Incidence and outcome of symptomatic urinary tract infection in children.

The incidence of symptomatic urinary tract infection in 2879 children aged under 15 years was studied over 18 months in a single general practice. Infection was diagnosed if bacterial counts in three consecutive samples exceeded 100,000/ml. The incidence of urinary tract infection was 1.7 per 1000 boys at risk per year and 3.1 per 1000 girls. These values are lower than those of comparable studies, possibly because of the stricter diagnostic criterion used in the study. Urinary pus cell counts were also carried out and sometimes found to be misleading. Of the 14 children found to have an infection, three had a radiological abnormality. Five of the children had a recurrence of infection within the first two years, and one an asymptomatic bacteriuria seven years after diagnosis. Only six out of 34 children presenting with dysuria had infected urine, and an association was discovered between abacterial dysuria (or the urethral syndrome) in the remainder and a concurrent upper respiratory tract infection. All children should undergo radiological investigation after their first confirmed infection. Diagnosis and management could be improved by providing all general practitioners with a semiquantitative method of urine culture such as the dip slide.     

Asymptomatic Bacteriuria in Girl Entrants to Dundee Primary Schools

During the statutory medical examination on entrance to primary school 943 5-year-old girls were screened for asymptomatic bacteriuria. A prevalence of 2·1% was found. None of the 20 children with asymptomatic bacteriuria was recognized by the parents as having a urinary infection, though 14 of them had symptoms of lower urinary tract infection. In 16 of the children with bacteriuria either the intravenous pyelogram or the micturating cystogram was abnormal. In 12 the height and weight were below the 25th percentile, and in this group the most severe radiological changes were found.Though the significance of asymptomatic bacteriuria is unknown, these results confirm that in this age group it is often associated with a urinary tract abnormality.     

Trial evaluation of familial asymptomatic bacteriuria]

Between September 1, 1987 and December 1, 1988, 57 cases of asymptomatic bacteriuria were distinguished in the group of 2,898 schoolgirls, aged between 15 and 20 years (mean 16.7 years). For screening purposes Griess'test modified by Sleigh was used. Bacteriologic tests have shown, that 12 out 57 mothers (21.05%) and 5 out of 39 sisters (12.82%) suffered from asymptomatic bacteriuria, while this pathology was diagnosed in 61 (2.10%) out of all control population, i.e. 66 girls. Incidence of the asymptomatic bacteriuria was 4.55% in the 66 mothers. The differences in the incidence of the infection between the whole population and mothers of the control group, and between sisters and mothers of girls with asymptomatic bacteriuria were statistically significant (p < .001 and p < .01, respectively). History of the urinary tract infections was significantly more frequent in girls with asymptomatic bacteriuria, their mothers and sisters than in the control group. Type of bacterial strains isolated from the urine, similar sanitary conditions in these families as well as the lack of ultrasonographically and renographically diagnosed urinary pathologies in 11 out of 13 girls whose mothers and sisters suffered from asymptomatic bacteriuria suggest that familial asymptomatic bacteriuria may have a genetic background.     

Epidemiology of urinary tract diseases in general practice

During a one-year morbidity survey of urinary tract diseases in general practice 741 cases were diagnosed. Only about half of all the patients with symptoms of urinary tract infection had significant bacteriuria. In young women urinary tract infections and symptoms from the urinary tract without bacteriuria—in particular urethritis—were found to predominate. In middle-aged women, the urinary tract symptoms were ascribed increasingly to genital prolapse, while incidence of urolithiasis was the highest in any group, and urinary tract infections became less frequent. The prevalence of urinary tract infection showed another increase in elderly women, and recurrent/chronic pyelonephritis, which occurs with a steadily increasing prevalence throughout all age groups, became common.In younger male urological patients diseases with symptoms of urinary tract infection without bacteriuria were predominant, whereas prostatitis and urinary tract infections were less frequent. In middle-aged men, urolithiasis was especially frequent, while an increasing proportion of elderly men had prostatic hypertrophy, urinary tract infections, and recurrent/chronic pyelonephritis.     

Untreated asymptomatic bacteriuria in girls: II--Effect of phenoxymethylpenicillin and erythromycin given for intercurrent infections.

OBJECTIVE--To investigate the effects of phenoxymethylpenicillin and erythromycin on urinary isolates from patients with untreated asymptomatic bacteriuria. DESIGN--Retrospective study of subgroup of patients from cohort followed up till the end of 1986. SETTING--Outpatient clinic for children with urinary tract infections. PATIENTS--51 Girls aged under 15 with untreated asymptomatic bacteriuria. INTERVENTIONS--Before 1982 intercurrent infections (mostly tonsillitis or otitis) were treated with phenoxymethylpenicillin; after 1982 erythromycin treatment was preferred. END POINTS--Change of bacterial strain in urinary tract and symptomatic recurrences of disease. MEASUREMENTS AND MAIN RESULTS--Bacteria identified by serotype and electrophoretic type and compared before and after antibiotic treatment. Bacteriuria eradicated and replaced by new strains in most patients treated with phenoxymethylpenicillin, leading to symptomatic recurrences in about 15%. Conversely, patients given erythromycin rarely showed change in bacteriuria and none suffered symptomatic recurrence. CONCLUSIONS--In girls with untreated asymptomatic bacteriuria the use of phenoxymethylpenicillin for intercurrent infections may lead to a change of urinary bacteria and leave them at substantial risk of acute pyelonephritis. With erythromycin this risk is small (2/20 courses in this series).     

Pathogenic characteristics of Escherichia coli strains in cases of asymptomatic bacteriuria and symptomatic urinary tract infections

The aim of this study was to examine if E. coli isolated from asymptomatic bacteriuria differed in pathogenic features from strains isolated from symptomatic infections of urinary tract. In this study 130 strains of E. coli isolated from women having asymptomatic bacteriuria and 112 strains isolated from patients with symptoms of urinary tract infection were examined. It was shown that E. coli isolated from patients with symptomatic urinary tract infection showed the more frequently ability to cause mannose-resistant haemagglutination of human erythrocytes, resistance to bactericidal activity of serum and haemolytic properties than those isolated from asymptomatic bacteriuria. These strains showed also the higher ability to adhere to Vero cells in tissue culture. Among E. coli strains isolated from persons with asymptomatic bacteriuria the pathogenic features were most frequently found in strains from healthy women and the most rarely in isolated from diabetic women.     

The role of E. coli adhesiveness in the pathogenesis and clinical course of urinary tract infections]

An infection with E. coli is the most frequent cause of the urinary infections in childhood. Virulence depends on several factors out of which a principal role is played by the adhesion of bacteria to the urinary tract epithelium. Such a property have E. coli strains with adherence mannose-positive fimbriae of type P with antigens recognizing and binding glycolipid receptors on epithelial cells in the urinary tract. Children with such infections owe their "sensitivity+" (10% of the population) to genetically determined large number o receptors binding E. coli strains. Incidence and clinical course of the urinary tract infections have been analysed in the group of 184 children. Moreover, sequelae of the urinary tract infections with E. coli have been analysed in dependence on E. coli strain characteristics, i.e. presence or absence of adherent fimbriae from cases of cystitis and significant asymptomatic bacteriuria. Considering pathogenesis of the urinary tract infections as the result of interactions between bacteria and host, antigenic properties of adherent fimbriae might be used for preparation of a vaccine preventing such infections.     

Clinical importance of significant asimptomatic bacteriuria in newborns and infants during early postnatal period

The aim of the study was to detect newborns at risk for developing renal impairment, and to point out the importance of significant asimptomatic bacteriuria in perinatal period and early infancy. Severe urinary tract anomalies are very often accompanied only by asimptomatic bacteriuria in perinatal period. Three urinalysis ware done after delivery. 212 newborns with significant asimptomatic bacteriuria underwent ultrasound examination, and were followed up to three months. Those with normal findings and with passing bacteriuria in the first 2 months were excluded. Group of 52 newborns underwent radioisotope examination. Frequency of urinary tract anomalies in newborns was 34.6%. Increased risk for renal impairment had children with urinary tract anomalies in close family, urinary tract infection or bacteriuria, EPH gestosis and prepartal symptoms of febrile infection in mother, children with IUGR, strangulated umbilical cord, prolonged jaundice and attacks of peripheral cyanosis in perinatal period.     

Retrospective study of children with renal scarring associated with reflux and urinary infection.

OBJECTIVE--To review the histories of children with bilateral renal scarring and severe vesicoureteric reflux to determine whether an improvement in early management might reduce the risk of scarring. DESIGN--Retrospective study of medical records and discussion with parents. SETTING--Outpatient departments of two teaching hospitals. PATIENTS--52 children aged 1-12 years participating in a randomised comparison of medical and surgical management. All had a history of symptomatic urinary tract infection. Two thirds presented with fever and two with hypertension or renal failure. In only one out of 32 children examined by antenatal ultrasonography was an abnormality suspected. RESULTS--There was delay in diagnosis or appropriate imaging or effective treatment of urinary infection in 50 of the 52 children. In 41 there was delay in diagnosis; there was delay in treating a confirmed infection in 45; no antibacterial prophylaxis was prescribed before imaging in 28; and investigation of the urinary tract was delayed in 33. The severity of scarring was significantly related to delay in diagnosis (chi 2 for trend 7.43, P = 0.01). Four children of mothers known to have reflux nephropathy were not investigated until they developed urinary tract infection. CONCLUSIONS--Efforts to reduce the incidence and severity of renal scarring should be directed towards rapid diagnosis and effective early management of urinary tract infection in infancy and childhood. Siblings and offspring of known patients with severe reflux nephropathy should be investigated for reflux.     

Genetic determinants of Escherichia coli pathogenicity isolated from urine and feces of children with different clinical variants of urinary system infection

In the process of examination of 156 children of different age groups 176 E. coli cultures were isolated; of these, 98 cultures were isolated from acute cystitis and pyelonephritis patients, 28--from urine in cases of aysmptomatic bacteriuria, 30--from feces in cases of asymtomatc bacteriuria and intestinal dysbacteriosis, while 20 cultures--from feces of healthy children. In these bacteria the presence of genes associated with pathogenicity islets (PI) hlyA, hlyB, cnf-1, papC, sfaG and gene irp-2 (iron-regulated protein) was established with PCR. The detection rate of PI determinants in uropathogenic E. coli (UPEC) was shown to depend on the variants of the clinical manifestation of urinary tract infection. The total detection rate of PI gene fragments in UPEC cultures of different origin was indicative of their definitely less frequent occurrence in asymptomatic bacteriuria, observed simultaneously with intestinal dysbacteriosis, in comparison with acute urological infection. Practically the same detection rate of PI determinants in E. coli, isolated in asymptomatic bacteriuria in children, reflected high probability of genetic exchange in the above-mentioned fragments and made it possible to presume the existence of DNA sites, characteristic mainly of pathogenic clones. The established heterogeneity of the detection rate of PI determinants in E. coli clinical isolates requires further study.     

Development of renal scars in children: missed opportunities in management. South Bedfordshire Practitioners' Group.

OBJECTIVE--To assess the antecedent medical care of children with renal scars. DESIGN--Retrospective study of both general practice and hospital records. SETTING--12 Group practices in south Bedfordshire and the radiology and paediatric outpatient departments of a district general hospital. SUBJECTS--23 Children with renal scars (six boys, 17 girls) from the 12 group practices, identified from outpatient, radiology, and general practice records. MAIN OUTCOME MEASURES--Number of children in whom a diagnosis of urinary tract infection had been made without prior examination of a mid-stream specimen of urine; number of children who had had a confirmed urinary tract infection that had not been investigated further; number who had experienced delays in investigation or referral; and number who had received inadequate follow up. RESULTS--In all, 11 of the children had received suboptimal medical care, but the management of the other 12 could not have been better. The most common error was failure to investigate possible urinary tract infections, but follow up of confirmed infections was also inadequate. These problems occurred in hospital as well as in general practice. CONCLUSION--Opportunities for intervention had been missed in nearly half of this sample of children with renal scars.     

A Comparative Study of the Triphenyltetrazolium Chloride (Uroscreen) Test and Conventional Methods for the Detection of Bacteriuria

Acute urinary tract infection may be preceded by and active pyelonephritis may be associated with asymptomatic bacteriuria. Treatment of asymptomatic bacteriuria may prevent or arrest active, chronic pyelonephritis and its sequelae. Consequently, there is a need for a reliable and simple screening procedure to detect asymptomatic bacteriuria in large segments of the population.The reliability and practicability of tests advocated for the detection of bacteriuria, including the new chemical triphenyltetrazolium chloride (T.T.C.) (Uroscreen) test, were evaluated. Reliability was assessed by correlating results of these tests with bacterial counts of tested urines. Significant bacteriuria is defined as the presence of 100,000 or more organisms per ml. of urine.The T.T.C. (Uroscreen) test was positive in 92.5% of cases of bacteriuria; there were 7.5% false-negative and 2.8% false-positive results. Bacteria on Gram-stained smear were found in 95.5% of the cases of bacteriuria and in 14.6% of those with non-infected urine; pyuria (more than three leukocytes per high-power field), in 60% of those with bacteriuria and in 15.9% of those with presumably non-infected urine. Bacteria were conspicuous in the urinary sediment in 91.1% of cases of bacteriuria and in 3.7% of presumably non-infected urines.The T.T.C. (Uroscreen) test fulfilled the criteria for a reliable and simple screening procedure. It should be used concomitantly with other screening tests when the urine is examined routinely.     

Biofilm formation by asymptomatic and virulent urinary tract infectious Escherichia coli strains

Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU) in humans. In contrast to uropathogenic E. coli (UPEC) that cause symptomatic urinary tract infection, very little is known about the mechanisms by which these strains colonize the urinary tract. Here, we have investigated the biofilm-forming capacity on abiotic surfaces of groups of ABU strains and UPEC strains in human urine. We found that there is a strong bias; ABU strains were significantly better biofilm formers than UPEC strains. Our data suggest that biofilm formation in urinary tract infectious E. coli seems to be associated with ABU strains and appears to be an important strategy used by these strains for persistence in this high-flow environment.     

Study of urinary tract infection in children in one health district.

OBJECTIVES--To determine the number of children who had urine specimens sent for culture, who had infections or sterile pyuria, and who were investigated further. To relate the laboratory findings to the results of imaging. DESIGN--One year survey of urine specimens submitted to a laboratory; review of previous and subsequent laboratory reports; review of the findings of imaging of the urinary tract. SETTING--Portsmouth and South East Hampshire health district. SUBJECTS--An estimated population of 89,086 children aged 12 years or under. MAIN OUTCOME MEASURES--Urine bacterial count and results of imaging. RESULTS--12,551 urine specimens were submitted from 7450 children, 3138 boys and 4312 girls. 2238 children had infection or sterile pyuria at least once during the study (13.9/1000 boys, 37/1000 girls). 996 (45%) of the children with infection or sterile pyuria underwent some form of imaging. 128 children who had infection or sterile pyuria were already known to have urinary tract abnormalities and 114 children had newly identified abnormalities (1.0/1000 boys, 1.5/1000 girls). 50 (44%) of the children with newly detected abnormalities had no pyuria and 48 (42%) had bacterial counts below 10(8)/l. Eight children who had sterile pyuria on presentation were found to have abnormalities on imaging. CONCLUSIONS--Urinary tract infection is much commoner in children than is widely believed. Low bacterial counts, the absence of pyuria, or a finding of sterile pyuria should not be disregarded.     

Neonatal Bacteriuria: A Prospective Study in 1,460 Infants

In a prospective study of 1,460 virtually consecutive neonates 14 (1%) were found to have bacteriuria, established by bladder puncture. Eleven were boys and three girls. Five of the infants with bacteriuria had symptoms suggestive of infection and were treated with antibiotics. The remaining nine were asymptomatic and remained so during a period of observation—five cleared their urine of bacteria without treatment, and four received antibiotics. Only one infant with bacteriuria had bacteraemia. Six infants had more than 10 white blood cells per mm³ in the bladder puncture urine and three had proteinuria. The blood urea was slightly raised in only two of the infants. The intravenous pyelogram was normal in all infants with bacteriuria but eight had slight or moderate vesicoureteric reflux when examined by micturating cystourethrography.     

Epidemiology of symptomatic infections of the urinary tract in children.

The epidemiology of symptomatic infections of the urinary tract in children and the factors that may alter the risk of infection are not well known. Numbers of children aged under 15 discharged from hospitals because of symptomatic infections of the urinary tract during 1978-84 were obtained from the database kept by the Finnish National Board of Health. Information on continuous treatment for recurrent urinary tract infections was obtained from records kept by the Social Insurance Institution on patients receiving free medicines. The yearly rate of attacks of symptomatic infections/1000 girls decreased significantly from 2.67 (95% confidence interval 2.52 to 2.82) in 1978 to 1.88 (1.76 to 2.01) in 1984. In boys the rate also decreased significantly, from 0.85 (0.77 to 0.93) in 1978 to 0.59 (0.52 to 0.66) in 1984. The period prevalence of free treatment/1000 girls decreased significantly from 7.80 (7.55 to 8.05) in 1978 to 5.30 (5.10 to 5.51) in 1984 but did not change significantly in boys. Although the findings may partly have been caused by changes in policies of admission to hospital, they suggest a decreasing trend in symptomatic urinary tract infections in childhood, which may be associated with changes in the care of infants.     

Three-day and ten-day chemotherapy for urinary tract infections in general practice.

The length of a course of antibiotic treatment for urinary tract infection varies with the habits of the prescriber. Many patients do not complete a course of treatment once their symptoms have subsided. In uncomplicated urinary tract infection among women seen in general practice a three-day course of amoxycillin was as effective as a 10-day course of the same drug in the same dose. Relief of symptoms was equal in both groups and bacteriuria was eliminated equally successfully in both regimens. There was no significant difference between the two groups in the incidence of side effects from the drugs. The financial saving which could accrue from adopting this therapeutic regimen would be significant.     

Pregnancies in women with and without renal scarring after urinary infections in childhood.

OBJECTIVE--To compare the outcome of pregnancy in women with and without renal scarring after childhood urinary infections with that in unmatched controls. DESIGN--Retrospective study of pregnancies in women prospectively followed up from their first recognised urinary infection. SETTING--Tertiary referral centre in Gothenburg. SUBJECTS--111 Women attending an outpatient clinic for women with urinary infection during 1975-83, of whom 41 (65 pregnancies) were studied (19 women with renal scarring (32), 22 without scarring (33)), and 65 controls (65) randomly selected and matched for parity, age, smoking habits, and date of delivery. MAIN OUTCOME MEASURES--Urinary infections and complications in pregnancy. RESULTS--The incidence of bacteriuria during first pregnancies was significantly greater in women with (9, 47%) and without (6, 27%) renal scarring after childhood urinary infection than in controls (1, 2%) (p less than 0.001, 0.01 respectively). Symptomatic infections were seen only among women with a history of urinary infection: four women with renal scarring (three of whom had vesicoureteric reflux) developed pyelonephritis and three cystitis, and one woman without scarring developed pyelonephritis. Mean blood pressure was higher among women with severe renal scarring than controls (4/11 v 3/44; p less than 0.05) before and during pregnancy. There was no significant difference in the incidence of pre-eclampsia, operative delivery, prematurity, or birth weight. CONCLUSIONS--Women with a history of previous urinary infections had a high incidence of bacteriuria during pregnancy, and those with renal scarring and persistent reflux were prone to develop acute pyelonephritis. The risk of serious complications in pregnancy, however, was not increased in women with severe renal scarring, possibly owing to their continuous clinical supervision.     

Prevalence and incidence of Helicobacter pylori Infection in a healthy pediatric population in the Lisbon area

Background: Helicobacter pylori is mainly acquired in childhood. Although adult studies reported a high prevalence of H. pylori infection in Portugal, the actual rate in children remains unknown. This study aimed to determine the prevalence and the incidence of H. pylori infection in an asymptomatic pediatric population of the Lisbon area and to correlate prevalence with sociodemographic determinants. Materials and Methods: Helicobacter pylori infection was determined by stool antigen test in 844 asymptomatic children (age 0–15 years; 49.4% boys). For the incidence study, H. pylori‐negative children in the prevalence study were followed‐up every 6 months over a 3‐year period. Results: The global prevalence of H. pylori infection was 31.6%, increasing with age (19.9, 37.0 and 51.5%, in age groups 0–5, 6–10, and 11–15, respectively), but was similar among genders (34.5% in boys and 28.4% in girls). Older age and attendance of nursery/kindergarten during preschool constituted independent risk factors. The overall estimated incidence was 11.6 per 100 child‐years (CY). Although 47.5% of children acquired H. pylori infection before 5 years of age, the mean age of acquisition was 6.3. The incidence of infection was similar among the three age groups (11.5, 13.0, and 10.5 per 100 CY, in age groups 0–5, 6–10, and 11–15, respectively). Conclusions: The prevalence of H. pylori infection in the Portuguese pediatric population is still high. Although this study confirmed that the highest acquisition rate occurs at young age, it showed that in high‐prevalence populations, older children can also acquire H. pylori infection at a rate similar to that of young children.     

Application of biotinylated and32P probes for detection of P-fimbriae in urinaryE. coli

Escherichia coli is the common causative agent of urinary tract infections. Twenty-six strains ofEscherichia coli were isolated from children with pyelonephritis, symptomatic urinary tract infections and asymptomatic bacteriuria. Biotinylated and³²P-DNA probes were prepared for detection of P-fimbriae in the isolates. Of the 13 strains isolated from patients with pyelonephritis 11 were positive for the presence of the P gene by both probes. Strains isolated from cases of symptomatic urinary tract infections revealed the presence of P gene only in three samples of the total of nine isolated. None of the isolatedE. coli strains from asymptomatic bacteriuria was found positive for the presence of the P gene. The biotynylated probe was simple and easily applicable in standard laboratory conditions and therefore the authors recommend it for use in diagnostic laboratories.