Contamination rates of different urine collection methods for the diagnosis of urinary tract infections in young children: An observational cohort study

Aims: The optimal method for diagnostic collection of urine in children is unclear. National Institute of Health and Clinical Excellence recommend specimens taken by clean catch urine (CCU) for identification of urinary tract infection (UTI). We investigated contamination rates for CCU, suprapubic aspiration (SPA), catheter specimen urine (CSU) and bag specimen urine (BSU) collections. Method: Retrospective observational cohort study with review of microbiology data and medical records at a large tertiary children's hospital. We reviewed urine culture growth from consecutive first urine specimens of children aged <2 years, over a 3-month period in 2008. Patient demographics, collection method, location (emergency department, inpatient ward), culture growth, history of UTI, urogenital tract abnormality and antibiotic use were assessed. Contamination rates for collection methods were compared using logistic regression. Results: Urine culture specimens of 599 children (mean age 7.0 months, 54% male) were included. There were 34% CCU, 16% CSU, 14% SPA, 2% BSU and 34% with unknown sample method. Contamination rates were 26% in CCU, 12% in CSU (odds ratio (OR) 0.4, 95% confidence interval (CI) 0.2-0.8) and 1% in SPA (OR 0.03 95% CI 0.0-0.3). Concurrent antibiotics use was associated with a lower contamination rate. Contamination rates were not associated with age, sex, location, history of UTI or urogenital abnormalities. Conclusion: Contamination rates in CCU are much higher than in CSU and SPA samples. Ideally, SPA should be used for microbiological assessment of urine in young children. Collection procedures need to be optimised if CCU is used.     

Recomendaciones sobre el diagnóstico y tratamiento de la infección urinaria

Urinary tract infection (UTI) is defined as the growth of microorganisms in a sterile urine culture in a patient with compatible clinical symptoms. The presence of bacteria without any symptoms is known as asymptomatic bacteriuria, and does not require any treatment. In neonates and infants, fever is the guiding sign to suspecting a UTI. Classic urinary tract symptoms become more important in older children. Urine cultures collected before starting antibiotics is always required for diagnosis. Clean-catch (midstream) specimens should be collected for urine culture. In the case of non-toilet-trained children, specimens must be obtained by urinary catheterisation, or suprapubic puncture in neonates and infants. Specimens collected by urine bag should not be used for urine culture. There are no significant differences in the clinical evolution and prognosis between oral versus short intravenous followed by oral antibiotic. Empirical antibiotic therapy should be guided by local susceptibility patterns. Second-generation cephalosporin (children under 6 years) and fosfomycin trometamol (over 6 years), are the empiric therapy recommended in this consensus. In the case of pyelonephritis, recommended antibiotic treatment are third-generation cephalosporins (outpatient care) or, if admission is required, aminoglycosides. Ampicillin should be added in infants less than 3 months old. Antibiotic de-escalation should be always practiced once the result of the urine culture is known.     

Accuracy of clean-catch urine collection in infancy

OBJECTIVE: To compare the accuracy of cultures of urine obtained by clean-catch urine (CCU) collection and suprapubic aspiration (SPA) in infants. DESIGN: Prospective case series undertaken in a pediatric teaching hospital and associated neonatal unit. Fifty-eight paired urine cultures (CCU collection and SPA) were obtained from 49 infants with suspected urinary tract infection. The primary outcome measure was the presence or absence of significant bacteriuria on both CCU collection and SPA; secondary outcome measures were the success of SPA with ultrasound guidance compared with aspiration without ultrasound guidance. Statistical analysis was done by using a chi(2) test. RESULTS: A false-positive rate of 5% and a false-negative rate of 12% were recorded. Sensitivity was 88.9% (95% CI 65.3-98.6), and specificity was 95.0% (95 CI% 83.1-99. 4). Ultrasound-assisted SPA was successful in 26 of 28 patients (93%) and in 13 of 21 patients (62%) when SPA was performed without ultrasound (chi(2) = 7.08, P =.008). CONCLUSIONS: We conclude that there is a good association in results of culture of urine obtained by CCU collection and SPA and would encourage the use of the CCU technique.     

Follow-up urine cultures and fever in children with urinary tract infection

BACKGROUND: The American Academy of Pediatrics practice parameter for urinary tract infection suggests a repeat urine culture if the expected clinical response is not achieved within the first 48 hours of therapy. The utility of repeat urine cultures and clinical significance of fever at 48 hours is unclear. OBJECTIVES: To determine the frequency of positive repeat urine cultures in children admitted to the hospital with urinary tract infection, and to describe the fever curves of children admitted to the hospital with urinary tract infection. DESIGN AND METHODS: We reviewed all cases of urinary tract infection in children 18 years and younger who were admitted during a 5-year period to Children's Hospital of Wisconsin (Milwaukee). We recorded temperatures from hospital admission to discharge, age, sex, initial and follow-up culture results, antibiotics received, imaging performed, and medical history. RESULTS: Urinary tract infection was identified in 364 patients, and 291 (79.9%) had follow-up urine cultures. None were positive. Follow-up cultures produced 21,388.50 US dollars in patient charges. Fever lasted beyond 48 hours in 32% of patients. Older children were more likely to have fever beyond 48 hours. CONCLUSIONS: Follow-up urine cultures were of no utility in children hospitalized for urinary tract infection, including those with fever lasting beyond 48 hours or those with an underlying urologic disease. Fever beyond 48 hours is common and should not be used as a criterion for obtaining a repeat urine culture. These conclusions are valid for children with vesicoureteral reflux. Such an approach would result in significant cost savings.     

SCORING OF URINARY FINDINGS AS AN AID IN DIAGNOSIS FOR CHILDHOOD URINARY TRACT INFECTION

Abstract. Pylkkänen, J., Vilska, J. and Koskimies, O. (The Children's Hospital, University of Helsinki, Finland). Scoring of urinary findings as an aid in diagnosis for childhood urinary tract infection. Acta Paediatr Scand, 70: 875, 1981.-To improve diagnostic accuracy of urinary tract infection in infants and children a simple score is described. 213 patients with suspect urinary tract infection underwent a diagnostic work-up including 2 consecutive clean-voided urine samples, and a suprapubic bladder aspirate as a diagnostic reference. The uncentrifuged clean-voided urine specimens were scored separately for microscopic leucocyte and bacterial count as well as for quantitative bacterial culture. The scores obtained were added together and a diagnostic scheme was created. After this scheme had been tested in 50 consecutive symptomatic urinary tract infections, it was possible to start therapy in 48 patients following the microscopic examination of 2 consecutive clean-voided urine samples from each. Likewise, 44 of 50 asymptomatic urinary tract infections were diagnosed by this scheme, after the urine cultures had been obtained. The scheme may be a useful aid in diagnosing urinary tract infection in infants and children, in case of equivocal urinary findings in particular.     

Diagnosis and management of urinary tract infection in children

A young child presents to their primary health provider with fever and irritability. How likely is a urinary tract infection? How should a urine sample be collected? How accurate are urinary dipsticks and microscopy compared with culture for the diagnosis? What route and type of antibiotics should be used? What imaging is indicated? Diagnosing and treating children with urinary tract infection presents many questions. This review summarises the most relevant recent primary studies, systematic reviews and guidelines.     

小儿泌尿系感染277例临床分析

目的探讨小儿泌尿系感染的临床特点及致病菌的分布和耐药情况,为临床诊断治疗提供依据。方法对1998—2006年首都医科研究所附属儿童医院肾脏病房收治的277例泌尿系感染患儿的临床特点、实验室检查、治疗及转归进行回顾性分析。结果145例尿培养前未应用过药物的患儿其尿培养阳性率为62.07%,132例培养前应用过药物的患儿其阳性率为20.45%,两者差异有统计学意义(P<0.05)。尿培养结果中大肠埃希菌有94例,对丁胺卡那霉素和头孢西丁的敏感率均在90%以上。结论抗生素的应用会大大降低尿培养的阳性率。大肠埃希菌为泌尿系感染的常见致病菌,头孢西丁可作为小儿泌尿系感染的首选用药。对首次发病的泌尿系感染患儿进行相应的影像学检查以排除一些潜在的病因是十分必要的。     

Single-Dose Netilmicin Therapy of Complicated and Uncomplicated Lower Urinary Tract Infections in Children

ABSTRACT. Thirty children (age 3 months to 10 years) with complicated and uncomplicated lower urinary tract infections were treated with a single intramuscular injection of netilmicin 4.5 mg/kg. The diagnosis of lower urinary tract infection was based on the absence of fever and the presence of normal values for erythrocyte sedimentation rate, C-reactive protein concentration and urinary excretion of N-acetyl-ß-D-glucosaminidase. Follow-up urine cultures in all children demonstrated a cure rate of 97 % and reinfection and relapse rates each of 7 % respectively. The subgroup (12 children) with radiological abnormalities of urinary tract showed a cure rate of 92 %, and reinfection and relapse rates of 9 % respectively. The rates of cure, reinfection and relapse in the complicated and uncomplicated urinary tract infections were not statistically different ( p >0.05). A pharmacokinetic study (performed in 5 children) demonstrated that netilmicin urinary concentrations were over the MIC's of the infecting organisms up to 96 hours after the single-dose injection. Netilmicin was well tolerated and no side effects appeared during treatment. Single-dose netilmicin therapy is an effective and safe regimen for complicated and uncomplicated urinary tract infections in children. The response to single-dose netilmicin therapy seems to be related to its prolonged urinary elimination.     

Single-dose netilmicin therapy of complicated and uncomplicated lower urinary tract infections in children

Thirty children (age 3 months to 10 years) with complicated and uncomplicated lower urinary tract infections were treated with a single intramuscular injection of netilmicin 4.5 mg/kg. The diagnosis of lower urinary tract infection was based on the absence of fever and the presence of normal values for erythrocyte sedimentation rate, C-reactive protein concentration and urinary excretion of N-acetyl-beta-D-glucosaminidase. Follow-up urine cultures in all children demonstrated a cure rate of 97% and reinfection and relapse rates each of 7% respectively. The subgroup (12 children) with radiological abnormalities of urinary tract showed a cure rate of 92%, and reinfection and relapse rates of 9% respectively. The rates of cure, reinfection and relapse in the complicated and uncomplicated urinary tract infections were not statistically different (p greater than 0.05). A pharmacokinetic study (performed in 5 children) demonstrated that netilmicin urinary concentrations were over the MIC's of the infecting organisms up to 96 hours after the single-dose injection. Netilmicin was well tolerated and no side effects appeared during treatment. Single-dose netilmicin therapy is an effective and safe regimen for complicated and uncomplicated urinary tract infections in children. The response to single-dose netilmicin therapy seems to be related to its prolonged urinary elimination.     

THE LENGTH OF ANTIMICROBIAL THERAPY IN UPPER VS. LOWER URINARY TRACT INFECTION OF CHILDHOOD

Abstract. Pylkkänen, J., Vilska, J. and Koskimies, O. (The Children's Hospital, University of Helsinki, Helsinki, Finland). The length of antimicrobial therapy in upper vs. wer urinary tract infection of childhood. Acta Paediatr Scand, 70: 885, 1981.-235 infants and children were randomized to a 10-day and 42-day treatment group and followed-up for 12 months after their first urinary tract infection. The anatomical level of each symptomatic infection was determined using simple laboratory criteria. The two regimens prescribed were equally effective in eradicating the infection, but after the discontinuation of the 10-day treatment with sulfafurazole, 17 (23%) of 73 patients with their first upper urinary tract infection experienced a recurrence within one month, as compared to only one (1) of 76 subjects in the 42-day therapy group. After the phase of early recurrence, there was no difference in recurrence rate between these groups. The early recurrences were associated with the patient's early age and a short duration of symptoms before therapy. The recurrence rate of first lower UTI after 10-day therapy was significantly lower than that after 42-day treatment. The duration of antimicrobial therapy for childhood urinary tract infection should be adjusted according to the patient's age and the anatomical level of the infection. 10-day treatment may not be sufficient to prevent early recurrence of pyelonephritic infections in infants under 6 months of age.     

Urine culturing technique in febrile infants

During the period from July to November 1984, 265 consecutive febrile infants younger than one year of age were evaluated in a pediatric emergency department. None had a source of infection on physical examination, and all were admitted with the diagnosis of "rule out sepsis." During the month of July, all patients with positive urine culture results had their urine sample collected by bag. In no instance was there a clinical diagnosis of urinary tract infection because of the presence of contaminant bacteria. A program was instituted on August 1, 1984 which encouraged the utilization of either bladder catheterization or suprapubic aspiration techniques, and discouraged bag collection technique for culturing urine. Over the next four months, catheterization and suprapubic aspiration techniques increased from 0 to 72%; bag technique decreased from 100 to 27%. Also, during this period the incidence of urinary tract infection increased to 5.53%. Seventy-five percent of patients with urinary tract infection had an initial urinalysis with less than 5 to 10 white blood cells/HPF, and 60% had an initial urine specific gravity of less than or equal to 1.005. Eighty-seven percent of infants with a positive urine culture result collected by bag technique revealed a mixture of more than three organisms. The technique utilized for collecting urine for culture in infants has a major impact on the incidence of urinary tract infection. The absence of pyuria is not a reliable indicator of the absence of urinary tract infection. Infants with urinary tract infection may have a transient loss in urine concentrating ability early in the course of their infection.     

小儿神经源性膀胱伴膀胱输尿管反流临床特点分析

目的 探讨神经源性膀胱(NB)患儿伴膀胱输尿管反流(VUR)的临床特征,为其临床早期诊断及治疗提供参考依据.方法 收集2014年1月至2019年12月于儿童肾内科收治并诊断为NB伴尿路感染的26例患儿的临床资料,根据有无VUR分为反流组(11例)与无反流组(15例),分析比较两组的临床特点.结果 相比无反流组,反流组患...     

Urinary tract infection: correlation of pyuria,bacteriuria with urine culture

Three hundred cases were analysed to find out value of direct smear examination, pus cell count and their correlation with culture method for diagnosis of urinary tract infection in children. Of 132 specimens with significant pyuria in uncentrifuged urine, and 102 specimens with significant pyuria in centrifuged urine, 54(40.9%) and 42(41%) cases respectively showed absence of bacteriuria. There was no satisfactory correlation between pyuria and bacterial colony count. Gram stain smear examination of the centrifuged urine showed high correlation with bacterial count in urine cultures. This is a good method in the absence of microbiology laboratory for the diagnosis of urinary tract infection.     

儿童泌尿道感染诊治规范

泌尿道感染(UTI)是儿童最常见的感染性疾病之一。儿童UTI的临床症状可不典型,需结合尿沉渣分析与尿细菌学检查诊断,必要时需完善影像学评估有无泌尿系统发育畸形等。一旦诊断UTI需给予敏感抗菌药物治疗,抗菌药物选择应结合患儿一般情况、所在地区耐药发生率、既往用药史、尿细菌学药敏结果综合判断。此外,UTI并膀胱输尿管反流的...     

A comparison of the initial to the later stream urine in children catheterized to evaluate for a urinary tract infection

BACKGROUND: To avoid potential contamination, it is recommended that the first few drops of urine be discarded when obtaining a catheterized urine sample from a child being evaluated for a urinary tract infection (UTI). The existing evidence to make such a recommendation is scant. Our goal, therefore, was to determine whether the urinalysis, Gram stain, and culture results were significantly different from the initial and later urine samples collected from catheterized children. METHODS: A prospective diagnostic discrimination between early and later urine samples was conducted on a convenience sample of pediatric patients being evaluated for a UTI in an urban emergency department. Results of the urinalysis, Gram stain, and quantitative culture were compared between the early and later stream urine samples. RESULTS: Data from 86 children were analyzed. Four of 80 patients had a false identification of low colony count bacteruria from the early but not from the later stream. For patients with negative cultures, the early stream was also more likely to falsely identify > or =5 wbc/hpf (P<0.01) or bacteruria (P<0.05) on urinalysis than the later stream. CONCLUSIONS: There is a small but potentially meaningful contamination of the early stream urine compared with the later stream in young children catheterized to evaluate for a urinary tract infection.     

Urinary tract infection: The urological perspective

Urinary tract infection in babies often presents with non specific symptoms and signs. It must be considered in the differential diagnosis of a febrile sick baby or any baby with failure to thrive. In a significant proportion of babies with recurrent urinary tract infection, urological abnormality is demonstrable. The diagnosis of urinary tract infection is confirmed by the presence of pus cells and growth of microorganism in a fresh urine specimen. The voidoing history and detailed ultrasound examination in the baby including a post void evaluation of the upper and lower urinary tract can lead to the possible diagnosis in the majority. Antibiotic therapy for urinary tract infection should be followed by consideration about the need for urinary drainage at the appropriate level, particularly in cases where resolution is delayed despite antibiotics. There is a role for prophylactic antibiotics after the resolution of acute infection, at least until detailed evaluation several weeks after the acute episode, has excluded any abnormality. Micturating cytourethrogram is usually done under antibiotic cover and better done in centres with facility for fluoroscopic examination. Isotope studies have to be evaluated in the light of inherent limitations. Transient urodynamic abnormality of the urinary bladder in infancy is being increasingly recognized and should be the subject of evaluation in specific circumstances. A multidisciplinary team improves the quality of investigations, subsequent interpretation and long term care of these children. A large majority of urological abnormality in infancy and early childhood can be effectively managed by endocopic procedures. Temporary urinary diversion may be required in a small proportion. Urological reconstruction should be approached with caution, after a detailed analysis of the evolving urological tract in a baby. An aggressive approach to early diagnosis and appropriate treatment of urinary tract infection and any underlying abnormality, has been shown to significantly reduce the incidence of chronic renal failure in long term longitudinal studies in children.     

Localization and therapy of urinary tract infections of childhood.

One hundred four patients with 124 episodes of urinary tract infection were studied. Serum C-reactive protein (CRP) was determined on diagnosis of each patient. Children with a CRP equal to or greater than 30 micrograms/ml (CRP-pos) differed significantly from those with values less than 30 micrograms/ml (CRP-neg) in age, clinical presentation, K type of Escherichia coli causing disease, frequency or radiographic abnormalities, and presence of antibody coating of bacteria in the urinary sediment. E. coli K1 strains caused disease significantly more often in CRP-pos than in CRP-neg patients, and children with K1 infections were younger than those with non-K1 infections. The antibody-coated bacteria test was neither sensitive nor specific for localization of infection in pediatric patients. Determination of K1 antibody concentrations in serum and urine of E. coli K1-infected children provided data supporting the measurement of CRP as one means of localizing urinary tract infections. Patients with CRP-neg infections were treated as successfully with four days of antimicrobial therapy as with ten days.     

Is urethral catheterization a successful alternative to suprapubic aspiration in neonates?

OBJECTIVE: To compare urine collection by urethral catheterization with suprapubic aspiration in a neonatal intensive care unit. METHODOLOGY: All urine collections were documented, the collection methods attempted recorded and success rates calculated. The incidence of contaminated specimens was determined. The infants ranged in weight from 570 g to 4180 g and in gestation from 24 to 44 weeks. RESULTS: Thirty-two out of 65 (49%) suprapubic aspirations were successful. Overall 33/42 (77%) of catheterizations were successful, 12/18 (67%) were successful when following an unsuccessful SPA. No SPA was contaminated compared to 7/22 (22%) of the catheter specimens. Urinary tract infection was present in 4/63 (6.3%) infants. There were no complications following catheterization. CONCLUSIONS: Urethral catheterization is a useful and safe alternative to suprapubic aspiration, but suprapubic aspiration remains the method of first choice.     

The Incidence of Erythrocyte Pi Antigen Retention in Children With Urinary Tract Infection

The erythrocyte P, antigen was observed in 91.7, 70.6, 56.7 and 62.5%, respectively, of children with upper urinary tract infection, symptomatic and asymptomatic urinary tract infections and cases responsive to initial therapy in which the abnormal urinary findings disappeared with the administration of antibiotics given despite the absence of bacteriuria. These values were significantly high (P<0.001, 0.001, 0.01, 0.001, respectively) compared with healthy controls (29.0%). In cases where initial antibiotic therapy was effective despite no significant bacteriuria, the presence of Gal cd– 4 Gal receptor in large quantity on the surface of the mucosa of the urinary tract was suggested, just as in the typical case of urinary tract infection with bacteria in the urine. No significant difference was observed in the incidence of P1 antigen in the peripheral blood of sick children according to the clinical symptoms and urinary findings in typical cases of urinary tract infection and cases responsive to initial antibiotic therapy.     

Parental reporting of smelly urine and urinary tract infection.

BACKGROUND: Parents often report that young children have "smelly urine" or a particular urinary odour. There is little evidence that these observations are relevant to the diagnosis of urinary tract infection (UTI). AIMS: To determine whether parental reporting of smelly urine is of any relevance to the diagnosis of UTI in children less than 6 years of age. METHODS: Parents whose children were having urine collected as part of their admission to a large district hospital were given a simple questionnaire to complete regarding the current smell of their child's urine. Parents were asked whether their child's urine smelled different from usual or had a particular smell. Microscopy and culture results of the child's urine were compared to their parent's questionnaire answers to see if there was a association between parental reporting of a different or particular urine smell and a diagnosis of UTI. RESULTS: One hundred and ten questionnaires and urine samples were obtained. Fifty two per cent of parents thought that their child's urine smelled different from usual or had a particular smell. Only 6.4% of children were diagnosed as having a UTI. There was no statistically significant association between parental reporting of abnormal urine smell and diagnosis of UTI. CONCLUSION: In determining whether a young child has a UTI, asking parents about urine smell is unlikely to be of benefit.