Untreated asymptomatic bacteriuria in girls: I--Stability of urinary isolates.

OBJECTIVE--To assess the frequency of spontaneous changes of bacterial strains in patients with untreated asymptomatic bacteriuria. DESIGN--Retrospective analysis of samples from all patients with renal scarring and random sample of patients with normal kidneys. SETTING--Outpatient clinic for children with urinary tract infections. PATIENTS--54 Girls aged 3.3-15.5 years with untreated asymptomatic bacteriuria caused by Escherichia coli. INTERVENTION--None. END POINT--Change in bacterial strain. MEASUREMENTS AND RESULTS--Serotyping and electrophoretic analysis of sequential bacterial isolates, representing 151 patient years of untreated asymptomatic bacteriuria. A total of 24 changes of strain were identified. Eleven were related to medical interference such as treatment of other infections with antibiotics. CONCLUSIONS--Spontaneous changes of strain were uncommon, one change in 11.6 patient years, and thus are not a characteristic feature of the course of asymptomatic bacteriuria.     

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.     

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.     

Asymptomatic Significant Bacteriuria in the Non-pregnant Woman: II. Response to Treatment and Follow-up

Short courses of nitrofurantoin and ampicillin produced an immediate cure in 80% of adult non-pregnant bacteriuric women. Of the subjects so treated, 55% remained cured at the end of one year. Over the same follow-up period 36% of untreated bacteriuric women developed a spontaneous remission of bacteriuria. Treatment failed to prevent the development of symptomatic infection, and the reinfections which followed successful treatment were more commonly associated with the development of symptoms than the persistent or relapsing infections in untreated or unsuccessfully treated subjects.It is concluded that a search for bacteriuria in non-pregnant women is unlikely to be of value as a preventive measure, since in many instances it fails to detect urinary tract infection at an early stage and since treatment by methods suitable for large-scale use is ineffective.     

Study of Childhood Urinary Tract Infection in General Practice

A study of bacteriuria was conducted among 426 of the 436 children under the age of 13 in a general practice in north-west London. Three girls and one boy were found to have asymptomatic bacteriuria, and a further girl with bacteriuria presented with abdominal pain and fever. The calculated incidence of urinary tract infection was 1·4% per annum. Most of the childhood urinary infections in this practice occurred before the age of 5 years, and the incidence of significant bacteriuria in this age group was 4·9% per annum. Five other children (four girls and one boy) in the practice were known to have had proved urinary tract infection. Of the total of eight children known to have had significant bacteriuria and investigated radiologically, three girls and two boys had radiological abnormalities in the urinary tract.Pyuria and proteinuria did not prove to be useful in the prediction of asymptomatic bacteriuria. Urinary tract infection with renal tract abnormality was found in this practice to be at least five times as common as diabetes in childhood.     

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.     

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.     

Characterization of adhesion associated surface properties of uropathogenicEscherichia coli

Escherichia coli was isolated from the urine of patients with pyelonephritis, with urinary tract infections other than pyelonephritis and with asymptomatic bacteriuria. Surface properties of the strains were analyzed by the salting-out aggregation test (SAT), hydrophobic interaction chromatography (HIC), Congo red binding (Crb), agglutination of erythrocytes (MRHA) and latex particles covered by digalactoside (PF) and by adherence to tissue culture cells. In addition, a DNA probe for thepap gene was used. The DNA probe detected the highest proportion of strains withpap gene in the group of patients with pyelonephritis, lower in the urinary tract infections other than pyelonephritis and the lowest in the group with asymptomatic bacteriuria. Tests for P-fimbriae (PF, MRHA) showed a similar distribution. Hydrophobicity measured by SAT and by HIC did not show differences among the tested groups of strains. The results suggest that factors other than the P-fimbriae and hydrophobicity may contribute to the persistence ofE. coli in the urinary tract.     

Efficacité comparée de l'antibioprophylaxie par la céfoxitine en une ou trois doses dans la césarienne.

To compare the effectiveness of three doses and of a single dose of cefoxitin, a second-generation cephalosporin, in preventing infection after nonelective cesarean section, we carried out a prospective study in 255 women who underwent the procedure between March 1983 and February 1985. The rate of postoperative infection was 7% in the group that received three doses and 8% in the one-dose group. The sensitivity and specificity of perioperative cultures were low. The rate of asymptomatic bacteriuria was high, at 20%, but few symptomatic urinary tract infections were found. Routine antibiotic prophylaxis with a single dose is suggested for all nonelective cesarean sections.     

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.     

Six year follow up of infants with bacteriuria on screening.

OBJECTIVE--To determine the value of screening for bacteriuria in infants with special emphasis on the natural course of untreated asymptomatic bacteriuria, renal growth, and renal damage. DESIGN--Prospective six year follow up of infants with bacteriuria on screening in an unselected infant population. SETTING--Paediatric outpatient clinic. PATIENTS--50 Infants (14 girls, 36 boys) with bacteriuria on screening verified by suprapubic aspiration from an unselected population of 3581 infants in a defined area of Gothenburg. INTERVENTIONS--Children with asymptomatic bacteriuria and normal findings on initial urography were untreated, although other infections were treated. MAIN OUTCOME MEASURES--Culture of urine and determination of C reactive protein concentration every six weeks for the first six months after diagnosis, every three months from six months to two years, and every six months between two and three years; thereafter yearly urine culture. Evaluation of renal concentrating capacity with a desmopressin test; radiological examination, including first and follow up urography and micturition cystourethrography without antibiotic cover; and measurement of renal parenchymal thickness and renal surface area. RESULTS--Of the original 50 infants, 37 (12 girls, 25 boys) were followed up for at least six years. Two infants developed pyelonephritis within two weeks after bacteriuria was diagnosed; the others remained free of symptoms. 45 Infants were untreated; the bacteriuria cleared spontaneously in 36 and in response to antibiotics given for infections in the respiratory tract in eight. Recurrences of bacteriuria were observed in 10 of the 50 children, of whom one had pyelonephritis. No child had more than one recurrence. At follow up urography in 36 of the 50 children (9 girls, 27 boys) after a median of 32 months no child had developed renal damage. First samples tested for renal concentrating capacity showed significantly higher values than those from a reference population (mean SD score 0.50, 95% confidence interval 0.21 to 0.79; p less than 0.001), but the last samples showed no significant difference (mean SD score 0.08, -0.24 to 0.40; p greater than 0.05). CONCLUSIONS--Mass screening for bacteriuria in infancy results primarily in detection of innocent bacteriuric episodes and is not recommended.     

Asymptomatic Urinary Tract Infection in Gynaecological Outpatients

In this study mid-stream specimens of urine were collected from all new patients attending a gynaecological outpatient department and tested for significant bacteriuria. Those having an asymptomatic infection were folloWed up, treated, and investigated adiologically.Of 1,506 women screened for bacteriuria 82 (5·4%) were found to have a persistent infection. The predominant organism was Escherichia coli, present in 83% of infections. Treatment with sulphonamides produced a good cure rate, which was improved by ampicillin given to failures. Some patients, however, had infections that persisted or recurred despite several antibiotics. The radiological investigations showed that a high proportion of women with asymptomatic urinary infection had severe renal disease which was quite symptomless. This was more pronounced in those with persistent or recurrent infections.     

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.     

Urinary tract infections treated with single dose of short-acting sulphonamide.

In a prospective study 29 patients with urinary tract infections caused by sulphonamide-sensitive organisms were treated with a single oral dose of the short-acting sulphonamide sulphafurazole. Twenty-seven (93%) of the 29 patients--and possibly all 29--were cured of their infections. There was no difference in the recurrence rates after single-dose treatment and treatment for 10 days or more. Six out of eight strains of Escherichia coli causing early recurrences were sensitive to sulphonamides. These results suggest that uncomplicated infections may safely and successfully be treated by a single oral dose of a short-acting sulphonamide.     

Lower urinary tract infections from external beam radiation therapy in prostate cancer: A single institution experience

External beam radiation therapy (EMRT) is effective for the treatment of localized prostate cancer. Lower urinary tract infections (LUTIs) are considered one of the main possible adverse events related to External beam radiation therapy. Here we analyzed the incidence of LUTI during EMRT. Urinary tract infection was assumed when the findings of bacteriuria exceeded 100,000 units/mL, accompanied by specific cystitis symptoms. Among the total 540 analyzed patient, 208 (38.5%) developed a LUTI. E. coli was the main microorganism involved in LUTIs (102, 49.04%) with 8 cases of a combination between E. coli and another germ. In conclusion, a risk of urinary infections in cancer patients treated with pelvic radiotherapy was observed, in order to reduce the use of antibiotic resistance, preventive treatment with non-antibiotic agents 5 are warranted.     

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.     

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.     

Is screening for bacteriuria in pregnancy worth while?

A total of 4470 pregnant women were screened for bacteriuria by the dipslide method and significant growth found in 226 (5.1%). In 198 cases the urine was re-examined, in 119 by using suprapubic aspiration or catheterisation (62 (52%) samples contained bacteria) and in 79 by using midstream urine samples (26 (33%) samples contained greater than 10(8) colony forming units/1), showing the maximum prevalence of confirmed bacteriuria to be 2.6%. Overt urinary tract infection developed later in four of 80 patients with proved bacteriuria who had been given antibiotics, in one of eight untreated patients with bacteriuria, in one of 110 patients with unconfirmed bacteriuria, and in one of 226 non-bacteriuric controls. A history of urinary tract infection was given by 18% of controls and 42% of women with confirmed bacteriuria. Screening for bacteriuria and treatment with antibiotics to prevent later overt infection is expensive. Whether it is worth while and cost effective depends largely on the prevalence of bacteriuria in the local population and the proportion who develop overt infection. The screening and treatment programme reported here appeared to prevent only six cases of overt infection.     

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.