• Childhood Kidney Diseases
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• v.13 no.1
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• pp.49-55
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• 2009

Purpose : We aimed to compare the frequency of positive repeat urine cultures 48 hours after antimicrobial treatment between anatomically normal and abnormal urinary tract Infection (UTI) groups to determine the potential clinical usefulness of the tests. Methods : We reviewed medical records of 930 patients under age 14, who had been admitted for UTI at Gyeongsang National University Hospital from January 1, 1998 to August 1, 2008. The eligible patients were divided into two groups the anatomically normal UTI group and the anatomically abnormal UTI group. Statistical analyses were performed with variables consisting of the sex ratio, age distribution and the frequency of positive repeat urine cultures of each group. Results : The sex ratio of the anatomically normal UTI group was M:F=1.9:1, whereas that of the anatomically abnormal UTI group was M:F=3.5:1 (P=0.019). For age distribution, it was found that the mean age of the anatomically normal UTI group was $0.82{\pm}1.83$ years, whereas that of the anatomically abnormal UTI group was $1.18{\pm}2.57$ years (P=0.113). The frequency of positive repeat urine cultures in the anatomically normal UTI group was 3/279 (1.1%), whereas that of the anatomically abnormal UTI group was 1/90 (1.1%) (P=0.675). Conclusion : We conclude that performing a repeat urine culture is not justified in terms of clinical usefulness, and it is unreasonable to use the results as an index of therapeutic success. A follow-up urine culture is unnecessary in patients with both the anatomically normal and abnormal UTI group.

• Clinical and Experimental Pediatrics
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• v.52 no.8
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• pp.917-921
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• 2009

Purpose : Although renal ultrasonography (USG) has improved the detection rate of hydronephrosis (HN), its clinical courses and postnatal management remains controversial. Here, we reviewed the clinical features of patients with HN according to the grades. Methods : We retrospectively studied 207 patients who were regularly followed-up among 367 patients with HN detected by renal USG postnatally between April 1998 and December 2007. These patients were grouped into four groups, grades 1-4, according to renal pelvic diameter (RPD). For analysis, each group was merged into two categories (mild: grade 1, 2; severe: grade 3, 4). Results : During follow-up, 128 episodes of urinary tract infection (UTI) occurred in 91 patients. According to grades from 1 to 4, 35/89 (39.3%), 41/88 (46.5%), 11/22 (50%), and 4/8 (50%), respectively, had UTI, without any significance between the mild and severe groups. However, the severe group presented a higher risk in cumulative episodes of UTI per year (P=0.041). The spontaneous resolution of HN was observed in 103 (58.8%) of the 175 mild group patients and in 3 (10.7%) of the 28 severe group patients (P<0.001). Furthermore, the detection rate of prenatal HN by prenatal USG was much higher in patients with severe RPD (P<0.001). Conclusion : We found that the severer the grade of HN, the lower was the rate of spontaneous resolution and higher was the frequency of UTI. Therefore, the establishment of guidelines for managing treatments such as antibiotic prophylaxis for patients with HN is needed to improve renal prognosis.

• Childhood Kidney Diseases
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• v.15 no.1
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• pp.66-75
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• 2011

Purpose: Early diagnosis and treatment of febrile urinary tract infection (UTI) in children is important to prevent kidney damage. This study aims to evaluate the relationship between the presence of pyuria, the severity, and underlying genitourinary anomalies in patients with UTI. Methods: We retrospectively reviewed 293 patients with febrile UTI who were admitted to Korea University Guro Hospital during the period from June, 2007 until January, 2010. We divided the patients into two groups, one with the finding of pyuria at admission, and the other without, and compared the fever duration, white blood cell counts (WBC) and C-reactive protein (CRP) in peripheral bloods, hydronephrosis, cortical defects, vesicoureteral reflux and admission period. Results: Among the 293 patients with febrile UTI, 189 patients showed findings of pyuria whereas 104 patients did not. Patients with pyuria showed an increment of WBC ($14,694{\pm}485.2$ vs. $11,374{\pm}451.2/uL$, P <0.05) and CRP ($46.9{\pm}3.9$ vs $17.1{\pm}3.6$ mg/L, P <0.05) in peripheral blood sample. The presence of cortical defects (21.7 Vs 5.8%, P <0.05) and vesicoureteral reflux (15.9 Vs 6.7%, P <0.05) was also increased in patients with pyuria compared to patients without pyuria. There were no specific differences in fever duration, admission period, and hydronephrosis. Within the group with pyuria, CRP in peripheral blood sample increased proportionally with the increment of pyuria (P <0.05). Conclusion: In patients with febrile UTI, the increment of WBC in the urine sample can be a helpful predictor for increased CRP in peripheral blood and acute pyelonephritis.

• Childhood Kidney Diseases
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• v.15 no.1
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• pp.58-65
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• 2011

Purpose: Some hormonal and electrolyte abnormalities have been reported in pediatric patients with urinary tract infection (UTI). This study aimed to investigate the relationships between the imbalance of electrolytes and the severity of infection and associated urologic anomalies in children with febrile UTI. Methods: We retrospectively reviewed 267 patients with febrile UTI who were admitted to Korea University Guro Hospital during the period from January, 2007 until February, 2010. According to the presence of hyponatremia or hyperkalemia, clinical parameters and associated renal anomalies, such as hydronephrosis, cortical defects and vesicoureteral reflux, were compared. Results: 42.7% of all patients had decreased concentration of serum sodium. In patients with decreased concentration of serum sodium, cortical defects were significantly increased compared to normal patients (40.4% vs. 14.4%, P <0.05). White blood cell (WBC) counts ($15,721{\pm}6,553/uL$ vs. $12,885{\pm}5,367/uL$, P <0.05), C-reactive protein (CRP) ($61.8{\pm}56.1$ mg/L, vs. $29.9{\pm}39.8$ mg/L, P <0.05), and erythrocyte sedimentation rate (ESR) ($43.9{\pm}34.3$ mm/hr vs. $27.4{\pm}26.8$ mm/hr, P <0.05) in peripheral blood showed significant increases in the group with decreased concentration of serum sodium. Duration of fever, presence of gastrointestinal symptom, the incidence of hydronephrosis and vesicoureteral reflux did not differ between the two groups. None of the patients had significant hyperkalemia. Conclusion : We suggest that decreased concentration of serum sodium in febrile UTI might be a helpful marker for leukocytosis and increased CRP and ESR in peripheral blood, and acute pyelonephritis.

• Clinical and Experimental Pediatrics
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• v.48 no.7
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• pp.760-765
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• 2005

Purpose : We studied the changes in antibiotic sensitivity to the causative organisms of urinary tract infection(UTI), in order to provide useful information on the choice of adequate drugs in the treatment of UTI. Methods : We retrospectively analyzed the major causative organisms and their antibiotic sensitivities in 69 patients diagnosed with UTI in the Department of Pediatrics, Samsung Cheil Hospital from 2002 to 2003. Results : The frequency of UTI was the highest in infants younger than 1 year of age(88.4 percent). The male to female ratio was 3.05 : 1. Escherichia coli was the most frequent organism(78.3 percent), followed by Klebsiella(11.6 percent), Pseudomonas(2.9 percent), Proteus(2.9 percent), Enterobacter, Morganelle, and Enterococcus(1.4 percent) in descending order. Antibiotic sensitivity of gram negative organisms was above 90 percent against imipenem, amikacin, 80 percent against aztreonam, cefepime, ceftriaxone, 50-70 percent against gentamicin, trimethoprime-sulfamethoxazole (TMP/SMX), and 23 percent against ampicillin(23.4 percent). Conclusion : Antibiotict sensitivity of gram negative organisms was high to amikacin and third generation cephalosporins but low to ampicillin, gentamicin and TMP/SMX. The use of ampicillin or TMP/SMX, as the first choice of the empiric and prophylactic treatment for UTI, should be reconsidered and investigated further.

• Clinical and Experimental Pediatrics
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• v.49 no.1
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• pp.87-92
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• 2006

Purpose : It is difficult to make a distinction between lower urinary tract infection(UTI) and acute pyelonephritis(APN) during the acute phase of febrile UTI due to nonspecific clinical symptoms and laboratory findings, especially among young children. We measured the serum procalcitonin(PCT) in children with UTI to distinguish between acute pyelonephritis and lower UTI, and to determine the accuracy of PCT measurement compared with other inflammatory markers. Methods : Serum samples were taken from children who admitted with unexplained fever or were suspected of having UTI. 51 children(mean $12.2{\pm}11.4$ months) were enrolled in this study. Leukocyte counts, erythrocyte sedimentation rates(ESR) and C-reactive protein(CRP) were also measured. Renal parenchymal involvement was assessed by $^{99m}Tc$ DMSA scintigraphy in the first 7 days after admission. PCT was measured by immunoluminometric assay. Results : PCT values were significantly correlated with the presence of renal defects in children with UTI(n=16)($5.06{\pm}12.97{\mu}g/L$, P<0.05). However, PCT values were not significantly different between children with UTI without renal damage(n=18) and children without UTI(n=17). Using a cutoff of $0.5{\mu}g/L$ for PCT and 20 mm/hr for ESR, 20 mg/L for CRP, sensitivity and specificity in distinguishing between UTI with and without renal involvement were 81.3 percent and 88.9 percent for PCT 87.5 percent and 72.2 percent for ESR, and 87.5 percent and 55.6 percent for CRP, respectively. Positive and negative predictive values were 86.7 percent and 84.2 percent for PCT and 60.9 percent and 81.8 percent for CRP, respectively. Conclusion : In febrile UTI, PCT values were more specific than CRP, ESR and leukocyte count for the identification of patients who might develop renal defects.

• Clinical and Experimental Pediatrics
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• v.46 no.3
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• pp.265-270
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• 2003

Purpose : To characterize the infants under 3 months of age with urinary tract infections(UTIs), and especially patients with bacteremia or meningitis Methods : Hospital records of all the infants under 3 months of age discharged from our hospital for 69 consecutive months with the diagnosis of initial episode of UTI were reviewed. UTI was defined when patients had fever with pyuria, and had urine culture results of ${\geq}10^5$ colony forming units/mL from a bag specimen. Patients with previously known urologic abnormality or immunodeficiency were excluded. Nosocomial infections were also excluded from the study. Results : The male:female ratio was 35 : 6. Of the urine cultures, 40(97.6%) yielded single pathogen, one yielded two pathogens. Escherichia coli was the predominant isolate from the urine. Five patients(12%) also had bacteremia. Pathogens isolated from the blood cultures were E. coli(4) and Enterococcus faecalis(1). No patient had culture-positive meningitis or cerebrospinal fluid pleocytosis. Clinical or laboratory findings between patients with and without bacteremia were not different significantly. The rate of vesicoureteral reflux(VUR) was 44%. The sensitivity of ultrasound for detection of VUR was 38%; specificity was 50%. Conclusion : Clinical and laboratory data were not helpful for identifying patients with bacteremia at the time of presentation. Consequently, blood cultures need to be obtained from all febrile infants under 3 months of age with UTIs. A large-scale study including the indication of lumbar puncture for infants with a febrile UTI and study of evaluation and treatment of infants under 3 months of age with UTIs are required.

• Clinical and Experimental Pediatrics
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• v.52 no.10
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• pp.1147-1152
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• 2009

Purpose:To characterize the pathogens and their antibiotic susceptibilities in more than 24-month-old children with urinary tract infection (UTI) and to study the Escherichia coli antimicrobial susceptibility trend. Methods:We retrospectively reviewed the record of more than 24-month-old children with UTI between January 2003 and December 2008. Positive results for 1 bacterial species with a colony count of ${\geq}10^5CFU/mL$ was considered statistically significant. We analyzed uropathogens and their antibiotic susceptibilities. To investigate E. coli antibiotic susceptibility trend, we compared 2 study periods (group A: 2003-2005 versus group B: 2006-2008) using the chi-square test for trend. Results:In all, 63 bacterial isolates were identified in children with febrile UTI. The most common pathogen was E. coli (77.8%). There was no difference in the resistance patterns of uropathogens during the 2 study periods (P>0.05). Antibiotic susceptibility of the E. coli isolates to aztreonam, cefotetan, cefotaxime, ceftriaxone, cefepime, amikacin, and imipenem was >90% to trimethoprim/sulfamethoxazol, 49% and to ampicillin and ampicillin/sulbactam, 20-25%. Over the 2 study period, the E. coli susceptibilities to most antibiotics did not change: the susceptibility to cefuroxime increased from 74.1% to 95.5% (P=0.046) and that to ciprofloxacin increased from 59.3% to 86.4% (P=0.039). Conclusion:Empirical treatment with trimethoprim/sulfamethoxazole, ampicillin, and ampicillin/sulbactam alone appeared to be insufficient in childhood UTI because of the high resistance of E. coli and other gram-negative uropathogens. Antibiotics for empirical therapy should be selected based on the sensitivity and resistance pattern of uropathogens found in a particular region.

• Clinical and Experimental Pediatrics
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• v.49 no.3
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• pp.278-286
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• 2006

Purpose : Although suprapubic bladder aspiration(SBA) is the most reliable technique for identifying bacteriuria in young infant, no report has been published about the clinical manifestations of urinary tract infection(UTI) diagnosed by aspirated urine in Korea. This study was performed to examine clinical manifestations and related factors of UTI confirmed by a positive urine culture obtained by SBA in young infants. Methods : We reviewed medical records of 159 infants younger than six months of age, who had been admitted for UTI to Korea University Ansan Hospital from January 2002 to June 2005. Results : The male:female ratio was 5.1 : 1. The most common pathogen in urine culture was Escherichia coli(92.5 percent). Most of the gram-negative pathogens had high sensitivity to amikacin, or third generation cephalosporins and had low sensitivity to ampicillin, trimethoprim-sulfamethoxazole, or gentamicin. Hydronephrosis and vesicoureteral reflux(VUR) were present in 32.7 percent and 27.7 percent respectively. Renal cortical defects observed on DMSA scans were detected in 37.1 percent. Prolonged fever duration and hospital day, high erythrocyte sedimentation rate(ESR) and C-reactive protein(CRP) levels, hydronephrosis and VUR were related to the renal cortical defects(P<0.05). Rates of UTI-associated bacteremia and aseptic meningitis were 8.3 percent and 6.6 percent. Conclusion : Early differential diagnosis is very important in infants younger than 6 months of age with UTI because the clinical findings are non-specific and UTI-associated bacteremia and aseptic meningitis are concomitantly found. Because prolonged fever and higher ESR and CRP levels are risk factors of the renal cortical defects, radiologic evaluations and nephrologic follow-up were needed in identifying the predisposing congenital abnormalities and chronic renal scarring.

• Childhood Kidney Diseases
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• v.15 no.2
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• pp.163-171
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• 2011

Purpose : To evaluate the prevalence of vesicoureteral reflux (VUR) according to the timing of voiding cystourethrography (VCUG) in infantile urinary tract infection (UTI). Methods : The data of 134 infants (1-12 months) with renal cortical defect in $^{99m}Tc$-2, 3-dimercaptosuccinic acid ($^{99m}Tc$-DMSA) scan with a diagnosis of UTI in two hospitals from 2000 to 2010 were retrospectively analyzed. The VCUG was performed after 2 weeks from the diagnosis of UTI in Group I (n=68), and the VCUG was performed within 2 weeks from the diagnosis of UTI in Group II (n=66). Results : There were no significant differences between the two groups in the duration of fever, white blood cell count, C-reactive protein levels, and abnormalities in ultrasonography (P>0.05). There was no significant difference between the two groups in the prevelence of VUR, bilateral VUR, and severe VUR. VCUG-induced UTI was detected 16 (23.5%) of patients in whom the procedure was performed 2 weeks after the diagnosis, and none of VCUG-induced UTI occurred in those in whom the procedure was performed 2 weeks within the diagnosis. Conclusion : We conclude that the prevalence of VUR according to the timing of VCUG did not differ between the two groups in infantile UTI with renal cortical defect in DMSA scan. We also found that performing VCUG with antibiotics can decrease risk of VCUG-induced UTI.