findings detected in the DMSA scintigraphy performed in the acute phase of a first episode of UTI.

Diagnosis and imaging in urinary tract infections

The aim of imaging in urinary tract infection is to detect conditions that must be treated in order to avoid immediate deterioration or recurrences, and probable long-term kidney damage. In newborns identified with hydronephrosis during pregnancy or by neonatal screening, vesicoureteral reflux and renal scarring are congenital and not caused by infection. Most of these patients are male and the vesicoureteral reflux is of a higher grade than that detected in girls having had urinary tract infection. In children with urinary tract infection, several authors advocate a more selective policy and recommend imaging only in those children who are at risk for developing renal damage. In adult females no imaging is necessary in cystitis, whereas ultrasonography and plain films are recommended in acute pyelonephritis. Because uncomplicated urinary tract infection in men is rare, diagnostic evaluation including imaging should be started early in order to rule out complicating factors within the urinary tract. The role of imaging in prostatitis, vesiculitis, epididymitis and orchitis is primarily to rule out abscess formation, but also to exclude testicular malignancies.