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.     

Suprapubic aspiration under ultrasound guidance in children with fever of undiagnosed cause.

OBJECTIVES--To assess the ease of use of suprapubic aspiration of urine under ultrasound guidance in babies with fever of uncertain cause and to assess the importance of bacterial counts and pyuria in relation to abnormalities of the urinary tract and the importance of pyuria in the absence of bacteriuria. DESIGN--Analysis of urine samples obtained by suprapubic aspiration in babies and children from July 1991 to June 1992. The clinical records of the children with bacteriuria and sterile pyuria were examined retrospectively. SETTING--Neonatal and paediatric wards of a district general hospital. SUBJECTS--508 babies and children who had fever of uncertain cause or were seriously ill. RESULTS--No difficulties arose in the collection of 545 specimens. Bacteria were isolated from the specimens of 44 children, 24 of whom had abnormalities of the urinary tract. The bacterial count was < 10(8)/l in 18 of the children with bacteriuria, 10 of whom had abnormalities. No white cells were seen in 22 of the 46 bacteriuric specimens; nine of the children with no pyuria had vesicoureteric reflux. 439 of the 499 non-bacteriuric specimens showed no white cells. 60 children had pyuria without bacteriuria. CONCLUSIONS--The use of ultrasound guidance simplifies suprapubic aspiration of urine in babies. Low bacterial counts may be associated with abnormalities of the urinary tract. Laboratory techniques capable of detecting such counts reliably should be used. Pyuria is absent in half of babies and very young children with bacteriuria. It rarely occurs without bacteriuria, and if it does an explanation should be sought.     

Bacterial profile and drug susceptibility pattern of urinary tract infection in pregnant women at University of Gondar Teaching Hospital, Northwest Ethiopia

ABSTRACT: BACKGROUND: Urinary tract infection (UTI) is a common health problem among pregnant women. Proper investigation and prompt treatment are needed to prevent serious life threatening condition and morbidity due to urinary tract infection that can occur in pregnant women. Recent report in Addis Ababa, Ethiopia indicated the prevalence of UTI in pregnant women was 11.6 % and Gram negative bacteria was the predominant isolates and showed multi drug resistance. This study aimed to assess bacterial profile that causes urinary tract infection and their antimicrobial susceptibility pattern among pregnant women visiting antenatal clinic at University of Gondar Teaching Hospital, Northwest Ethiopia. METHODS: A cross-sectional study was conducted at University of Gondar Teaching Hospital from March 22 to April 30, 2011. Mid stream urine samples were collected and inoculated into Cystine Lactose Electrolyte Deficient medium (CLED). Colony counts yielding bacterial growth of 105/ml of urine or more of pure isolates were regarded as significant bacteriuria for infection. Colony from CLED was sub cultured onto MacConkey agar and blood agar plates. Identification was done using cultural characteristics and a series of biochemical tests. A standard method of agar disc diffusion susceptibility testing method was used to determine susceptibility patterns of the isolates. RESULTS: The overall prevalence of UTI in pregnant women was 10.4 %. The predominant bacterial pathogens were Escherichia coli 47.5 % followed by coagulase-negative staphylococci 22.5 %, Staphylococcus aureus 10 %, and Klebsiella pneumoniae 10 %. Gram negative isolates were resulted low susceptibility to co-trimoxazole (51.9 %) and tetracycline (40.7 %) whereas Gram positive showed susceptibility to ceftriaxon (84.6 %) and amoxicillin-clavulanic acid (92.3 %). Multiple drug resistance (resistance to two or more drugs) was observed in 95 % of the isolates. CONCLUSION: Significant bacteriuria was observed in asymptomatic pregnant women. Periodic studies are recommended to check the outcome of asymptomatic bacteriuria and also monitor any changes in the susceptibility patterns of urinary tract pathogens in pregnant women.     

Use of urinary gram stain for detection of urinary tract infection in childhood

In this study, urinary culture, urinary Gram stain, and four tests within the urinalysis, leukocyte esterase, nitrite, microscopyfor bacteria, and microscopyforpyuria, were examined in 100 children with symptoms suggesting urinary tract infection. Our purpose was to determine the validity of the urinary Gram stain compared with a combination of pyuria plus Gram stain and overall urinalysis (positiveness of nitrite, leukocyte esterase, microscopy for bacteria, or microscopy for white blood cell). Of 100 children, aged two days to 15 years, 70 (70 percent) had a positive urinary culture: 40 girls (57 percent) and 30 boys (43 percent). Escherichia coli was the most common isolated agent. The sensitivity and specificity of the urinary Gram stain were 80 percent and 83 percent, and that of the combination of pyuria plus Gram stain 42 percent and 90 percent, and that of the overall urinalysis 74 percent and 3.5 percent respectively. Our findings revealed that neither method of urine screen should substitute for a urine culture in the symptomatic patients in childhood.     

Generalized symptoms in adult women with acute uncomplicated lower urinary tract infection: an observational study

Several generalized symptoms in acute lower urinary tract infection (UTI) have previously been identified in a qualitative study. The aim of the present study was to explore the frequency and distribution of generalized symptoms in adult women with acute uncomplicated lower UTI in general practice. A total of 398 women aged 18-87 years consulting for acute dysuria and/or urinary frequency were enrolled in an observational study and filled in a structured symptom questionnaire. A total of 252 of these had bacteriuria (>or= 10(5) uropathogens/mL). Generalized symptoms occurred frequently: feeling unwell 68%, week and tired 67%, irritable and restless 53%, and hot 52%. Other symptoms were voiding-related symptoms (dysuria 90%, urinary frequency 93%, urge 80%) and local, constant symptoms (pressure in the genital area 73%, suprapubic discomfort 68%). Factor analysis revealed 2 main components of cystitic symptoms: "feeling out of sorts" (generalized symptoms) predominantly found among women aged 50-65 years, and the "distressed bladder" (voiding-related and local, constant symptoms) most often in the group aged 18-35 years. No differences in frequency or degree of symptoms were related to the presence of bacteriuria. In conclusion, generalized symptoms of feeling out of sorts are frequent in adult women with acute uncomplicated lower UTI, and equally frequent in all ages whether the patient shows bacteriuria or not.     

Asymptomatic bacteriuria in the Port Harcourt metropolis of Nigeria

The Port Harcourt metropolis of Nigeria was screened to establish the prevalence of asymptomatic bacteriuria (ABU) over a 3 year period. An occurrence rate of 15% was detected. The females presented a higher incidence rate (9%) than the males (6%). Previous history of urinary tract infection (UTI) was seen to be contributory to ABU; so also was sexual activity. Of the isolates obtained, Escherichia coli was found to be predominant (45%). An isolation rate of 3.7% was realised for Staphylococcus epidermidis. This emphasizes its role in UTI. The advantages of screening for ABU was examined and it is suggested that individuals should be screened for ABU at least twice a year.     

Uropathogenic Escherichia coli Superinfection Enhances the Severity of Mouse Bladder Infection

Urinary tract infections (UTIs) afflict over 9 million women in America every year, often necessitating long-term prophylactic antibiotics. One risk factor for UTI is frequent sexual intercourse, which dramatically increases the risk of UTI. The mechanism behind this increased risk is unknown; however, bacteriuria increases immediately after sexual intercourse episodes, suggesting that physical manipulation introduces periurethral flora into the urinary tract. In this paper, we investigated whether superinfection (repeat introduction of bacteria) resulted in increased risk of severe UTI, manifesting as persistent bacteriuria, high titer bladder bacterial burdens and chronic inflammation, an outcome referred to as chronic cystitis. Chronic cystitis represents unchecked luminal bacterial replication and is defined histologically by urothelial hyperplasia and submucosal lymphoid aggregates, a histological pattern similar to that seen in humans suffering chronic UTI. C57BL/6J mice are resistant to chronic cystitis after a single infection; however, they developed persistent bacteriuria and chronic cystitis when superinfected 24 hours apart. Elevated levels of interleukin-6 (IL-6), keratinocyte cytokine (KC/CXCL1), and granulocyte colony-stimulating factor (G-CSF) in the serum of C57BL/6J mice prior to the second infection predicted the development of chronic cystitis. These same cytokines have been found to precede chronic cystitis in singly infected C3H/HeN mice. Furthermore, inoculating C3H/HeN mice twice within a six-hour period doubled the proportion of mice that developed chronic cystitis. Intracellular bacterial replication, regulated hemolysin (HlyA) expression, and caspase 1/11 activation were essential for this increase. Microarrays conducted at four weeks post inoculation in both mouse strains revealed upregulation of IL-1 and antimicrobial peptides during chronic cystitis. These data suggest a mechanism by which caspase-1/11 activation and IL-1 secretion could predispose certain women to recurrent UTI after frequent intercourse, a predisposition predictable by several serum biomarkers in two murine models.     

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.     

Pathogenesis of urinary tract infection in the elderly: the role of bacterial adherence to uroepithelial cells

The in vitro adherence of nine strains of Gram-negative bacteria to uroepithelial cells from 24 women patients (>65 years) was significantly higher than to cells from 24 premenopausal women (18–40 years). Uroepithelial cells from patients with a history of previous urinary tract infection (UTI) were marginally more receptive to attachment of uropathogens than cells from women without a history of UTI, but this was not statistically significant. Serum from four elderly women with asymptomatic bacteriuria was used to stabilize samples for electron-microscopic examination, which showed the presence of fibrous glycocalyx material surrounding the bacteria and attached to the uroepithelial cells. Eighty uropathogenic isolates from elderly and premenopausal women were found to express adhesins, to produce urease and hemolysins, and to ferment sucrose, salicin, and dulcitol. These results suggest that the increased receptivity of uroepithelial cells to bacterial attachment may be a predisposing factor in the onset of UTI in the hospitalized and domiciliary elderly population.     

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.     

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.     

Changes in urine levels of substance P,vasoactive intestinal peptide and calcitonin-gene-related peptide in patients with urinary tract infections

Urinary tract infections (UTI) are important health problems and predisposing causes of UTI are not entirely known. Neuro-immune interactions play an important role in human health and disease. Capsaicin-sensitive sensory nerves which in nerve bladder extensively regulate immune system through neuropeptides such as substance P (SP), calcitonin-gene related peptide (CGRP) and vasoactive intestinal peptide (VIP). In addition these neuropeptides also have anti-bacterial effects. To determine how the levels of these peptides changes during UTI, 67 patients (50–90 years-old) diagnosed with UTI in Akdeniz University Faculty of Medicine Hospital were compared with 37 healthy people 50 years or older as the control group. Additionally, 7 patients with UTI symptoms (dysuria, urgency) but with sterile pyuria were also included in the study. Urine samples from 15 patients, whose symptoms regressed with control urine cultures being sterile, were taken after completion of the treatments. Urine neuropeptide levels were determined by ELISA. CGRP levels are significantly higher in patients with UTI, but did not associate with pyuria whereas SP and VIP levels were significantly lower in patients with sterile pyuria, indicating sensory nerve deficiency. Since CGRP exerts immunosuppressive effects, increased levels of the peptide may predispose to UTI. Furthermore, the connection between the observed sensory nerve deficiency and sterile pyuria warrants further studies.     

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.     

Influence of P blood group phenotype on susceptibility to urinary tract infection

Bacterial attachment is an important event in the pathogenesis of urinary tract infection (UTI). Increased receptivity on the host cells has been suggested influence proneness to infection. The dual function of the globoseries of glycolipids both as receptors for attaching E. coli and as P blood group antigens lead us to examine the P blood group phenotype distribution in UTI prone patient populations. A correlation between the P1 blood group phenotype and susceptibility to UTI was found. Patients with recurrent pyelonephritis had 74/79 (94%), P1 compared to 75% in healthy controls. In contrast patients with asymptomatic bacteriuria (ABU) had a reduced frequency of P1, 43/74 (58%). P1 and P2 individuals differ in amount and composition of the globoseries of glycolipids on their erythrocytes. A similar difference in other tissues, e.g. uroepithelial cells might explain the association of P1 with UTI. There was, however, no significant difference in bacterial adherence to uroepithelial cells from P1 and P2 individuals. Other mechanisms explaining the increase in P1 individuals in recurrent pyelonephritis are discussed.     

Do type 1 fimbriae promote inflammation in the human urinary tract?

Type 1 fimbriae have been implicated as virulence factors in animal models of urinary tract infection (UTI), but the function in human disease remains unclear. This study used a human challenge model to examine if type 1 fimbriae trigger inflammation in the urinary tract. The asymptomatic bacteriuria strain Escherichia coli 83972, which fails to express type 1 fimbriae, due to a 4.25 kb fimB-fimD deletion, was reconstituted with a functional fim gene cluster and fimbrial expression was monitored through a gfp reporter. Each patient was inoculated with the fim+ or fim- variants on separate occasions, and the host response to type 1 fimbriae was quantified by intraindividual comparisons of the responses to the fim+ or fim- isogens, using cytokines and neutrophils as end-points. Type 1 fimbriae did not promote inflammation and adherence was poor, as examined on exfoliated cells in urine. This was unexpected, as type 1 fimbriae enhanced the inflammatory response to the same strain in the murine urinary tract and as P fimbrial expression by E. coli 83972 enhances adherence and inflammation in challenged patients. We conclude that type 1 fimbriae do not contribute to the mucosal inflammatory response in the human urinary tract.     

Prevalence of Symptomless Urinary Tract Disease in Birmingham Schoolchildren. I—Pyuria and Bacteriuria

In a pilot project 2,122 schoolchildren were screened for symptomless urinary tract disease by the examination of midstream urine specimens. These were tested for albumin, blood, and glucose with Labstix commercial strips, together with microscopy for abnormal cellular excretion.One case of renal glycosuria was found but none of previously undiagnosed diabetes mellitus. Out of 1,096 boys, 11 (1%) had pyuria—a leucocyte count greater than 10/cu.mm.—but only four showed abnormal counts on retesting. None had urinary tract infection.Out of 1,026 girls, 96 (9·3%) had pyuria initially but 35 were normal on retesting. Of the remaining 61 girls, 59 attended the outpatients department for further investigation, and in 30 vulvitis appeared to be the sole cause. Ten were proved to have significant bacteriuria and six of them showed radiological abnormalities.It is suggested that careful long-term studies are needed to study the economics and the implications of screening on a national scale.     

Enterococcus faecalis: specific and non-specific interactions with human polymorphonuclear leukocytes

In previous studies we have demonstrated that the ability of Enterococcus faecalis to adhere to and to be internalized in human urinary tract epithelial cells, Girardi Heart cells and human polymorphonuclear leukocytes (PMNs), was dependent on whether the strain had been isolated from urinary tract infections (UTI) or endocarditis (EN) respectively. These properties were further modified by growth of the organism in human serum. In the present report, using competition assays we show that adhesins containing a D-glucose moiety play a role in mediating the interactions between human PMNs and E. faecalis strains isolated from UTI and grown in brain-heart infusion broth (BHIB). On the other hand, adhesins containing both D-glucose and D-galactose moieties were involved in the interactions between PMNs and serum grown UTI isolates or EN isolates grown in either BHIB or human serum. Moreover, the impairment in the association between both UTI and EN strains after growth in serum appears to be at least partially related to a decrease in enterococcal surface hydrophobicity.     

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.     

Intestinal population dynamics of UTI-causing Escherichia coli within heterosexual couples

From October 1999 to July 2001, a prospective cohort study was conducted to assess the intestinal Escherichia coli population dynamics of 23 sexually active couples. We tested the hypothesis that intestinal persistence and predominance of specific E. coli strains, co-colonization of sex partners with the same E. coli strain, and the intestinal diversity of fecal E. coli, contribute to recurrent urinary tract infection (UTI). E. coli isolates causing UTI, asymptomatic bacteriuria (ABU), or intestinal co-colonization were evaluated by ERIC2 PCR and compared with strains recovered exclusively from stool samples with respect to intestinal persistence, predominance, and diversity. Contrary to our hypothesis, UTI-causing strains exhibited similar levels of intestinal persistence and predominance as did fecal strains, and UTI episodes were not associated with shifts in fecal E. coli diversity. In contrast, intestinal co-colonization strains exhibited greater persistence and predominance than did fecal strains and were more likely to cause ABU, and co-colonization episodes were associated with significantly increased fecal E. coli diversity. Nonetheless, intestinal co-colonization strains were not associated with UTI. These findings suggest that E. coli strains involved in co-colonization may be more important contributors to intestinal E. coli dynamics than to UTI pathogenesis.